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Acute Lead Toxicosis in Mourning Doves
Abstract
Previous research has suggested that free-ranging mourning doves (Zenaida macroura) may ingest spent lead pellets, succumb to lead toxicosis, and die in a relatively short time (i.e., an acute lead toxicosis hypothesis). We tested this hypothesis by administering 157 captive mourning doves 2–24 lead pellets, monitoring pellet retention and short-term survival, and measuring related physiological characteristics.
During the 19- to 21-day posttreatment period, 104 doves that received lead pellets died (deceased doves) and 53 survived (survivors); all 22
birds in a control group survived. Within 24-hr of treatment, blood lead levels increased almost twice as fast for deceased doves compared to survivors (F1,208 = 55.49; P < 0.001). During the first week, heterophil:lymphocyte (H:L) ratios increased twice as fast for deceased doves than with survivors (F1,198 = 23.14, P , 0.001). Posttreatment survival differed (X2 = 37.4, P < 0.001) among the 5 groups of doves that retained different numbers of pellets, and survival ranged from 0.57 (95% CI: 0.44–0.74) for doves that retained �2 lead pellets 2 days posttreatment compared to 0.08 (95% CI: 0.022–0.31) for those doves that retained 13–19 lead pellets on 2 days posttreatment; significant differences existed among the 5 groups. After controlling for dove pretreatment body mass, each additional lead pellet increased the hazard of death by 18.0% (95% CI: 1.132–1.230, P < 0.001) and 25.7% (95% CI: 1.175–1.345, P < 0.001) for males and females, respectively. For each 1-g increase in pretreatment body mass, the hazard of death decreased 2.5% (P ¼ 0.04) for males and 3.8% (P ¼ 0.02) for females. Deceased doves had the
highest lead levels in liver (49.20 6 3.23 ppm) and kidney (258.16 6 21.85 ppm) tissues, whereas controls showed the lowest levels (liver, 0.08 ppm; kidney, 0.17 ppm). For doves dosed with pellets, we observed simultaneous increases in blood lead levels and H:L ratios, whereas packed-cell volume (PCV) values declined. Our results support an acute lead toxicosis hypothesis. Although further research is necessary to investigate the magnitude of lead shot ingestion and toxicosis in mourning doves, we recommend that management agencies initiate development of a long-term strategic plan aimed at implementing a nontoxic shot regulation for mourning dove hunting. (JOURNAL OF WILDLIFE MANAGEMENT 70(2):413–421; 2006)
... Research findings accumulated over several decades have documented effects of spent lead hunting ammunition on numerous wildlife species Norris 1995, Tranel andKimmel 2009), identifying exposure primarily through ingestion of lead shotgun pellets, bullet fragments in gut piles, unretrieved animal carcasses, or ingestion of lost fishing tackle (Schulz et al. 2006a(Schulz et al. , 2007aFinkelstein et al. 2012;Haig et al. 2014;Grade et al. 2018). Progress has been made in reducing lead poisoning in North American waterfowl (Anderson et al. 2000, Schulz et al. 2006b), but the problem persists for other wildlife species, including California condors (Gymnogyps californianus), bald eagles (Haliaeetus leucocephalus), mourning doves (Zenaida macroura), common loons (Gavia immer), and swans (Cygnus spp). ...
... These 6 subissues share similar characteristics while demonstrating differences in exposure pathways, tolerances, effects, and stakeholder interests. For example, mourning doves and other surface-feeding songbirds directly ingest lead shotgun pellets on managed crop fields designed to attract feeding birds (Schulz et al. 2002(Schulz et al. , 2006a(Schulz et al. , 2007aPlautz et al. 2011), whereas scavenging birds like eagles and condors indirectly ingest lead bullet fragments in gut piles and carcasses from high-powered rifles (Hunt et al. 2006, Finkelstein et al. 2012, Herring et al. 2016, or loons ingest discarded lead fishing tackle Chafel 1992, Grade et al. 2018). Susceptibility varies among avian species with condors, vultures (Cathartes aura), and ravens (Corvus corax) seemingly able to tolerate greater blood lead levels (Craighead and Bedrosian 2008, Kelly et al. 2014) compared with bald eagles (Bedrosian et al. 2012) and mourning doves (Schulz et al. 2006a(Schulz et al. , 2007a. ...
... For example, mourning doves and other surface-feeding songbirds directly ingest lead shotgun pellets on managed crop fields designed to attract feeding birds (Schulz et al. 2002(Schulz et al. , 2006a(Schulz et al. , 2007aPlautz et al. 2011), whereas scavenging birds like eagles and condors indirectly ingest lead bullet fragments in gut piles and carcasses from high-powered rifles (Hunt et al. 2006, Finkelstein et al. 2012, Herring et al. 2016, or loons ingest discarded lead fishing tackle Chafel 1992, Grade et al. 2018). Susceptibility varies among avian species with condors, vultures (Cathartes aura), and ravens (Corvus corax) seemingly able to tolerate greater blood lead levels (Craighead and Bedrosian 2008, Kelly et al. 2014) compared with bald eagles (Bedrosian et al. 2012) and mourning doves (Schulz et al. 2006a(Schulz et al. , 2007a. ...
Although lead poisoning in North American waterfowl has been reduced, it persists among other wildlife. To address this issue, we review lead poisoning in wildlife and threats to human health, describe the recent socio‐political landscape, and develop a framework for reducing lead exposure related to hunting ammunition and fishing tackle. Despite substantial information about lead poisoning in wildlife, an explicit and strategic plan for using existing information to develop an effective communication program is lacking. Local and regional efforts encouraging hunters and anglers to voluntarily use nonlead alternatives could benefit from a nationally coordinated and strategic focus. We propose that the diffusion of innovation theory provides a useful framework for developing and implementing voluntary nonlead hunting ammunition and fishing tackle programs. Further, it can help communicators refine messages, increase efficiencies in developing communication materials, and monitor adoption of nonlead alternatives. The initial step in this process, however, is to engage stakeholders about the importance of the issue and leverage that concern as a catalyst for positive change. Published 2019. This article is a U.S. Government work and is in the public domain in the USA. We review lead poisoning in wildlife and threats to human health, describe the recent socio‐political landscape, and develop a framework for reducing lead exposure related to hunting ammunition and fishing tackle. Encouraging voluntarily use of nonlead alternatives could benefit from a nationally coordinated and strategic focus based on the diffusion of innovation theory.
... In lead-exposed birds, lead concentrations are often greater in kidney than liver of many species (Longcore et aJ. 1974b, Custer et al. 1984, Beyer et al. 1988, Marn et al. 1988, Carpenter et al. 2003, Beyer et al. 2004, Pattee et al. 2006, Schulz et al. 2006. However, the reverse has been reported for eagles and some other raptors , Wayland et al. 1999, Iwata et al. 2000, Kenntner et al. 2001, Krone et al. 2004, Battaglia et al. 2005, Martin et al. 2008. ...
... The biological significance of a tissue lead concentration may, therefore, be difficult to determine if the history of the bird is unknown. The chronicity of exposure is (1979), poisoning Degernes (1991) Clinical poisoning 50-100 6--10 6-15 Longcore et al. (1974b), Degernes (1991), Beyer et al. (2000) Severe clinical >100 >10 >15 Cook and Trainer (1966), Longcore poisoning et al. (I 974b), Mautino and Bell (1986), Beyer et al. (1988Beyer et al. ( , 2000, Pain and Rattner (1988), Pain (1989), Blus et al. (1991Blus et al. ( , 1999, Degernes (1991), Kelly et al. (1998), Nakade et al. (2005), Degernes et al. (2006) Falconiformes Subclinical 20<50 2<6 2 < 4 d Custer et al. (1984), Henny et al. poisoning (1991), Kramer and Redig (1997) Clinical poisoning 50-100 6-10 4-6" Lumeij et al. (1985), Kramer and Redig (1997) Severe clinical >100 >10 >6 d Redig et al. (1980), Hoffman et al. poisoning (1981), Pattee et al. (1981Pattee et al. ( , 2006, Langelier et al. (1991), Kramer and Redig (1997) Columbiformes Subclinical 20 < 200 2<6 2 < 15 Ohi et al. (1974), Cory-Slechta et al. poisoning (1980), , , DeMent et al. (1987), Scheuhammer and Wilson (1990) Clinical poisoning 200-300 6--15 15-30 Cory-Slechta et al. (1980), Anders et al. (1982), Boyer et al. (1985) Severe clinical >300 >15 >30 Locke and Bagley (1967), Barthalmus poisoning et al. (1977), Cory-Slechta et al. (1980), Anders et al. (1982), Boyer et al. (1985), Schulz et al. (2006) " Lead concentrations in bone reflect lifetime accumulation and chronic low exposure to lead may result in similar concentrations in bone as acute exposure to higher levels. If evidence of acute exposure exists, we recommend that bone lead concentrations (dry weight basis) of < I 0 flg/g be considered background, 10-20 flg/g be considered evidence of subclinical to clinical poisoning, and >20 flg/g be considered evidence of severe clinical poisoning. ...
... Lead concentrations in tissues associated with poisoning in birds vary among orders, with Galliformes and Columbiformes often having higher residues than others , Kendall et al. 1983, Gjerstad and Hanssen 1984, Reichel et al. 1984, Beyer et al. 1988, 1998, Vyas et al. 2001, Lewis et al. 2001, Schulz et al. 2006). Within-order differences among species also have been noted, as lead-poisoned Anseriformes of lighter weight tended to have higher lead concentrations in the liver than species of greater weight (Beyer et al. 1998). ...
Lead is a highly toxic heavy metal that acts as a nonspecific poison affecting all body systems and has no known biological requirement. Absorption of low concentrations may result in a wide range of sublethal effects in animals, and higher concentrations may result in mortality (Demayo et al. 1982). Lead has been mined and smelted by humans for centuries, but the use of lead-based products increased greatly following the Industrial Revolution. Consequently, lead today is ubiquitous in air, water, and soil, in both urban and rural environments (Eisler 2000). Vertebrates are exposed to lead mainly via inhalation and ingestion. A proportion of lead entering the body is absorbed into the bloodstream and subsequently becomes distributed among body tissues, primarily the blood, liver, kidney, and bone. As a result of anthropogenic activities, most animals have higher tissue lead concentrations than in preindustrialized times. Although even very low tissue lead concentrations have some measurable physiological effects, the concentrations usually encountered in the wider environment (i.e., distant from lead emission sources) have not generally been considered to directly affect survival of most wildlife.
... However, in general, the highest lead concentrations are found in bone, followed by kidney and liver, with intermediate concentrations in brain and blood, and the lowest concentrations in muscle (Longcore et al. 1974b, Johnson et al. 1982, Custer et al. 1984, Garcia-Fernandez et al. 1995. In lead-exposed birds, lead concentrations are often greater in kidney than liver of many species (Longcore et al. 1974b, Custer et al. 1984, Beyer et al. 1988, Marn et al. 1988, Carpenter et al. 2003, Beyer et al. 2004, Pattee et al. 2006, Schulz et al. 2006). However, the reverse has been reported for eagles and some other raptors , Wayland et al. 1999, Iwata et al. 2000, Kenntner et al. 2001, Krone et al. 2004, Battaglia et al. 2005, Martin et al. 2008. ...
... The biological significance of a tissue lead concentration may, there fore, be difficult to determine if the history of the bird is unknown. The chronicity of exposure is Mautino and Bell (1986), Beyer et al. (1988Beyer et al. ( , 2000, Pain and Rattner (1988), Pain (1989), Blus et al. (1991Blus et al. ( , 1999, Degernes (1991), Kelly et al. (1998) Anders et al. (1982), Boyer et al. (1985), Schulz et al. (2006) a Lead concentrations in bone reflect lifetime accumulation and chronic low exposure to lead may result in similar concen trations in bone as acute exposure to higher levels. If evidence of acute exposure exists, we recommend that bone lead concentrations (dry weight basis) of <10 µg/g be considered background, 10-20 µg/g be considered evidence of subclinical to clinical poisoning, and >20 µg/g be considered evidence of severe clinical poisoning. ...
... Lead concentrations in tissues associated with poisoning in birds vary among orders, with Galliformes and Columbiformes often having higher residues than others , Kendall et al. 1983, Gjerstad and Hanssen 1984, Reichel et al. 1984, Beyer et al. 1988, 1998, Vyas et al. 2001, Lewis et al. 2001, Schulz et al. 2006). Within-order differences among species also have been noted, as lead-poisoned Anseriformes of lighter weight tended to have higher lead concentrations in the liver than species of greater weight (Beyer et al. 1998). ...
... Lead poisoning in birds is typically a chronic disease which often results in the development of clinical signs that include weakness, emaciation, and anemia. Although the relationship between ingested lead shot and toxicological effects depends on many factors, including species, diet, body condition, and environmental factors, one #7.5 or #8 ingested lead pellet may cause acute mortality in Mourning Doves (Buerger et al. 1986, Schulz et al. 2006a. Even in the absence of direct mortality from lead toxicosis, one ingested lead pellet may result in sublethal effects on physiology and behavior that can lead to death from starvation, predation, or disease (Scheuhammer andNorris 1996, Schulz et al. 2006a). ...
... Liver lead concentrations of 2 parts per million (ppm) wet weight (about 6 ppm dry weight) or greater are generally considered elevated in birds, including Mourning Doves, while concentrations of 6 ppm wet weight (about 20 ppm dry weight) or greater are potentially toxic (Franson 1996, Pain 1996. In a recent experimental lead shot dosing study in Mourning Doves, surviving birds had a mean liver lead concentration of 3.4 ppm, wet weight, while the mean of those that died was 49.2 ppm (Schulz et al. 2006a). Bone lead concentrations are often used as a measure of chronic exposure, because lead is lost from bone very slowly (Sanderson andBellrose 1986, Pain 1996). ...
... The liver and bone lead concentrations (Table 5) that we found in Mourning Doves with ingested lead shot were generally lower than the lead concentrations reported in experimental dosing studies and in field cases of lead poisoning in Mourning Doves, where liver and bone lead concentrations have ranged from about 80 to >200 ppm dry weight and 115 to >400 ppm dry weight, respectively (Locke and Bagley 1967, Kendall et al. 1983, Buerger et al. 1986, Schulz et al. 2006a). It is not surprising that the hunter-harvested doves with ingested lead pellets in our sample had lower concentrations of lead in their tissues than birds that died of lead poisoning, because the severity of poisoning would not have progressed to a near-terminal stage in birds still able to take flight. ...
A more complete understanding of nonhunting and harvest mortality for Mourning Doves (Zenaida macroura) will be critical to improving regional and national harvest management decisions. Poisoning from ingested lead shot is of particular concern in Mourning Doves, which are often hunted on managed shooting fields where lead shot densities can be high, potentially increasing the risk of lead exposure. Previous studies of lead exposure in Mourning Doves have been local in scope and sample sizes have varied widely among areas. We provide an evaluation of lead exposure in 4,884 hunter-harvested Mourning Doves from Arizona, Georgia, Missouri, Oklahoma, Pennsylvania, South Carolina, and Tennessee. Overall, the frequency of ingested lead pellets in gizzards of doves on hunting areas where the use of lead shot was permitted was 2.5%, although we found a high degree of variability among locations. On areas where non-toxic shot was required, 2.4% of Mourning Doves had ingested steel shot. Hatch year (HY) doves had a greater frequency of ingested lead and steel pellets than after hatch year (AHY) birds, suggesting that they either ingested pellets more frequently or that young birds with ingested shot were preferentially harvested over older birds with ingested pellets. In doves without ingested lead pellets, bone lead concentrations were lower on an area requiring the use of nontoxic shot than on areas allowing the use of lead shot.
... Although lead shot was completely banned for waterfowl hunting in the United States by 1992 (U.S. Fish and Wildlife Service [USFWS] 1988, Belanger and Kinnane 2002), it continues to be used extensively for upland game bird hunting. Despite its continued use, there is growing concern about the risks related to exposure of upland game birds to spent lead shot resulting from hunting activities (Franson 1996, Keel et al. 2002, and much of the concern is focused on mourning doves (Kendall et al. 1996, Schulz et al. 2002, 2006a. Given this heightened awareness of lead exposure and toxicosis in mourning doves, further nontoxicshot regulations will be a contentious policy debate (Franson 1996, Kendall et al. 1996, Belanger and Kinnane 2002. ...
... with considerable year-to-year variation among areas (Franson 2002). Along with the information on exposure and ingestion of lead shot, there is substantial information documenting the ultimate linkage to lead toxicosis in mourning doves (Kendall et al. 1996, Schulz et al. 2006a). ...
... During 1998-2000, pellet ingestion rates were 2.5% of 4,229 carcasses collected from 7 states where the use of lead shot was permitted (Franson 2002). In combination with these existing ingestion rates, evidence from wild mourning doves held in captivity (Schulz et al. 2006a) showed that virtually all mourning doves ingesting lead pellets eventually succumb to the direct or indirect effects of lead toxicosis. Given the range of 350-600 million mourning doves in North America (Dunks et al. 1982) and multiplying the lower and upper estimates by Franson's (2002) reported 2.5% ingestion rate, it may be possible that roughly 8.8-15.0 million mourning doves are dying from lead poisoning annually. ...
Increasing concerns about the exposure of mourning doves (Zenaida macroura) to spent lead shot may lead to a review of lead-shot restrictions. Policy reviews regarding current restrictions likely will involve debates about whether nontoxic-shot requirements will result in increased crippling loss of mourning doves. We evaluated waterfowl crippling rates in the United States prior to, during, and after implementation of nontoxic-shot regulations for waterfowl hunting. We use this information to make inferences about mourning dove crippling rates if nontoxic-shot regulations are enacted. We found differences in moving average crippling rates among the 3 treatment periods for ducks (F = 23.232, P < 0.001, n = 49). Prenontoxic-shot-period crippling rates were lower than 5-year phase-in period crippling rates (P = 0.043) but higher (P < 0.001) than nontoxic-shot-period crippling rates. Similarly, we observed differences in moving average crippling rates among the 3 treatment periods for geese (F = 9.385, P < 0.001, n = 49). Prenontoxic-shot- and 5-year-phase-in-period crippling rates were both greater than (P < 0.001) nontoxic-shot-period crippling rates but did not differ from one another (P = 0.299). Regardless of why the observed increases occurred in reported waterfowl crippling rates during the phase-in period, we believe the decline that followed full implementation of the nontoxic-shot regulation is of ultimate importance when considering the impacts of lead shot restrictions for mourning doves. We argue that long-term mourning dove crippling rates might not increase as evidenced from historical waterfowl data.
... However, the results of other studies add a layer of ambiguity to this topic that is important to acknowledge. For example, even at relatively similar Pb exposure levels, studies have shown clear effects on blood chemistry (Kerr et al. 2010, Carpenter et al. 2003, Hoffman et al. 1981, Pattee et al. 2006, egg production (Edens and Garlich 1983), behavior Gochfeld 1994, 2004), and survival (Schulz et al. 2006, Grand et al. 1998, Pattee et al. 2006, Rideout et al. 2012, whereas others demonstrated limited responses to many of the same endpoints (McBride et al. 2004, Schulz et al. 2007, Ferrandis et al. 2008). Although differences in methodology likely played some role, a more plausible explanation is intrinsic interindividual and interspecific variability in sensitivity to Pb. ...
... 7.5). Muscle erosion occurred in ,22 days in captive birds(Schulz et al. 2006). Photo courtesy of John Schulz.The Condor: Ornithological Applications 116:408-428, Q 2014 Cooper Ornithological Society ...
Lead (Pb) is a metabolic poison that can negatively influence biological processes, leading to illness and mortality across a large spectrum of North American avifauna (>120 species) and other organisms. Pb poisoning can result from numerous sources, including ingestion of bullet fragments and shot pellets left in animal carcasses, spent ammunition left in the field, lost fishing tackle, Pb-based paints, large-scale mining, and Pb smelting activities. Although Pb shot has been banned for waterfowl hunting in the United States (since 1991) and Canada (since 1999), Pb exposure remains a problem for many avian species. Despite a large body of scientific literature on exposure to Pb and its toxicological effects on birds, controversy still exists regarding its impacts at a population level. We explore these issues and highlight areas in need of investigation: (1) variation in sensitivity to Pb exposure among bird species; (2) spatial extent and sources of Pb contamination in habitats in relation to bird exposure in those same locations; and (3) interactions between avian Pb exposure and other landscape-level stressors that synergistically affect bird demography. We explore multiple paths taken to reduce Pb exposure in birds that (1) recognize common ground among a range of affected interests; (2) have been applied at local to national scales; and (3) engage governmental agencies, interest groups, and professional societies to communicate the impacts of Pb ammunition and fishing tackle, and to describe approaches for reducing their availability to birds. As they have in previous times, users of fish and wildlife will play a key role in resolving the Pb poisoning issue.
... In one experiment, mourning doves that ingested even just one or two pellets showed an almost immediate spike in BLLs and also had higher lead levels in their liver and kidneys post-mortem (Schulz et al. 2007). In another experiment, mourning doves administered even a single lead pellet had rapid increases in BLLs within 24-hours, and death occurred in 104 out of 157 birds (Schulz et al. 2006). Ingestion of a single pellet by a mourning dove increased the rate of mortality by 24% (Buerger et al. 1986). ...
... Ingestion of a single pellet by a mourning dove increased the rate of mortality by 24% (Buerger et al. 1986). In addition the chance of death increases by 18% for each pellet administered (Schulz et al. 2006). ...
Ingestion of lead rifle bullet fragments found in discarded hunter-harvested ungulate gut piles negatively affects avian wildlife. Some large carnivores, such as grizzly bears, are also known to target these gut piles as a food source and are therefore potentially at risk of lead exposure. We investigated whether large carnivores in the greater Yellowstone ecosystem were exposed to lead, and if so, if ammunition ingested from gut piles was an apparent source of exposure. Grizzly bears (JJrsus arctos, n — 82) exhibited higher blood lead levels (median = 4.4 μg/dL, range 1.1-18.6 μg/dL) than black bears (JJrsus americanas, n = 35, median = 1.6, range 0.5-6.9 μg/dL), but blood lead levels did not increase during the autumn hunting season when potentially lead-tainted gut piles are available. Wolves (Cants lupus, n = 21) and cougars (Puma concolor, n = 8) showed lead concentrations near or below the minimum level of detection in both blood and tissue samples. Unlike findings in previous studies on avian scavengers, we did not find lead ammunition fragments to be a widespread source of lead exposure in large carnivores. Grizzly bears do, however, exhibit blood lead levels that are higher than what is considered safe in humans, but the source of this exposure remains unknown.
... Our next objective was to test the acute lead toxicosis hypothesis, that free-ranging Mourning Doves may ingest spent lead pellets, succumb to lead toxicosis, and die in a relatively short time (Schulz et al. 2006) . We tested this hypothesis by administering 157 captive Mourning Doves 2-24 lead pellets, monitoring pellet retention and short-term survival, and measuring related physiological characteristics. ...
... Liver (P <0.0001) and kidney (P = 0.0012) lead levels for doves ingesting pellets were higher than doves without ingested pellets. Our lead pellet ingestion rates were similar to previously reported ingestion rates from hunter-killed doves (Kendall et al. 1996, Otis et al. 2008, and our physiological measurements confirm earlier reports of a rapid and acute lead toxicosis (Schulz et al. 2006). Similar to previous field research (Lewis and Legler 1968, Castrale 1991, Best et al. 1992), we did not observe a relationship between pellet density in the food and ad libitum pellet ingestion. ...
... Lead is toxic to humans and wildlife because it affects the function and structure of a vertebrate's kidney, bone, central nervous system, and hematopoietic systems and produces adverse biochemical, histopathological, neurophysical, fetotoxic, teratological, and reproductive effects (Eisler 1988, Schulz et al. 2006. For these reasons, the USEPA's action level for lead in water delivered to users of public drinking water systems is 15 µg/L, but the goal for lead is zero. ...
... Thus, studies that are more recent have examined terrestrial avian species. For example, of 157 doves fed 2 to 24 lead shot pellets, 104 died prior to the conclusion of the study while all 22 control doves survived (Schulz et al. 2006). Similarly, lead poisoning has been blamed for the loss of California condors. ...
Environmental issues for small arms training with lead projectiles are examined in this report for Camp Edwards, Massachusetts, in order to evaluate whether past or future use of lead in small arms has or will result in lead mobilization to groundwater. A review of relevant literature and case studies demonstrates lead is toxic to humans and wildlife and, therefore, exposure must be minimized. The literature also demonstrates lead mobilization occurs chiefly by wind and surface water erosion, generally not by dissolution and leaching through soil. Environmental conditions at Camp Edwards dictate that wind and surface water are not primary avenues of transport, due to extensive vegetative cover and highly permeable soils. Highly permeable soils limit corrosion of metallic lead but can facilitate transport for dissolved forms of lead. Because highly permeable soils favor transport, careful analysis of the geochemical conditions with respect to lead vertical transport to groundwater was a focus for this study. It is the conclusion of this study that lead has not contaminated the groundwater in any significant way based on the absence of lead plumes, and only one groundwater monitoring well associated with the small arms ranges had a single low lead detection < 2 ppb.
... 19 Lead is toxic to humans and wildlife because it affects the function and structure of a vertebrate's kidney, bone, central nervous system, and hematopoietic systems, and produces adverse biochemical, histopathological, neurophysical, fetotoxic, teratological, and reproductive effects. 46,184 Lead toxicity occurs, in part, because of competitive binding. The stability constants for lead complexes are so much stronger than those of essential elements that differences in concentration are overcome and even small excesses may deprive essential elements of their biological carriers or retaining ligands. ...
... For example, of 157 doves fed 2-24 lead shot pellets, 104 died prior to the conclusion of the study, whereas all 22 control doves survived. 184 Similarly, lead poisoning has been blamed for the death of some California condors. A study of condor mortality was unable to identify with certainty the source of lead, but included military rifle ranges at Camp Roberts and Fort Hunter Liggett as possibilities. ...
Lead has been widely introduced into the environment for centuries and lead toxicity has been well known for decades. Despite hundreds of articles describing lead's interaction with the environment, questions continue to be raised regarding the extent to which the element may migrate through soil and the vadose zone and contaminate groundwater. The authors examined lead geochemistry and field data and conclude that lead may migrate short distances in surface and pore water but that reports of lead in groundwater are related to vanishingly low natural concentrations, direct introduction of lead, or errors during sample handling or analysis.
... Lead pellet ingestion rates for hunter-killed mourning doves vary from ,1.0% to 6.5%, depending upon locale (Conti 1993, Mirarchi andBaskett 1994). Although a relatively small proportion of hunter-killed doves apparently ingest pellets, suggesting that the problem is not a serious management concern, some existing data suggest that doves ingesting pellets may ingest multiple pellets and die relatively quickly (Schulz et al. 2006). For example, Lewis and Legler (1968) reported 7 of 14 doves that ingested shot had ingested 3 lead pellets and 1 of 14 had ingested 24 lead pellets. ...
... Declines in several resident upland game bird populations (e.g., northern bobwhite [Colinus virginianus] and ringnecked pheasants [Phasianus colchicus]) have prompted wildlife managers to increase mourning dove shooting opportunities on public lands, especially near urban population centers, and to create attractive feeding spots for doves and popular opportunities for hunters (Schulz et al. 2003a). Given these increased hunting activities and the available information about the toxic effects of spent lead shot (Kendall et al. 1996;Schulz et al. 2002Schulz et al. , 2006, further nontoxic-shot regulations likely are warranted. However, hunter attitudes and their acceptance of further nontoxicshot regulations play an important role in the policy-making process. ...
ABSTRACT Wildlife managers are becoming more concerned about the exposure of birds, in addition to waterfowl, to spent lead shot. Knowledge of hunter attitudes and their acceptance of nontoxic-shot regulations will be important in establishing new regulations. Our objective was to assess the attitudes of small game hunters in Missouri, USA, toward a nontoxic-shot regulation for small game hunting, specifically for mourning doves (Zenaida macroura). Most hunters (71.7–84.8%) opposed additional nontoxic-shot regulations. Hunters from rural areas, hunters with a rural background, hunters who hunt doves, hunters who currently hunt waterfowl, hunters who primarily use private lands, and current upland game hunters were more likely to oppose new regulations. For mourning dove hunting, most small game hunters (81.1%) opposed further restrictions; however, many non-dove hunters (57.1%) expressed no opinion. Because our results demonstrate that most small game hunters and dove hunters in Missouri are decidedly against further nontoxic-shot regulations, any informational and educational programs developed to accompany future policy changes must address their concerns.
... Animals ingesting deposited shot or feeding on wildlife contaminated via elevated soil or plant lead concentrations could be eaten by raptors. Surfacefeeding birds such as mourning doves (Zenaida macroura; Schulz et al., 2007) and American woodcock (Scolopax minor; French et al., 2017) may ingest available pellets, succumb to lead poisoning (Schulz et al., 2006), and be eaten by raptors or scavengers. In the same way, soils in heavily managed dove hunting fields may be lead contaminated (Castrale, 1989;Best, Garrison & Schmitt, 1992;Buck, 1998;Schulz et al., 2002) and earthworms and other taxa used for food by raptors can potentially transmit that lead to raptors (Slabe et al., 2019b). ...
... Previous research has proposed lead shot ingestion as a mortality factor among dove populations (Locke and Bagley 1967, Beurger et al. 1986, Kendall et al. 1996, Schulz et al. 2006a. Castrale (1989) found densities of lead shot significantly increased in fields used for dove hunting following the hunting season compared with preseason samples of the same fields. ...
Mourning doves are the most hunted game species in the United States. Mourning dove populations are declining, and the continued use of lead shot has been cited as one contributory factor. We examined the relationship between support for a ban on lead shot when dove hunting and 3 sets of variables: (1) beliefs about lead and steel shot, (2) prior dove hunting experiences, and (3) hunter demographics. Data were obtained from a mailed survey of 4,330 dove hunters in Illinois (response rate = 59%). Our results indicated that 81% of respondents were opposed to restrictions on the use of lead shot and these individuals believed that lead ammunition did not pose a risk to wildlife and that steel shot was less effective than lead shot. Supporters of banning lead shot were almost twice as likely to use steel shot, reported 2 fewer years hunting doves, went dove hunting 75% as much, and harvested 2/3 as many doves as those who opposed a ban. Consistent with social‐psychological theory, beliefs were the best predictors of whether an individual supported or opposed a ban, followed by dove hunting experiences and demographic variables.
... Lead pellet ingestion rates for hunter-killed mourning doves vary from <1.0 to 6.5% depending on locale (Conti, 1993;Mirarchi and Baskett, 1994;Kendall et al., 1996;Schulz et al., 2007). Considerable information exists demonstrating that dove hunters deposit large quantities of spent lead shot around favorable hunting locations, some proportion of doves ingest lead pellets while feeding on hunted fields, and most doves ingesting lead pellets eventually die from the immediate or secondary effects of lead poisoning (Schulz et al., 2006). Other wildlife species might similarly ingest lead and die. ...
... Lead exposure caused histopathological damages of liver and kidney, and bone mineralization reduction in birds (Álvarez-Lloret et al., 2014;Binkowski et al., 2013). Moreover, lead affected the hematopoietic system by reducing hematocrit, hemoglobin and erythrocyte ALAD (δ-aminolevulinic acid dehydratase) activity (Schulz et al., 2006). In addition, lead exposure can affect reproduction success by decreasing the fertility and egg production in laying hens and reducing sperm counts and quality in male birds (Vallverdú-Coll, 2016). ...
... Spent lead shot that has undergone decomposition in the topsoil to adsorbable lead compounds may be consumed by earthworms and so enter the food chain of birds and small mammals (Darling and Thomas, 2005). Mourning doves (Zenaida macroura) ingest spent lead shot on the ground and exhibit signs of acute lead toxicosis (Schultz et al., 2006). Lead shot is still permitted for hunting woodcock and snipe (Gallinago gallinago) across Canada, and Mourning doves and White-winged doves (Zenaida asiatica) in British Columbia, despite their falling under the federal regulations of the Canada Migratory Bird Convention Act which requires non-lead shot for migratory waterfowl hunting. ...
... Several authors have reviewed the exposure and effect of exposure of environmental lead poisoning in the mourning dove, and reported effects ranging from ill health to mortalities in the wild (Castrale, 1991;Schulz et al., 2006) and experimentally (Schulz et al., 2007). ...
... While waterfowl are exposed to Pb shot through direct consumption, secondary Pb poisoning of predatory scavenger species through the consumption of game animals harvested with Pb shot is a well-documented concern (Pain et al. 2009;Pokras and Kneeland 2009;Tranel and Kimmel 2009;Finkelstein et al. 2010Finkelstein et al. , 2012Haig et al. 2014). Future efforts should place additional focus upon other migratory gamebirds such as woodcock and Mourning Doves (Zenaida macroura; Schulz et al. 2006Schulz et al. , 2007 that are still legally harvested using Pb shot. Such research would improve the understanding of linkages among species' population trends, Pb health risks, potential impact of continued Pb shot use, as well as potential human health impacts from consumption of Pb-harvested birds. ...
Due to long term declines of American Woodcock (Scolopax minor) and widespread distribution of environmentally available lead (Pb) throughout their geographic range, it is important to assess if Pb exposure is a potential contributor to these declines. Woodcock are exposed to Pb through various environmental sources and are known to exhibit relatively high bone-Pb concentrations. Absorption of Pb by birds, and woodcock specifically, is not well understood. Some studies show that interactions among calcium, phosphorus, iron, zinc, and vitamin D levels may play an important role in Pb absorption. Therefore, when future Pb studies are performed for woodcock, and other birds, interactions among these elements should be considered. For example, these interactions are relevant in the acquisition and mobilization of calcium in female birds during egg development and shell calcification. These factors should be considered to understand potential mechanisms of Pb exposure, Pb absorption, and subsequent Pb toxicity to birds in general, and woodcock specifically. This review discusses Pb exposure routes, effects of Pb toxicity, and the distribution of Pb in American woodcock and identifies areas for future research in woodcock and other avian species.
... Lead (Pb) exposure is a serious conservation threat to birds [1] because it causes significant behavioral and physiological impairment as well as direct mortality at environmentally-relevant exposures [1][2][3][4]. Although avian Pb exposure has been associated with numerous sources such as Pb-based paints [5], mining [6,7], and fishing tackle [8,9], spent ammunition is often the most widespread source of Pb to scavenging birds [10][11][12][13][14][15][16]. ...
Recreational ground squirrel shooting is a popular activity throughout the western United States and serves as a tool for managing ground squirrel populations in agricultural regions. Belding's ground squirrels (Spermophilus beldingi) are routinely shot in California, Nevada, and Oregon across habitats that overlap with breeding avian scavengers. Ground squirrels shot with lead (Pb)-based bullets may pose a risk to avian scavengers if they consume carcasses containing Pb fragments. To assess the potential risk to breeding avian scavengers we developed a model to estimate the number, mass, and distribution of Pb fragments in shot ground squirrels using radiographic images. Eighty percent of shot carcasses contained detectible Pb fragments with an average of 38.6 mg of Pb fragments. Seven percent of all carcasses contained Pb fragment masses exceeding a lethal dose for a model raptor nestling (e.g. American kestrel Falco sparverius). Bullet type did not influence the number of fragments in shot ground squirrels, but did influence the mass of fragments retained. Beld-ing's ground squirrels shot with .17 Super Mag and unknown ammunition types contained over 28 and 17 times more mass of Pb fragments than those shot with .22 solid and .22 hollow point bullets, respectively. Ground squirrel body mass was positively correlated with both the number and mass of Pb fragments in carcasses, increasing on average by 76% and 56% respectively across the range of carcass masses. Although the mass of Pb retained in ground squirrel carcasses was small relative to the original bullet mass, avian scavenger nestlings that frequently consume shot ground squirrels may be at risk for Pb-induced effects (e.g., physiology, growth, or survival). Using modeling efforts we found that if nestling golden eagles (Aquila chrysaetos), red-tailed hawks (Buteo jamaicensis), and Swainson's hawks (B. swainsoni) consumed shot ground squirrels proportionately to the nestling's mass, energy needs, and diet, 100% of the nestling period would exceed a 50% reduction in delta-aminolevulinic acid dehydratase production threshold, the last 13–27% of the nestling stage would exceed a reduced growth rate threshold, but no nestlings would be expected to exceed a level of Pb ingestion that would be lethal.
... The consumption of virgin plastic granules by 3.8% of Turtle Doves and their presence throughout the three years of study showed an unprecedented case of ingestion of plastic material by wild doves. Until now, the consumption of shot pellets (lead or steel) by doves (Schulz et al. 2002(Schulz et al. , 2006 has been reported but there were no records of plastic ingestion. The plastic granules had rounded forms, which contrasts with the irregular and polygonal forms of grit usually ingested by Turtle Doves. ...
Capsule: The diet of European Turtle Doves Streptopelia turtur in Mediterranean forest contained a large volume of wild plant seed but from a small number of key species. Aims: To determine which seed species are consumed by Turtle Doves in Mediterranean forest areas. Methods: Digestive tract contents were identified and evaluated for 222 Turtle Doves shot by hunters during three consecutive years. Results: Thirty seed species were identified in the diet, but only a few species represented most of the volume and frequency. Wild plant seeds appeared in 65.8% of digestive tracts and showed significant variation between years. Although the main wild seed species consumed each year varied annually, certain species were found in the diet every year in high volume and frequency. Adults showed a more diverse and numerous consumption of wild seeds than did juveniles. Plastic granules were also found in 3.8% of individuals. Conclusion: A greater number of wild seed species was found in the diet in contrast to previous studies performed in farmland. Echium plantagineum and Amaranthus deflexus could be important seed sources for Turtle Doves in Mediterranean forest. Additionally, the herbaceous species found in the diet whose seeds ripen earlier in the season might play an important role in Turtle Dove reproductive performance, since they are frequently the only available food in the first half of the breeding season.
... De plus, chez l'Homme, l'administration de zinc augmente la taille du thymus et le nombre de lymphocytes T , alors que l'exposition au plomb est responsable de la production d'auto-anticorps et diminue l'activité des lymphocytes T ). En modifiant la sécrétion d'hormones de stress tels que les corticoïdes, les métaux traces peuvent également induire une immunosuppression Cory-Slechta et al., 2004;Franceschini et al., 2009;Herring et al., 2012;Schulz et al., 2006;Vyskočil et al., 1990;. Aussi, les métaux traces présents dans l'environnement urbain sont susceptibles de modifier l'immunité des individus. ...
Les métaux traces comme le plomb, le zinc sont essentiellement émis par les activités anthropiques et se retrouvent de ce fait à des concentrations beaucoup plus élevées en milieux urbains qu’en milieux ruraux. Durant ma thèse, j’ai tout d’abord testé les effets écotoxicologiques d’une exposition chronique au plomb et/ou au zinc, deux métaux particulièrement abondants en milieu urbain, chez le pigeon biset (Columba livia). J’ai ainsi pu montrer des effets nocifs du plomb, et bénéfiques du zinc sur l’immunité, le maintien de la corpulence et plusieurs paramètres de la reproduction. Du fait de la variabilité des réponses écophysiologiques des individus, les métaux traces sont susceptibles d’exercer de nouvelles pressions de sélection sur les populations urbaines et favoriser les individus capables de se détoxifier ou de tolérer de fortes concentrations en métaux. Au cours de ma thèse, j’ai mis en évidence le rôle de la mélanine dans la fixation du zinc et du plomb au niveau des plumes. Par ailleurs la coloration mélanique du plumage semblent moduler les effets du plomb et du zinc sur certains paramètres physiologiques, et les juvéniles au plumage davantage mélanique survivent mieux dans un environnement pollué en plomb. Quels que soient les mécanismes sous-jacents (i.e. rôle détoxifiant de la mélanine ou effets pléiotropes associés à sa synthèse), mes résultats soulignent l’avantage sélectif potentiel de la mélanisation du plumage dans un environnement pollué en métaux traces, dont notamment le milieu urbain. Cette étude apporte des réponses essentielles sur l’impact écologique de l’urbanisation et les mécanismes permettant le maintien du polymorphisme de coloration mélanique du plumage, et plus largement des phanères.
... Lead is a naturally occurring element that can be toxic to humans and wildlife (Ona et al. 2006;Rattner et al. 2008). Numerous studies have documented that lead is a direct, contributing factor to wildlife mortality and secondary poisoning (Fisher, Pain, and Thomas 2006;Minnesota Department of Natural Resources [MNDNR] 2006;Schulz et al. 2006;Kimmel and Tranel 2008;Rattner et al. 2008). Lead shot remains on the landscape, where it is ingested as grit by birds directly; secondary consumption occurs when carcasses of species hunted with lead are consumed by raptors and other scavengers. ...
Shot from hunting adds toxic lead to environments worldwide. Existing lead shot regulations have been instituted with little understanding of hunter beliefs and attitudes. This study applied the Theory of Reasoned Action, using a multilevel, multivariate approach, to clarify how positive and negative beliefs relate to attitudes about a ban on lead shot. Structure coefficients and commonality analysis were employed to further examine relationships between beliefs and attitudes. Results suggest that while both positive and negative outcomes influence attitudes, positive outcomes were more influential for supporters and negative beliefs for opposers. Management may need to focus on the results from hunters who indicated that they would be unlikely to support a ban, as these hunters include those who may actively oppose additional efforts to regulate lead.
... Shot retention has been reported in eagles that have succumbed to lead poisoning in the wild (e.g., 77 shot recovered in one eagle, Jacobson et al. 1977 ; Fig. 6 ). The variability in shot retention seen here is consistent with that seen in other species that ingest lead shot, which may erode or pass through the gut before death occurs (Roscoe et al. 1979 ;Schulz et al. 2006 ). ...
There are multiple sources of lead in the environment. However, scientific evidence points to spent lead ammunition as the most frequent cause of lead exposure and poisoning in scavenging birds in the United States. Despite the ban on its use for waterfowl hunting, lead ammunition is still widely used for other hunting and shooting activities. Therefore, it can remain on the landscape in carcasses not retrieved and in discarded offal piles. Carcasses and gut piles can be attractive food sources to scavenging birds that can ingest bullet fragments or shot while feeding. Scavenging birds may be particularly vulnerable to exposure and effects of lead due to their foraging strategies and food preferences, physiological processes that facilitate the absorption of lead, and demographic traits. Numerous lines of evidence support ammunition as the source of exposure in the majority of lead poisoned scavenging birds and include the recovery of ingested lead fragments or shot from exposed birds, observations of birds feeding on contaminated carcasses, isotopic signatures of lead in tissue that match that found in ammunition, patterns of mortality coincident with hunting seasons, and the lack of abundant evidence for other lead sources. Lead can be replaced in ammunition by alternative metals that are currently available and present limited environmental threats.
... Like all birds, sharp-tailed grouse are susceptible to lead poisoning. While it has not been diagnosed in sharptails, poisoning by spent lead shot has been documented in ruffed grouse, chukar, gray partridge (Perdix perdix), ring-necked pheasant, and quail (Callipepla squamata, Colinus virginianus; Locke and Friend 1992, Walter and Reese 2003, Fisher et al. 2006, Schulz et al. 2006, Pain et al. 2009). ...
... For example, multiple field studies of wild mourning doves (Zenaida macroura) and areas used frequently by dove hunters have assessed elevated lead exposure and occurrence of lead pellets in soils (Locke and Bagley 1967, Lewis and Legler 1968, Best et al. 1992, Schulz et al. 2002. Additionally, dosing experiments with captive mourning doves have addressed the susceptibility of these birds to lead toxicosis (Buerger et al. 1986, Schulz et al. 2006. Nonetheless, available literature on elevated lead exposure in upland birds other than mourning doves often consists simply of documenting individuals with ingested lead pellets (Walter andReese 2003, Butler 2005), or diagnosing that a bird has succumbed to lead poisoning as a result of lead ingestion and absorption (Keymer andStebbings 1987, Lewis andSchweitzer 2000). ...
The use of lead ammunition has generated much debate because lead is toxic and elevated lead exposure is documented in >130 wildlife species. We expanded on prior reports of ingested lead in chukars (Alectoris chukar) to assess lead exposure at greater spatial and temporal extents. Our specific objectives concerning lead exposure in chukars from northwestern Utah, USA (approx. 49,000 km2) were to: 1) approximate a threshold for background versus elevated lead exposure; 2) investigate spatial and temporal variation of lead exposure; and 3) assess the utility of combining frequencies of ingested gizzard lead and elevated liver lead to estimate lead ingestion rates. We obtained hunter and volunteer-harvested chukars collected during July–January, 2003–2011. Using liver lead residues from wild chukars, we estimated a threshold of 1 μg/g wet weight to separate background versus elevated lead exposure for our data set. For wild chukars, we documented elevated lead exposure (ingested gizzard lead or elevated liver lead) in 5 counties and 8 mountain ranges in years 2003–2007. We estimated lead ingestion rates of 9.3% (43 of 461) using ingested gizzard lead and 8.3% (10 of 121) employing elevated liver lead (≥1 μg/g wet weight), respectively. These frequencies were respectively 1.5% and 2.5% less than the combined frequency of ingested gizzard lead and elevated liver lead (10.8%; 52 of 481). Our observed rates of elevated lead exposure were among the highest in the literature for upland birds, suggesting that chukars in northwestern Utah risk lead poisoning. These results corroborate previous findings identifying elevated lead exposure as an issue affecting non waterfowl avian species. © 2015 The Wildlife Society.
... The use of daily lottery systems for allocating hunting pressure throughout a season has been used extensively for managing waterfowl harvests on public wetlands in Missouri (Baskett 1993), and we expected lottery systems to similarly affect the number of hunts and doves harvested in our study. Simultaneously, nontoxic-shot regulations are involved in a larger debate about the ecological impacts of lead poisoning beyond wetlands (Schulz et al. 2006(Schulz et al. , 2007aWatson et al. 2009). However, the simultaneous use of these regulations by participating areas precluded evaluation of the importance and effects of the 2 regulation types and leaves questions surrounding them unresolved. ...
Mourning dove (Zenaida macroura) management efforts have focused on reducing uncertainties in harvest management at national and regional scales, but there remains considerable interest in issues related to local, intensively managed areas. Our objective was to evaluate effects of different local management strategies, including field management and regulations, and weather, on the number of hunts and the number of doves harvested annually. We collected harvest information from dove hunters, and area management characteristics from wildlife managers on 9 public hunting areas in Missouri, USA from 2005 to 2009. Number of hunts on an area was best explained by number of hectares of crop on the area; however, acreage above 50 ha offered limited increases in the number of hunts on a site. The most supported model for the number of doves harvested contained a positive effect of acreage of sunflowers (Helianthus annuus) in good or excellent condition. This model was followed by a closely competing model reflecting increases in the number of doves harvested when an area used daily lottery and shot-type restrictions; however, complete overlap between these 2 regulations prevented separation of their individual effects. To manipulate hunting opportunities and harvest levels in Missouri, managers can be most effective by controlling hectares and condition of managed croplands, especially sunflowers. However, further work is needed to assess the relative impacts of lottery regulations and nontoxic-shot restrictions on dove harvest. © 2011 The Wildlife Society.
... Shot from hunting adds toxic lead to environments worldwide. Numerous studies have documented that lead shot is a direct, contributing factor to wildlife mortality and secondary poisoning (Gay 2004, Fisher et al. 2006 2006b, Schulz et al. 2006, Kimmel and Tranel 2008, Rattner et al. 2008). More than 100 species of upland birds, waterfowl, and raptors have been found to have ingested lead shot. ...
Lead shot from hunting adds the toxic metal to environments worldwide. The United States banned lead shot for hunting waterfowl in 1991 and 26 states have lead shot restrictions beyond those mandated for waterfowl hunting. The Minnesota Department of Natural Resources (MDNR) was interested in studying hunter attitudes about expanded restrictions on the use of lead shot for hunting small game to understand what communication strategies might increase public support for potential restrictions on lead shot. We mailed messages about lead shot, including 1,200 control messages and 400 of each of 9 treatment messages, and surveys to 4,800 resident small game hunters. We compared attitudes and intentions related to a possible ban among control and treatment groups. Compared to the control message, all treatment messages elicited more positive attitudes and intentions to support a ban. A basic factual message, messages with references to Ducks Unlimited, and a first-person narrative message generated the strongest support for a ban. Results also demonstrated a substantial relationship between the use of lead shot and response to persuasive messages supporting a ban.
... Shot from hunting adds toxic lead to environments worldwide. Numerous studies have documented that lead shot is a direct, contributing factor to wildlife mortality and secondary poisoning (Gay 2004, Fisher et al. 2006, Minnesota Department of Natural Resources [MDNR] 2006b, Schulz et al. 2006, Kimmel and Tranel 2008, Rattner et al. 2008). More than 100 species of upland birds, waterfowl , and raptors have been found to have ingested lead shot. ...
Lead shot from hunting adds the toxic metal to environments worldwide. The United States banned lead shot for hunting waterfowl in 1991 and 26 states have lead shot restrictions beyond those mandated for waterfowl hunting. The Minnesota Department of Natural Resources (MDNR) was interested in studying hunter attitudes about expanded restrictions on the use of lead shot for hunting small game to understand what communication strategies might increase public support for potential restrictions on lead shot. We mailed messages about lead shot, including 1,200 control messages and 400 of each of 9 treatment messages, and surveys to 4,800 resident small game hunters. We compared attitudes and intentions related to a possible ban among control and treatment groups. Compared to the control message, all treatment messages elicited more positive attitudes and intentions to support a ban. A basic factual message, messages with references to Ducks Unlimited, and a first-person narrative message generated the strongest support for a ban. Results also demonstrated a substantial relationship between the use of lead shot and response to persuasive messages supporting a ban. ß 2012 The Wildlife Society.
... Within the context of making policy, decision makers must balance the relative importance of multiple data streams, and simultaneously assign relative certainty to the available knowledge (Reitz et al. 2007). As previously demonstrated, we know with certainty (1) that lead is a well established broadspectrum ecological poison (Sanderson and Bellrose 1986, Eisler 1988, Kendall et al. 1996, (2) hunters can deposit relatively large amounts of lead shot on areas that are popular Mourning Dove (Zenaida macroura) feeding sites (Lewis and Legler 1968, Best et al. 1992, Schulz et al. 2002, (3) a certain proportion of the dove population feed on these sites and ingest lead pellets (Otis et al. 2008, Franson et al. 2009, and (4) virtually all doves that ingest pellets succumb to the direct or indirect effects of lead poisoning (Schulz et al. 2006. Conversely, there is considerable uncertainty about the (1) relationship between lead pellet availability and pellet ingestion on areas with different levels of hunter and bird use, (2) uncertainty about the actual proportion of the population impacted by lead poisoning and whether that proportion is significant, (3) uncertainty about the impacts of other surface-feeding seed-eating songbirds and upland game-birds, (4) uncertainty about the eventual fate of doves dying of lead poisoning (e.g., consumption by scavengers), and (5) uncertainty about how the increased cost of nontoxic shot ammunition may negatively influence future small-game hunter participation rates. ...
... Kendall and Scanlon (1982a, b) likewise documented Pb in the blood in mourning doves and rock doves in Virginia. Schulz et al. (2006) conducted a controlled acute Pb toxicity study on mourning doves by dosing 157 birds with 2-24 Pb pellets. These authors reported a strong correlation between survival and the number of pellets administered. ...
Avian wildlife species commonly ingest lead (Pb) spent shot or bullet fragments as grit or mistakenly as food. In previous studies in our laboratory and others, the toxicity varied based on the diet as well as type and quantity of Pb ingested. In the current study, domestic pigeons were gavaged with 1, 2, or 3 Pb pellets and then followed with weekly radiographs and blood physiologic endpoints for 28 days. Pellet retention decreased by roughly 50 % per week as pellets were either absorbed or excreted, except for week 4 where pellet number no longer was diminished. Size of retained pellets visually decreased over retention time. Birds dosed with a single #9 pellet showed mean blood Pb levels over 80 times higher than those of the controls, verifying Pb pellet absorption from the gut. A single Pb pellet also reduced plasma δ-aminolevulinic acid dehydratase (δ-ALAD) activity by over 80 % compared to controls, suggesting the potential for population injury in Pb pellet-exposed pigeons.
... The MBCA was used in Canada in 1999 to effect the same transition throughout Canada. At the time of passage, the regulations were applied only to the hunting of waterbirds because this was the area of greatest primary and secondary lead poisoning that federal authorities wished to address (USFWS 1986 The case that Mourning Doves ingest lead shot and succumb readily to lead poisoning has been made (Lewis and Legler 1968, Schultz et al. 2002, 2006b, including the suggestion that the impacts from recreational hunters may be greater than once believed (Schultz et al. 2002). In a later paper Schultz et al. (2006b) advocated that a national nontoxic shot regulation be implemented for Mourning Doves, based on the numbers of doves suspected to be afflicted by lead poisoning and their susceptibility to ingested lead shot. ...
This paper addresses the policy and legislative considerations for moving North American society towards the use of nontoxic shot and bullets for all types of hunting and shooting. Progress in one or more areas of lead use reduction by society has not facilitated transitions in other areas of lead use, and the two solitudes of conservationists (anti-lead) and hunters (pro-lead) is real. Regulators must emphasize the gains in wildlife to both constituencies that will attend adoption of nontoxic products. Sixteen years of nontoxic shot use in waterfowl hunting is the most cost-effective conservation tool to date in conserving waterfowl populations. Similar savings could be expected from the use of lead-free shot such as for hunting migratory doves and upland birds. New ballistic materials are available for use on upland species, and in all gauges of modern and old guns. Industry has adapted materials for use in rifle cartridges of varying calib-ers. Although industry has responded well to the quest for nontoxic ballistic materials, industry requires en-forceable regulations to create and assure the market demand for their products. Different policy and legis-lative options are presented. Regulatory progress would best be based on precedents under the Migratory Bird Treaty Act, entailing its application to species that fall under federal jurisdiction. The use of this Act would constitute the rationale for Canada to implement similar provisions for the same species under its Migratory Birds Convention Act. Individual states and provinces could then be petitioned to adopt com-plementary measures for hunting upland bird and mammalian species that fall under their jurisdiction. The development of nontoxic bullets for big game hunting could also be applied to the smaller caliber lead bul-lets used for small mammals, because they constitute a source of secondary lead poisoning of carrion feed-ers. Any legislation developed to phase out all lead use must be harmonized between the USA and Canada, and among the states and provinces to ensure consistency of regulation and its application. Progress in this task has to be based on the premise that use of nontoxic materials benefits all wildlife, the sport of proac-tive hunters, and society that experiences less lead in the environment. Received 16 May 2008, accepted 6 August 2008. THOMAS, V. G. 2009. The policy and legislative dimensions of nontoxic shot and bullet use in North Amer-ica.
... Sileo et al. (1973) reported 25–45% reduction in body weight followed by death for Canada Geese (Branta canadensis) dosed with lead shot. Death as a result of poisoning from lead shot has been demonstrated for many species, including doves (Schulz et al. 2006a, Schulz et al. 2007), Mallards (Finley and Dieter 1978, Anderson and Havera 1989), and Canada Geese (Cook and Trainer 1966). Fisher et al. (2006) suggested that behavioral changes resulting from lead poisoning might influence susceptibility to predation, disease, and starvation, which increases the probability of death. ...
The Minnesota Department of Natural Resources (MDNR) has been investigating non-toxic shot regulations for upland small game hunting because there is considerable evidence that the use of lead ammunition impacts the health of wildlife, the environment, and humans. In 2006 MDNR established a Non-toxic Shot Advisory Committee (NSAC) to provide citizen input on restricting lead shot for small game hunting. To support the NSAC discussions, we summarized available literature regarding lead am-munition and its effects on wildlife, the environment, and human health. This literature review includes more than 500 citations on lead and non-toxic ammunition related issues worldwide and summarizes stud-ies regarding ingestion of lead shot, bullets, and fragments by wildlife species and the impacts of lead poi-soning on wildlife, the environment, and humans. We found over 130 species of animals (including upland birds, raptors, waterfowl, and reptiles) have been reported in the literature as being exposed or killed by in-gesting lead shot, bullets, bullet fragments, or prey contaminated with lead ammunition. The impacts of in-gested lead on wildlife included decreased survival, poor body condition, behavioral changes, and impaired reproduction. We found 15 recent studies that demonstrated the impacts of lead ammunition on human health. Studies in Canada, Greenland, and Russia linked lead shot found in game animals to higher levels of lead in people who eat those game animals, and recent evidence shows that meat far from entry wounds may contain lead fragments. Effective non-toxic alternatives to lead shot are available, and at costs compa-rable to lead. The results of our review demonstrate the effects of lead ammunition on wildlife, the envi-ronment, and human health and support the need for the use of non-toxic alternatives to lead ammunition.
... Lead pellet ingestion rates for hunter-killed mourning doves vary from <1.0 to 6.5% depending on locale (Conti, 1993;Mirarchi and Baskett, 1994;Kendall et al., 1996;Schulz et al., 2007). Considerable information exists demonstrating that dove hunters deposit large quantities of spent lead shot around favorable hunting locations, some proportion of doves ingest lead pellets while feeding on hunted fields, and most doves ingesting lead pellets eventually die from the immediate or secondary effects of lead poisoning (Schulz et al., 2006). Other wildlife species might similarly ingest lead and die. ...
... As regards the indirect leukocytic measures of immune function, nestling survival was negatively correlated with heterophile hemoconcentration in pied flycatchers (Lobato et al. 2005) and H/L ratio in great tits (Nadolski et al. 2006). These leukocytic parameters were also associated with local survival in adult great tits (Kilgas et al. 2006b but see Hõrak & Ots 1998 Dubiec et al. 2005), eiders (Somateria mollissima; Hanssen 2004), mourning doves (Zenaida macroura; Schultz et al. 2006) and wood storks (Mycteria americana; Hylton et al. 2006). To summarise, in this study I found that immune function of great tit nestlings was affected by their growth conditions and also that differences in nestling survival between broods were related to immune parameters. ...
Lead poisoning is an important global conservation problem for many species of wildlife, especially raptors. Despite the increasing number of individual studies and regional reviews of lead poisoning of raptors, it has been over a decade since this information has been compiled into a comprehensive global review. Here, we summarize the state of knowledge of lead poisoning of raptors, we review developments in manufacturing of non‐lead ammunition, the use of which can reduce the most pervasive source of lead these birds encounter, and we compile data on voluntary and regulatory mitigation options and their associated sociological context. We support our literature review with case studies of mitigation actions, largely provided by the conservation practitioners who study or manage these efforts. Our review illustrates the growing awareness and understanding of lead exposure of raptors, and it shows that the science underpinning this understanding has expanded considerably in recent years. We also show that the political and social appetite for managing lead ammunition appears to vary substantially across administrative regions, countries, and continents. Improved understanding of the drivers of this variation could support more effective mitigation of lead exposure of wildlife. This review also shows that mitigation strategies are likely to be most effective when they are outcome driven, consider behavioural theory, local cultures, and environmental conditions, effectively monitor participation, compliance, and levels of raptor exposure, and support both environmental and human health.
Lead (Pb) pollution poses great threats to mammals including human and it is also hazardous to bird life. In this study, RNA sequencing analysis was employed to examine the molecular responses to lead exposure in the liver of a toxicological model species Japanese quails. Female birds were exposed to 0, 50, 500 and 1000 ppm waterborne Pb for 49 days. The results showed that hepatic microstructure was damaged under lead exposure featured by sinusoids dilation and irregularity as well as cell necrosis. Moreover, ultrastructural injury in the liver including mitochondrial swelling and vacuolization as well as nuclear deformation was induced by lead exposure. Lead exposure also caused the decrease of lipid droplets in the liver by oil red O staining. In addition, liver transcriptomic analysis revealed that molecular signaling and functional pathways were disrupted by lead exposure. Meanwhile, the expression of genes involved with hepatic glycerophospholipids metabolism of triglyceride synthesis and lipid transport of triglyceride transfer was significantly down-regulated by lead exposure. Moreover, the up-regulation of genes associated with fatty acid oxidation and the down-regulation of genes related with fatty acid synthesis were caused by lead exposure. The present study implied that lead induced liver malfunction and bird health risks through histopathological damages, molecular signaling disruption, genetic expression alteration and triglyceride metabolism disturbance.
Hunting is a popular activity but continued use of lead ammunition poses risks to wildlife and human health. To inform adoption of the voluntary use of nonlead ammunition, natural resource professionals were surveyed to understand their attitudes about threats to bald eagles, lead poisoning in bald eagles, human health risks from lead bullet fragments in venison, use of nonlead hunting ammunition, and socio-economic nonlead ammunition factors. Differences were examined by hunter status, ammunition type used, and intentions to use nonlead ammunition. Of participants surveyed, 61.0% were hunters and 39.0% nonhunters, with 59.5% of hunters using lead ammunition and 40.5% using nonlead. Concurrently, 68.5% of hunters reported likely intentions to continue using nonlead or convert to nonlead in the future, while 31.5% reported nonlead use was unlikely. Also, some hunters currently using nonlead ammunition indicated they would unlikely continue using nonlead (17.8%). Nonhunters agreed more strongly than hunters regarding general mortality threats to bald eagles. Additionally, nonhunters, hunters using nonlead, and likely nonlead users more strongly agreed about threats of lead exposure to eagles than their counterparts. Nonhunters and likely nonlead users also more strongly agreed than hunters and unlikely nonlead users about the human health risks of lead ammunition and about shooting characteristics of nonlead. Finally, nonhunters and nonlead users agreed more strongly than their counterparts about the socio-economic factors of using nonlead ammunition. Understanding natural resource professional hunters’ attitudes may help with audience segmentation when designing future nonlead outreach messages.
Management implications
Among natural resource professionals, hunters are important in nonlead outreach programs, but results suggest nonhunters have greater understanding and awareness of the issues related to the effects of lead ammunition on the environment. Attitudes about lead poisoning and nonlead ammunition overlapped between hunters and nonhunters, suggesting the two groups are not mutually exclusive. A substantial proportion of nonlead hunters are likely to continue using it, but some indicated they might switch back to lead ammunition, suggesting a need to reinforce initial behavior. Hunters and nonhunters are both important target audiences for education and outreach programs.
This chapter reviews the available literature for clinical pathology of columbiformes. The avian order Columbiformes includes two families,the family Columbidae, and the family Pteroclididae. Columbiforme species native to the UnitedStates include the mourning dove,white‐winged dove, band‐tailed pigeon, white‐crowned pigeon, and Inca dove. Blood parasites are commonly observed on blood smear evaluation of wild columbiformes. Blood gases and blood lactate in pigeons in normal states and in response to changes in temperature, simulated altitude, and flight distance have been studied. In Europe, more than 100human cases associated with contact with feral pigeonshave been reported. Mycobacteriosis is a challenging disease to diagnose and treat in pigeons. Salmonella enterica serotype Typhimurium causes paratyphoid in pigeons. Pigeon paramyxovirus serotype 1 (PPMV‐1) affects columbiformes and can also infect poultry. Commercial vaccines against PPMV‐1 are available for pigeons.
Lead poisoning of scavenging raptors occurs primarily via consumption of game animal carcasses containing lead, which peaks during fall firearm hunting seasons. We hypothesized that snowfall would mitigate exposure by concealing carcasses. We categorized blood lead level (BLL) for a subsample of Bald Eagles (Haliaeetus leucocephalus) from the Upper Mississippi River Valley and described BLL with respect to age, sex, and snowfall. We captured Bald Eagles overwintering in the Upper Mississippi River Valley (n=55) between December 1999 and January 2002. Individual BLL ranged from nondetectable to 335 μg/dL, with 73% of the samples testing positive for lead exposure from point sources. Eagle BLL did not significantly differ between age or sex, but levels were higher immediately following the hunting season, and they were lower when the previous month's snowfall was greater than 11 cm. This study suggests a window of time between the white-tailed deer (Odocoileus virginianus) hunting season and the onset of snow when the population experienced peak exposure to lead. Combining these findings with existing research, we offer a narrative of the annual lead exposure cycle of Upper Mississippi River Valley Bald Eagles. These temporal associations are necessary considerations for accurate collection and interpretation of BLL.
Lead is toxic to all vertebrate species and ingestion of lead ammunition has been reported in >130 avian species. Research has primarily focused on the effects and exposure of spent lead shot on waterfowl with little information about effects on upland game species, such as ring-necked pheasant (Phasianus colchicus). We collected 1,450 soil samples to estimate the availability of lead shot on 2 licensed shooting preserves in South Dakota, USA, 2012–2013. We concurrently collected gizzards from 660 hunter-harvested wild male pheasants from the shooting preserves and compared lead ingestion rates with those of 1,301 gizzards collected from nonpreserve areas. Spatial modeling showed the distribution of spent lead shot was associated with the systematic hunting pattern of each study site and, to a lesser extent, land-use type. Prevalence of ingested lead shot was 4.9 times greater for birds harvested on shooting preserves (3.9%, 95% CI = 2.7–5.7%) when compared with nonpreserve areas (0.8%, 95% CI = 0.4–1.4%) where lead shot availability was presumed less. Wild pheasants inhabiting areas of artificially high hunting intensity and lead deposition are at elevated risk of lead exposure and poisoning, although the consequences of lead ingestion in wild pheasants are unknown.
Wildlife diseases have become increasingly important recently due to their effect upon human health, veterinary medicine, wildlife, and conservation biology. Gary Wobeser's successful book from 1994 has been completely updated and enlarged in a new second edition. An in-depth overview of the available techniques for the investigation and management of disease in free-ranging animals is provided. The subjects are illustrated with examples drawn from around the world, with emphasis on the special requirements involved in working with wild animals. Techniques are assessed critically with regard to their efficacy and effectiveness. The book draws on the author's training as a wildlife biologist and veterinarian and his experience over four decades with wildlife disease. From the reviews of the first edition ". has done an admirable job of outlining the problems associated with diagnosing and controlling disease in wildlife populations. The author has commendably presented a difficult topic and has shown that the usually successful approach to treating disease in domestic animals is extremely difficult and rarely successful in wildlife populations. I recommend this book to all who are looking for an introduction to the investigation and managment of disease in wildlife." (Canadian Veterinary Journal)". the author has made a major contribution to the field by providing a conceptual framework for wildlife disease investigations and by highlighting the inadequacies that often exist. His willingness to challenge dogma and constructively present perspectives based on a combination of extensive literature review, personal experiences, and beliefs is one of the values of this well organized and easy to read publication. this publication should be read by biologists, administrators, and disease specialists having responsibility for combatting disease in populations of free-living wildlife." (Journal of Wildlife Diseases)
Contamination at shooting range is increasingly of concern due to the accumulation of lead from bullet fragments in soil. This study investigates the degree of contamination in and around the Ibadan military shooting range, Nigeria. A total of 220 soil samples were collected in and around the range. At the core-range area, average Pb (5680 ± 2700 mg kg) level in topsoil at the berm was significantly higher than other locations representing 280 times the background. Lead levels at the surrounding vicinity were similar to the control sites. Parametric t-test (95% confidence limit) showed no significant difference in Pb levels between the topsoil and subsoil. Concentrations of Cu and Cd were similarly higher at the berm. Inter-element correlation coefficient was generally high (0.70–0.93) except for Ni and Cr. This indicates that Ni and Cr were not influenced by shooting activities. Principal component analysis showed that metal levels at the berm, target basement, 100 m and 200 m firing lines accounted for 74.7% of the overall metal load of the soil. Correspondent analysis gave the degree of contamination in the order of Pb > Cd > Cu > Ni > Cr. There was evidence of contamination around the berm. Mitigation measures are required to minimize the current level of contamination.
Previous field studies of hunter-harvested mourning doves (Zenaida macroura) have reported the percentage of birds with ingested lead shot as 0.2–6.5%. To reduce the uncertainty concerning the number of doves that ingest shot, we conducted an experiment to test the proportion of mourning doves that ingested lead shot on the bare soil of a disked field (typical of a managed dove field) to simulate more natural feeding conditions. In each of 3 treatment groups of 80 birds, we exposed 35 birds to low-density lead shot (1.5 million shot/ha), and35 birds to high-density lead shot (29.5 million shot/ha), and 10 birds served as controls (no shot). We dosed 5 positive control birds with 2 lead shot each in trials 2 and 3. We scattered lead shot and mixed seed on the loosely packed soil of treatment cages and after 4 days of exposure, 2.9% of doves voluntarily ingested ≥1 lead shot. The proportion of birds that ingested shot when exposed to the high-density shot treatment (4.9%) was not different (P = 0.098) from that of the low-density shot treatment (1.0%). Lead concentrations in liver, kidneys, and blood reached maxima of 94.402 ppm, 346.033 ppm, and 13.883 ppm wet mass, respectively. Differences in delta-aminolevulinic acid dehydratase (ALAD) activity, packed cell volume, and heterophil:lymphocyte ratio (H:L) were greater posttreatment in doves that had ingested shot than in those that did not. The risk posed to mourning doves from lead shot ingestion can be reduced by banning lead shot on management areas or dove fields or disking fields after hunting season to reduce shot availability. © 2011 The Wildlife Society.
Lead as one part of heavy metals group pose a detrimental risk to human health and the environment due to its toxicity, even exposure to minuscule quantities can be life threatening. Levels of lead are not stable in the environment and vary according to industrial production, urbanization, climate changes and many other factors. It is not surprising that rapid, sensitive and simple analytical determination of metal ions in environment is very important. Electrochemical techniques are one of the best methods for detecting metals due to their low cost, high sensitivity and portability. The aim of this study was to compare various microwave digestion procedures for lead(II) ions isolation in vultures samples of vultures available in very small quantities (5-20 mg) followed by differential pulse voltammetry as a detection method. We found that the combination of (65%, w/w) HNO 3 + (30%, w/w) H 2 O 2 is advantageous for the resulting electrochemical response. To determine the effect of mineralization on the height of the lead(II) ions peak, eight different mineralization programs were tested. It clearly follows from the results obtained that 200 W power for 30 min. is the most optimal for mineralisation Int. J. Electrochem. Sci., Vol. 6, 2011 5981 of vultures' samples. In the following part of the study, the influence of four different locations of samples in the rotor of used microwave system was investigated. Under the optimized conditions, samples of blood and eggs from vultures poisoned by lead(II) ions were prepared and electrochemically analysed. Three types of working electrodes as hanging mercury drop electrode, carbon paste electrode and screen printed electrode made of multi-walled nanotubes (MWNTs) were employed for this purpose. All three electrodes were sensitive enough to be used for analysis of real samples. Based on the results obtained it clearly follows that the level of lead(II) ions in intoxicated vultures ranged from 1 to 5 µg/ml of blood. In addition, it was found that the lead toxicosis was diagnosed in all vultures properly. Besides lead, cadmium was determined electrochemically and Ca, Mg, Fe, Zn and Cu spectrometrically. Besides the content of lead(II) and cadmium(II) ions, we determined metallothionein as a protein connected with protection of vertebrates against metal ions using differential pulse Brdicka reaction. The level of MT was determined as 1.82 ± 0.31 µg/mg of proteins in the intoxicated vultures compared with the control group 0.71 ± 0.19 µg/mg of proteins, which means more than a 250% increase of MT levels.
ABSTRACT The scientific evidence that California condors (Gymnogyps californianus) are frequently sickened and killed by lead poisoning from spent ammunition supports the conclusion that current levels of lead exposure are too high to allow reintroduced condors to develop self-sustaining populations in the wild in Arizona and, by inference, in California. The evidence for lead poisoning and its source comes from the following sorts of data: 1) 18 clinical necropsies revealing high levels of lead in body tissues and (or) presence of lead shotgun pellets and bullet fragments in digestive tracts; 2) moribund condors showing crop paralysis and impending starvation with toxic levels of lead in their blood; 3) widespread lead exposure among free-flying condors, many with clinically exposed or acute levels; 4) temporal and spatial correlations between big game hunting seasons and elevated lead levels in condors; and 5) lead isotope ratios from exposed condors showing close similarity to isotope ratios of ammunition lead but isotope ratios in less exposed condors being similar to environmental background sources, which are different from ammunition lead. Simple population models reveal harmful demographic impacts of unnatural mortality from lead on population trajectories of reintroduced condors. Recent innovations in the manufacture of nonlead shotgun pellets and bullets with superior ballistics now provide for a simple solution to the problem of lead ingestion by condors, many other species of wildlife, and human beings: substitute nontoxic forms of ammunition for traditional lead-based ammunition. The substitution of nontoxic ammunition would be highly efficacious for hunting, economically feasible, and the right thing to do.
The manufacture of projectiles for ammunition used in hunting and target shooting, and for terminal tackle (sinkers and jigs)
used in recreational angling, comprises a significant continuing commercial use of lead, and a major source of lead deposition
into the environment. Thousands of tons of metallic lead are deposited into the North American environment annually from hunting,
target-shooting, and recreational angling activities. Numerous symposia and conferences have been held, and hundreds of research
papers have been published, addressing lead exposure and toxicosis in wildlife from ingestion of spent lead ammunition and
fishing sinkers, but the transition (regulatory or otherwise) to nontoxic substitutes has been slow, impeded in large part
by the resistance of hunters, anglers, and their representative organizations to adopt nontoxic products, rather than an inability
of the ammunition and tackle industries to manufacture and distribute such products. Here, we present a historical analysis
of the interactions between environmental science and regulatory policy development with respect to the use of lead in recreational
shooting and angling in North America.
ABSTRACT.—Because the relationship between lead pellet availability and ingestion by
mourning doves (Zenaida macroura) remains uncertain, we conducted an experiment to
determine if doves held in captivity freely ingest lead shotgun pellets, investigate the
relationship between pellet density and ingestion and monitor physiological impacts of doves
ingesting pellets. We conducted two trials of the experiment with ,60 doves per trial. We
randomly assigned 10 doves to one of six groups per trial; 10, 25, 50, 100, 200 pellets mixed
with food and a control group with no pellets. We monitored ingestion by examining x-rays of
doves 1-d post-treatment and monitored the effects of lead ingestion by measuring
heterophil:lymphocyte (H:L) ratios, packed-cell volume (PCV), blood lead, liver lead and
kidney lead. Pooled data from both trials showed 6 of 117 (5.1%) doves ingested lead pellets.
Two mourning doves ingested multiple lead pellets in each of the treatments containing
a mixture of 25, 100 and 200 lead pellets and food. Doves ingesting lead pellets had higher
blood lead levels than before treatment (P = 0.031). Post-treatment H:L ratios, however, were
not different compared to pre-treatment values (P = 0.109). Although post-treatment PCV
decreased for four of six doves ingesting lead pellets, overall they were not lower than their
pre-treatment values (P = 0.344). Liver (P < 0.0001) and kidney (P = 0.0012) lead levels for
doves ingesting pellets were higher than doves without ingested pellets. Our lead pellet
ingestion rates were similar to previously reported ingestion rates from hunter-killed doves
and our physiological measurements confirm earlier reports of a rapid and acute lead
toxicosis. Similar to previous field research, we did not observe a relationship between pellet
density in the food and ad libitum pellet ingestion. Although one approach would be to ban
lead shot for mourning dove hunting on managed public hunting areas, further research is
necessary to ensure that policy development and implementation have a consensus among
stakeholders.
ABSTRACT.—Because the relationship between lead pellet availability and ingestion by
mourning doves (Zenaida macroura) remains uncertain, we conducted an experiment to
determine if doves held in captivity freely ingest lead shotgun pellets, investigate the
relationship between pellet density and ingestion and monitor physiological impacts of doves
ingesting pellets. We conducted two trials of the experiment with ,60 doves per trial. We
randomly assigned 10 doves to one of six groups per trial; 10, 25, 50, 100, 200 pellets mixed
with food and a control group with no pellets. We monitored ingestion by examining x-rays of
doves 1-d post-treatment and monitored the effects of lead ingestion by measuring
heterophil:lymphocyte (H:L) ratios, packed-cell volume (PCV), blood lead, liver lead and
kidney lead. Pooled data from both trials showed 6 of 117 (5.1%) doves ingested lead pellets.
Two mourning doves ingested multiple lead pellets in each of the treatments containing
a mixture of 25, 100 and 200 lead pellets and food. Doves ingesting lead pellets had higher
blood lead levels than before treatment (P 5 0.031). Post-treatment H:L ratios, however, were
not different compared to pre-treatment values (P 5 0.109). Although post-treatment PCV
decreased for four of six doves ingesting lead pellets, overall they were not lower than their
pre-treatment values (P 5 0.344). Liver (P , 0.0001) and kidney (P 5 0.0012) lead levels for
doves ingesting pellets were higher than doves without ingested pellets. Our lead pellet
ingestion rates were similar to previously reported ingestion rates from hunter-killed doves
and our physiological measurements confirm earlier reports of a rapid and acute lead
toxicosis. Similar to previous field research, we did not observe a relationship between pellet
density in the food and ad libitum pellet ingestion. Although one approach would be to ban
lead shot for mourning dove hunting on managed public hunting areas, further research is
necessary to ensure that policy development and implementation have a consensus among
stakeholders.
Birds are exposed to Pb by oral ingestion of spent Pb shot as grit. A paucity of data exists for retention and clearance of these particles in the bird gastrointestinal tract. In the current study, northern bobwhite quail (Colinus virginianus) were orally gavaged with 1, 5, or 10 Pb shot pellets, of 2-mm diameter, and radiographically followed over time. Blood Pb levels and other measures of toxicity were collected, to correlate with pellet retention. Quail dosed with either 5 or 10 pellets exhibited morbidity between weeks 1 and 2 and were removed from further study. Most of the Pb pellets were absorbed or excreted within 14 d of gavage, independent of dose. Pellet size in the ventriculus decreased over time in radiographs, suggesting dissolution caused by the acidic pH. Birds dosed with one pellet showed mean blood Pb levels that exceeded 1,300 µg/dl at week 1, further supporting dissolution in the gastrointestinal tract. Limited signs of toxicity were seen in the one-pellet birds; however, plasma δ-aminolevulinic acid dehydratase (d-ALAD) activity was persistently depressed, suggesting possible impaired hematological function.
Mourning dove (Zenaida macroura) hunting is becoming increasingly popular, especially in managed shooting fields. Given the possible increase in the availability of lead (Pb) shot on these areas, our objective was to estimate availability and ingestion of spent shot at the Eagle Bluffs Conservation Area (EBCA, hunted with nontoxic shot) and the James A. Reed Memorial Wildlife Area (JARWA, hunted with Pb shot) in Missouri. During 1998, we collected soil samples one or 2 weeks prior to the hunting season (prehunt) and after 4 days of dove hunting (posthunt). We also collected information on number of doves harvested, number of shots fired, shotgun gauge, and shotshell size used. Dove carcasses were collected on both areas during 1998-99. At EBCA, 60 hunters deposited an estimated 64,775 pellets/ha of nontoxic shot on or around the managed field. At JARWA, approximately 1,086,275 pellets/ha of Pb shot were deposited by 728 hunters. Our posthunt estimates of spent-shot availability from soil sampling were 0 pellets/ha for EBCA and 6,342 pellets/ha for JARWA. Our findings suggest that existing soil sampling protocols may not provide accurate estimates of spent-shot availability in managed dove shooting fields. During 1998-99, 15 of 310 (4.8%) mourning doves collected from EBCA had ingested nontoxic shot. Of those doves, 6 (40.0%) contained ≥7 shot pellets. In comparison, only 2 of 574 (0.3%) doves collected from JARWA had ingested Pb shot. Because a greater proportion of doves ingested multiple steel pellets compared to Pb pellets, we suggest that doves feeding in fields hunted with Pb shot may succumb to acute Pb toxicosis and thus become unavailable to harvest, resulting in an underestimate of ingestion rates. Although further research is needed to test this hypothesis, our findings may partially explain why previous studies have shown few doves with ingested Pb shot despite their feeding on areas with high Pb shot availability.
A hstral't: Bone and liver lead concentrations (J..lg! gm, d.w.) were determined by atomic absorption spectrophotometry for 412 hunter-killed mourning doves (Zenaida macroura) collected from 6 Atlantic flyway game management areas located in Maryland. Virginia, North Carolina, and South Carolina, 1977 and 1978 seasons. Juvenile bone lead concentrations ranged from 1.25-763.65 J..lg! gm while adults showed levels from 1.02-322.81 J..lg! gm. Significant effects in location of collection (P<0.005) and age (P<0.005) were determined, where adults had higher bone lead concentrations than juveniles. Some juvenile birds had extremely high bone lead concentrations not found in adults. Adult liver lead concentrations ranged from 0.00-74.61 J..lg! gm and from 0.00-76.45 J..lg! gm in juveniles. In the 1978 season, liver concentrations were significantly (P<0.025) higher in the early dove season, perhaps from increased lead shot exposure. Neither bone nor liver analyses indicated a differential lead exposure pattern due to sex. Gizzard and crop examination of the 412 birds indicated II lead shot in 10 individual doves (2.4%). However, liver analyses indicated that 21 of 412 doves (5.1%) contained elevated lead concentrations that possibly resulted from lead shot exposure. For the combined years, 1977 and 1978, analyses indicated 45 of 412 (10.9%) doves to have bone lead levels> 100.00 J..lg! gm, indicating an elevated pattern of lead exposure in this species. Lead poisoning has been well documented as a significant mortality factor in eastern and central North American waterfowl populations (Bellrose, 1959, Bagley et aI., 1967). However. little is known of the extent of lead exposure in either mourning doves or upland game birds. As hunting on managed dove fields expands, more birds will become exposed to increasing amounts of spent lead shot. To indicate the exposure potential of lead shot in public dove fields. Lewis and Legler (1968) reported that the concentration of shot per hectare in the top 0.95 cm of soil in prehunt and post hunt samples was 26,898 and 107.593. respectively. The accumulation of spent lead shot on roads of managed dove field areas also is significant in that shot is likely to remain on the surface year-round. This could expose doves to shot when vegetative growth limits their use of fields. Apparently doves are ingesting these shot because investigators in Tennessee (Lewis and Legler 1968), Maryland (Locke and Bagley 1967) and Virginia (Scanlon and Mirarchi, unpublished data) have found lead shot in the gizzards of doves. In a sample (350) of Maryland doves collected on the first 4 days of the 1976 season, Scanlon and Mirarchi (unpu blished data) found that 6% of the birds had lead shot in the gizzard. Locke and Bagley (1967) reported that 6.5% of a collection of mourning doves from Maryland had lead shot in the gizzard. A confirmed case of lead poisoning in a mourning dove was reported by Locke and Bagley (1967). The bird contained 2 lead pellets in the gizzard, was moribund and emaciated, and acid-fast intranuclear inclusions were found in kidney cells. It was suggested by the authors that this could be of a more frequent occurrence in that sickened doves would be extremely difficult to locate thus allowing the problem to go undetected. Another upland game bird, the bobwhite quail (Cu!inus virKinianus), has shown similar signs of lead poisoning (Westemeier, 1966). Lead shot were detected in the gizzard and it was noted that this could be of significant consequence to upland game birds.
Sex ratios of mourning doves (Zenaida macroura) reported in banding studies have differed markedly between states and years suggesting that techniques used to assign gender may be biased. We tested this hypothesis with experienced mourning dove biologists (n = 4) who assigned age, gender, primary molt progression, and certainty of classification, using external characteristics of harvested doves (n = 468) in Missouri during September 1993. The probability of correctly classifying adult mourning doves, verified with gonadal examination, was 0.904-0.985 and 0.957-0.990 for immatures. Assessment of age and gender combined was 0.944-0.990 for adult females and 0.533-0.993 for adult males. Error probabilities of observer ability to correctly assign age and gender was 0.0-0.045 for adult females and 0.007-0.451 for adult males. Among individual mourning doves examined, only 1 adult and 6 immature doves were incorrectly assigned age and gender by all 4 participants. Error in assigning gender to adult doves could have contributed to disparate sex ratios reported in previous mourning dove banding studies. We recommend that standard training procedures be developed and implemented across states and regions in future banding studies of mourning doves.
We measured corticosterone in plasma collected from free-living AdClie Pen- guins (Pygoscelis adeliae) and made blood smears to count the ratio of heterophils to lym- phocytes (Ha). Our objective was to categorize how these two measures of stress vary with potential stressors in the birds' environment. In penguins that were repeatedly sampled from three to eight times, repeated handling did not affect corticosterone levels or HIL, but there were significant differences among individuals. Nesting stage did not affect corticosterone level, but H/L was significantly lower during the chick stage than in the courting or incu- bation stages. Sex and handling times of less than 5 min had no effect on either corticoste- rone or Ha. In birds that had fasted up to 40 days during the courtship and early incubation stages, there was no increase in corticosterone or H/L with length of fasting, but in birds that had fasted more than 50 days, corticosterone levels increased. Birds with obvious in- juries had significantly higher H/L than birds that had recently engaged in fights or those caring for chicks, but corticosterone levels did not differ in these groups. In free-living birds, HL ratios provide a measure of stress that may be more useful than a single measure of plasma corticosterone in assessing response to chronic stressors like injury or crowded conditions in the breeding colony.
Recent declines in recreational sport-hunting participation rates result from a variety of
societal and cultural changes as well as extensive changes in the distribution of the United States population. Concurrently, natural-resource agencies are undergoing broad changes in focus and goals, with holistic ecosystem management competing with traditional game management for limited financial resources. We believe that recreational hunting is an important cultural element that should remain a mainstream recreational activity and should continue to have a significant place in natural-resource agencies. Given the transition of the United States population to a more urbanized society, new innovative programs need to be developed to recruit and retain recreational sport hunters from urban population centers that provide "successful" hunting experiences. We identify several components that will be essential to the success of these programs, such as providing a reasonable expectation of success or accomplishment (e.g., harvesting an animal), providing sport-hunting opportunities near urban population centers, and providing opportunities that are sensitive to the needs of diverse groups (e.g., minority, gender). We propose 2 solutions for providing recreational hunting opportunities to residents of urban areas: 1) establishing crop fields to attract mourning doves (Zenaida macroura) and 2) implementing put-and-take hunting under certain restrictions. We recognize many possible problems with these suggested programs. Natural-resource professionals have strong opinions about
these issues, but we believe discussions are needed if hunting is to remain a mainstream recreational activity. These dialogues need to 1) address the role of recreational hunting in resource agency policies and programs, 2) identify innovative programs to educate, introduce, and retain urban residents in recreational hunting, and 3) identify innovative programs to provide urban hunters with experiences similar to those we have proposed. If we fail to recognize the emerging societal, cultural, and professional changes impacting sport-hunting participation rates, this activity likely will become an anachronism.
Effects of multiple concurrent stressors on female Hubbard × Hubbard chicks were studied in a 26-factorial experiment that employed as stressor treatments aerial ammonia (A, 0 or 125 ppm), beak trimming [B, sham handled
or beak trimmed/cauterized on trial Day 1 (posthatch Day 10)], coccidiosis (X, gavage with 0 or 6 × 105 sporulated Eimeria acervulina oocysts), intermittent electric shock (E, 0 or between 2.9 and 8.7 mA), environmental heat stress (H, air temperature 30.4
or 34.8 C), and continuous noise (N, 80 or 95 dB). Plasma corticosterone concentration on trial Day 7 was unaffected by any
stressor or stressor combination, but the heterophil:lymphocyte ratio (H/L) was increased by A, E, and H. Also, the B × X
interaction was significant for H/L. The H/L increased linearly from .53 to .86 as number of concurrent stressors increased
from zero to six. These findings indicate that the chick’s leukocyte changes in response to stress are less variable and more
enduring than its corticosterone response, and H/L are sometimes a more reliable indicator of stress.
Fecal glucocorticoid metabolite analyses are increasingly being used by a variety of scientists (e.g., conservation biologists, animal scientists) to examine glucocorticoid (i.e., stress hormone) secretion in domestic and wild vertebrates. Adrenocortical activity (i.e., stress response) is of interest to conservation biologists because stress can alter animal behavior, reduce resistance to disease, and affect population performance. The noninvasiveness of fecal-based assessments is attractive, particularly when studying endangered species, because samples can often be obtained without disturbing the animal. Despite such advantages, many confounding factors inhibit the utility of this technique in addressing conservation problems. In particular, interpretation of fecal glucocorticoid metabolite (FGM) measures may be confounded by the length of time animals are held in captivity, normal seasonal and daily rhythms, body condition, sample storage and treatment techniques, diet of the animal, assay selection, animal status (i.e., social ranking, reproductive status), sample age and condition, and sample mass. Further complicating interpretation and utility of these measures is the apparent species-specific response to these factors. The purpose of this paper is to discuss the factors that confound interpretation of FGM measures, summarize research that addresses these issues, and offer an agenda for future research and interpretation. We urge conservation biologists to carefully consider confounding factors and the relationship between FGM secretion and population performance and biological costs when investigating effects of environmental and human-induced disturbances on wildlife. The crisis nature of many decisions in conservation biology often requires decisions from limited data; however, confirmatory results should not be posited when data are incomplete or confounding factors are not understood. Building reliable databases, and research with surrogate species when possible, will aid future efforts and enhance the utility of FGM assays.
During 1987, soil samples were collected before (August) and after (October) the first dove hunting season near a stocktank in Eddy Co., New Mexico. Lead shot were recovered from 54% of 120 soil samples (30.5 by 30.5 by 1.3 cm deep) collected in August (181 shot) and from 68% of 120 soil samples collected in October (929 shot). These data provided estimates of 167,593 and 860,185 lead shot/ha in the upper 1.3 cm of soil for August and October, respectively. Examination of gizzards collected from 420 mourning doves (Zenaida macroura) during 1985, 1986, and 1987 revealed that only one had ingested lead shot. Analyses of livers of 250 doves revealed that nine (3.6%) contained concentrations of lead >7 ppm wet weight (range of 8 to 257). Though large amounts of lead were available for ingestion, doves had a low incidence of lead consumption.
Biologists in Tennessee collected 1,949 gizzards from doves harvested on fields managed for public hunting. One percent of the doves had ingested between 1 and 24 lead shot. Pre- and posthunt soil samples were collected from a field with a history of 8 years of managed public dove shooting. In the top 3/8 inch of soil there were 10,890 shot per acre before the September 1 and 2 hunt. The posthunt sample indicated 43,560 shot per acre in the top 3/8 inch.
Previous mourning dove (Zenaida macroura) telemetry studies using transmitter glue attachment have found the technique to be relatively short term (<10 weeks), and that transmitter harnesses possibly have deleterious effects on doves. To improve attachment methods, we developed and refined surgical techniques for implanting subcutaneous and intra-abdominal radiotransmitters with external whip antennas in mourning doves, and we determined physiological and pathological responses to the transmitter implants. We used a captive colony of 200 wild-trapped mourning doves to develop and test procedures for subcutaneous implants (SC1), subcutaneous surgeries without implants (SC2), intra-abdominal implants (IA1), intra-abdominal surgeries without implants (IA2), and a control group without surgeries or implants (CNT); 20 males and 20 females were assigned to each experimental group. Surgeries for IA1 took less time (3.58 +/- 0.17 min; (x) over bar +/- SE; P < 0.001) than SC1 surgeries (4.36 +/- 0.12 min). Heterophil:lymphocyte ratios showed that IA1 and IA2 doves had higher (P = 0.024) posttreatment changes compared with SC1, SC2, or CNT groups. At 4-6 days postsurgery, 153 of 160 (95.6%) doves with surgical treatments showed closed or healed surgical sites with no complications. At 14 days posttreatment, 34 (87%) SC1 implants were located in the thoracic inlet. Gross necropsy findings at 10 weeks postsurgery found that 36 of 39 (92%) SC1 and 36 of 39 (92%) IA1 implants showed little or no tissue response to the implants. Functioning transmitters began failing 2 weeks posttreatment, and 85% were not working at 10 weeks posttreatment. Our data suggest subcutaneous implants with external antennas were a better alternative compared to intra-abdominal implants with external antennas, but further testing is needed to compare subcutaneous implants to conventional attachment techniques.
Although subcutaneous radiotransmitter implants with external antennas have been shown to be a tractable transmitter attachment technique for mourning doves (Zenaida macroura), few experiments have been conducted comparing implants to conventional external attachment techniques. To determine whether implants provide an improved alternative, we compared the physiological and pathological effects of subcutaneous implants with external antennas (SC1), subcutaneous surgeries without implants (SC2), transmitters attached with harnesses (HAR), transmitters with glue attachment (GLU), and a control group (CNT) without surgery or transmitter; we also compared differences in amount of time needed to attach transmitters and transmitter retention rates. A captive colony of 195 wild-trapped doves was assigned randomly to each treatment. Average time required to attach radiotransmitters differed among treatments (P≤0.001), and was greatest for GLU (9.24 min±0.22, x̄±SE) and least for HAR (2.49±0.07). Transmitter retention rates differed among treatments (log-rank: P=0.005, Wilcoxon: P=0.016), with 100.0% of SC1 remaining attached during the 63-day post-treatment period and 38.5% of GLU. Heterophil:lymphocyte ratios (P=0.316) or body masses (P=0.305) did not differ among treatments. Pathological data showed 89.7% of HAR doves with mild to moderate thickening and yellowing of the wing skin and tissue, and 10.3% with severe thickening and yellowing skin, tissue swelling, and pressure necrosis where the harness was cutting into the wing tissue. No differences existed among treatments in 5 blood plasma chemistries (P=0.843). Our data suggest that subcutaneous implants are superior to glue attachment based on retention time, and superior to harnesses based on pathological effects. Implants do not appear to affect captive doves physiologically, though long-term effects on wild free-flying doves are unknown.
Use of ingested shotgun pellets in gizzards, concentrations of protoporphyrin (PP) in blood, and concentrations of lead in blood for detecting lead poisoning in waterfowl was evaluated in Illinois. Radiology (X ray of grit and fluoroscope of food) was significantly more reliable than manual examination in identifying gizzards with ingested pellets. Lead in blood was significantly more sensitive than either ingested pellets in gizzards or PP in blood for detecting lead poisoning. Elevated lead in blood manifests severe physiological consequences in waterfowl, including irreversible brain damage. -Authors
http://www.npwrc.usgs.gov/resource/birds/pbpoison/
Ecological and toxicological aspects of lead (Pb) in the environment are briefly reviewed, with emphasis on fish and wildlife, their predators, and prey. Subtopics include sources and uses, chemical properties, mode of action, background concentrations, lethal and sublethal effects, and current recommendations for the protection of sensitive living resources. Resources that are at increased risk from Pb include migratory waterfowl that congregate at heavily hunted staging areas and ingest shot, avian predators that consume hunter-wounded game, domestic livestock near smelters and Pb battery recycling plants, zoo animals and livestock held in enclosures coated with Pb-based paints, wildlife that forage near heavily traveled roads, and aquatic life near mining activities.
Nonparametric multiple comparisons are discussed, with particular emphasis given to stepwise procedures. Nonparametric analogs of the stepwise all-subset procedure of Einot and Gabriel are presented, along with an ad hoc nonparametric analog of the Newman—Keuls procedure. These new procedures are compared among themselves and with nonstepwise procedures based on Type I error levels and comparisonwise power. It is shown that these stepwise nonparametric procedures control Type I error levels, and that they have superior pairwise power compared to the commonly used nonstepwise procedures.
The digestive tract is not only important for nutrient digestion and absorption, but it is the largest immunological organ in the body protecting against exogenous pathogens. The digestive system has adaptations designed to facilitate flight. The length of the intestinal tract is shorter in birds relative to mammals. Also, birds lack teeth and heavy jaw muscles, which have been replaced with a lightweight bill or beak. Food particles are swallowed whole and then reduced in size by the ventriculus or gizzard located within the body cavity. This chapter will not attempt to describe the many species variations in detail but will instead describe differences between birds and mammals. The reader is referred to the excellent reviews by McLelland (1975, 1979) for specific information on various species.
There is increasing concern that birds in terrestrial ecosystems may be exposed to spent lead shot. Evidence exists that upland birds, particularly mourning doves (Zenaida macroura), ingest spent lead shot and that raptors ingest lead shot by consuming wounded game. Mortality, neurological dysfunction, immune suppression, and reproductive impairment are documented effects of exposure to lead in birds. An ecological risk assessment on the impact of lead shot exposure in upland birds was conducted and is presented in the context of the new United States Environmental Protection Agency's Ecological Risk Assessment Paradigm. A considerable amount of spent lead shot is released into the environment each year from shooting and hunting. Doves collected from fields that are cultivated to attract mourning doves for hunting activities show evidence of ingestion of spent lead shot. Because lead can cause both acute and chronic toxicity if ingested by birds, and because there is evidence of widespread deposition of lead shot in terrestrial ecosystems, concern for impacts on upland game birds and raptors seems warranted. Although this ecological risk assessment does not clearly define a significant risk of lead shot exposure to upland game birds, this issue merits continued scrutiny to protect our upland game bird and raptor resources.
In lifetesting, medical follow-up, and other fields the observation of the time of occurrence of the event of interest (called a death) may be prevented for some of the items of the sample by the previous occurrence of some other event (called a loss). Losses may be either accidental or controlled, the latter resulting from a decision to terminate certain observations. In either case it is usually assumed in this paper that the lifetime (age at death) is independent of the potential loss time; in practice this assumption deserves careful scrutiny. Despite the resulting incompleteness of the data, it is desired to estimate the proportion P(t) of items in the population whose lifetimes would exceed t (in the absence of such losses), without making any assumption about the form of the function P(t). The observation for each item of a suitable initial event, marking the beginning of its lifetime, is presupposed.
For random samples of size N the product-limit (PL) estimate can be defined as follows: List and label the N observed lifetimes (whether to death or loss) in order of increasing magnitude, so that one has Then , where r assumes those values for which and for which measures the time to death. This estimate is the distribution, unrestricted as to form, which maximizes the likelihood of the observations.
Other estimates that are discussed are the actuarial estimates (which are also products, but with the number of factors usually reduced by grouping); and reduced-sample (RS) estimates, which require that losses not be accidental, so that the limits of observation (potential loss times) are known even for those items whose deaths are observed. When no losses occur at ages less than t the estimate of P(t) in all cases reduces to the usual binomial estimate, namely, the observed proportion of survivors.
Mourning doves (Zenaida macroura) may develop Pb toxicosis from ingesting spent Pb shot from hunted fields in which they feed. One to 6.5 percent of the dove population may ingest Pb shot based on analysis of gizzard contents. No Pb shot toxicity studies have been conducted on free-ranging mourning doves. Mortality data for Pb-dosed, free-ranging doves would help determine the actual effects of Pb shot ingestion on the mourning dove population. Causes of death of Pb-treated doves also could help to estimate exposure of predators and scavengers to secondary Pb toxicosis. The objectives of this study were to compare mortality and causes of death of free-ranging Pb-treated and untreated mourning doves.
At the levels to which human beings are exposed in the workplace as well as in the general environment, lead has been shown to be a toxic element in most of its chemical forms, whether it is inhaled or ingested in water or food. The four main sources of contamination of food are soil, industrial pollution, agricultural technology and food processing. Reasonable quantities of the metal can be stored by humans in a relatively inert form in bone; lead has an affinity for bone and acts by replacing calcium. Gastrointestinal lead absorption and retention, the major pathway of lead intake, has been shown to vary widely depending on the chemical environment of the gastrointestinal lumen, age and iron stores (nutritional status of the subject). Studies in animals have shown that certain substances bind lead and increase its solubility, thus enhancing its absorption. These dietary components consist of sodium citrate, ascorbate, amino acids, vitamin D, protein and fat, and lactose. Data suggest a three-compartmental pool for lead metabolism: (1) blood; (2) soft tissue (hair, nails, sweat, salivary, gastric, pancreatic and biliary secretions); and (3) skeleton. Lead absorption occurs primarily in the duodenum where lead enters the epithelial mucosal cells. The total bodily amount of lead does not affect lead absorption; lead does not have a feedback mechanism which limits absorption. In the adult rat, lead absorption from the intestinal lumen appears to proceed by both active transport and passive diffusion. Bile is an important route of excretion in the gut.(ABSTRACT TRUNCATED AT 250 WORDS)
Ecotoxicologists and ecologists have examined the effects of pollutants on individuals and populations largely in terms of one or only a few effects. Yet the recent trend toward a holistic approach to ecological risk assessment suggests that a rigorous paradigm should be applied to toxicants, from hazard identification to risk characterization. Recent discussions have recognized that an up-front problem formulation phase is more critical in ecological risk assessment than it is for human health risk assessment. In this article a modified environmental health risk assessment paradigm is used to examine the risk of lead to birds. This risk analysis is largely conceptual, based on laboratory and field data, and incorporates information currently available. The model expands the hazard identification phase to create a target identification phase that includes the identification of receptors, endpoints, relationships, spatial and temporal scales, and indicators. The target identification phase is unique to the particular hazard, species, population, or community being examined. Lead can cause mortality, or can indirectly affect populations through effects on the food base, avian behavior, reproductive success, and recruitment. Lead can (1) decrease the abundance and availability of prey, (2) bioaccumulate in prey causing increased lead toxicosis in predators, or (3) increase prey availability by interfering with its hiding or escape behavior. Moreover, lower abundance of prey can lead to starvation or nutrient deficiencies, which amplify the absorption and retention of lead. Lead also causes decreases in clutch and egg size, mortality of embryos and nestlings, depression of growth, and deficits in behavior that affect survival. Lead decreases migratory behavior, and increases vulnerability to cold stress, hunters, and other predators. Research needs for evaluating the risk of lead in birds include obtaining data on (1) metal dynamics within various tissues as a function of dose and time since initial exposure, (2) low-level effects on embryos, (3) effects on chicks following fledging and in the period prior to recruitment, (4) effects on adult foraging skills and reproductive behavior, and (5) the relationship between effects from exposure in the laboratory and those from exposure in the wild. This latter point is extremely important, particularly if wild birds have other means of ridding the body of lead not available or less apparent to laboratory birds.
We estimated total lead shotshell pellets expended, resultant pellet availability near soil surface, and the frequency of pellet ingestion by northern bobwhites ( Colinus virginianus) attributable to nearly a quarter century of bobwhite hunting on a 202-ha upland habitat at Tall Timbers Research Station, Leon County, Florida. A total of 7776 shots were fired, resulting in the expenditure of approximately 4.5 million pellets (approximately 22519/ha). Sixteen of 235 (6.8%) soil samples collected in 1989 and 1992 contained one or two pellets. Soil samples indicated that approximately 7800 pellets/ha (about 35% of the projected 24-year deposition) were within 2.54 cm of the soil surface. Pellet ingestion by bobwhites was evaluated by examining 241 gizzards collected from 1989-92. Three bobwhites (1.3%) had ingested pellets ( x = 1.3 pellets). No instances of suspected lead poisoning were noted in bobwhites over the 24-year period. Sport hunting of wild bobwhite populations on upland habitats appears to produce a low potential for lead poisoning compared to lead deposition in association with waterfowl and dove hunting.
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Managing American wildlife: a history of the International Association of Fish and Wildlife Agencies
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Lead in the environment. National Science Foundation
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Boggess, W. R. , editor. 1977. Lead in the environment. National Science Foundation. Report NSF/RA-770214. U.S. Government Printing Office, Washington, D.C., USA.
Other toxins and poisons. Pages. 1133-1162
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Blood protoporphyrin for detecting lead exposure in canvasbacks. Pages. 32-37
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The gastrointestinal tract. Pages. 412-453
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Estimating autumn–spring waterfowl nonhunting mortality in north Missouri
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Lead poisoning of waterfowl and raptors. Pages. 108-117 Noninfectious diseases of wildlife
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Manual of ornithology: avian structure and function
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Appendix 13: a synopsis of the nontoxic shot issue. Pages. 317-319 Final supplemental environmental impact statement: issuance of annual regulations permitting the sport hunting of migratory birds (SEIS 88)
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U.S. Fish and Wildlife Service. 1988. Appendix 13: a synopsis of the nontoxic shot issue. Pages. 317-319. In. Final supplemental environmental impact statement: issuance of annual regulations permitting the sport hunting of migratory birds (SEIS 88). U.S. Government Printing Office, Washington, D.C., USA.
Lead poisoning of waterfowl and raptors. Pages 108–117 in A Multiple concurrent stressors in chicks. 3. Effects on plasma corticosterone and the heterophil:lymphocyte ratio
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Locke, L. N., and N. J. Thomas. 1996. Lead poisoning of waterfowl and raptors. Pages 108–117 in A. Fairbrother, L. N. Locke, and G. L. Hoff, editors. Noninfectious diseases of wildlife. Second edition. Iowa State University Press, Ames, USA. McFarlane, J. M., and S. E. Curtis. 1989. Multiple concurrent stressors in chicks. 3. Effects on plasma corticosterone and the heterophil:lymphocyte ratio. Poultry Science 68:522–527.
Appendix 13: a synopsis of the nontoxic shot issue. Pages 317–319 in Final supplemental environmental impact statement: issuance of annual regulations permitting the sport hunting of migratory birds (SEIS 88) Stress, corticosterone, and heterophil to lymphocyte ratios in free-living Adelie penguins
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- T L Bucher
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Gastrointestinal anatomy and physiology Sturkie's avain physiology. Fifth edition
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