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Osprey Population Increase along the Willamette River, Oregon, and the Role of Utility Structures, 1976–93

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... Recently, Henny and Kaiser (1996) studied an expanding Osprey population in the Willamette Valley of Oregon, quite similar to the Clear Lake population in that it was recently increasing from previous (organochlorine) pollution-related decimations (Poole et al. 2002), expanding into new habitat, and apparently not yet proximally limited by either nest site availability or food levels. From 1976 to 1993, Henny and Kaiser (1996) documented an increase from 13 to 78 active pairs. ...
... Recently, Henny and Kaiser (1996) studied an expanding Osprey population in the Willamette Valley of Oregon, quite similar to the Clear Lake population in that it was recently increasing from previous (organochlorine) pollution-related decimations (Poole et al. 2002), expanding into new habitat, and apparently not yet proximally limited by either nest site availability or food levels. From 1976 to 1993, Henny and Kaiser (1996) documented an increase from 13 to 78 active pairs. In 1993, the Oregon population produced an average of 1.64 YY/NA, although the nesting population had undergone an exponential rate of increase since 1976, very similar to the population expansion of a smaller size at Clear Lake. ...
... But even more importantly, it has been established in modern resource management that Osprey populations respond strongly and effectively to the availability of adequate, stable nest sites and abundant food (Poole 1989a, b, Henny andKaiser 1996); and grebe populations respond best if protected from disturbances and other man-induced perturbations (see Anonymous 1999). At Clear Lake, there was a continuing positive relationship between nesting Ospreys and the local power company. ...
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Mercury (Hg) and reproduction and status of Western and Clark’s Grebes (Aechmophorus sp.) and Osprey (Pandion haliaetus) were studied from 1992 through 2001 and then less intensely through 2006 at Clear Lake, California, USA. Remediation to reduce Hg loading from the Sulphur Bank Mercury Mine was initiated in 1992. Mercury in grebe feathers declined monotonically from ;23 mg/kg dry mass (DM) in 1967–1969 to 1 mg/kg in 2003, but then increased to 7 mg/kg in 2004–2006. Mercury in Osprey feathers varied similarly, with mean values of 20 mg/kg DM in 1992, declining to a low of 2 mg/kg in 1998, but increasing to 23 mg/kg in 2003, and 12 mg/kg in 2006. Mercury in Osprey feathers at our reference site (Eagle Lake, California) remained low (1–8 ppm) throughout the entire period, 1992–2003. Grebe productivity at Clear Lake improved from ;0.1 to 0.5 fledged young per adult during the latter part of the study when human disturbance was prevented. At that period in time, improved productivity did not differ from our reference site at Eagle Lake. Human disturbance, however, as a co-factor made it impossible to evaluate statistically subtle Hg effects on grebe productivity at Clear Lake. Osprey reproduced sufficiently to maintain increasing breeding numbers from 1992 to 2006. Mercury in Clear Lake water, sediments, invertebrates, and fish did not decline from 1992 to 2003, but a shift in trophic structure induced by an introduced planktivorous fish species may have caused significant alterations in Hg concentrations in several species of prey fishes that may have produced concomitant changes in Osprey and grebe Hg exposure. The temporary declines observed in grebe and Osprey feather residues in the late 1990s, with coincidental improvements in reproductive performance, however, could not be attributed to remediation at the mine site.
... Historically, Gabrielson and Jewett (1940:199) reported Osprey as 'formerly common along the Columbia and Willamette Rivers... must now be considered one of the rarer Oregon hawks'. More recently, this population of nesting Ospreys increased from an estimated 13 pairs in 1976 to 78 pairs in 1993 (Henny and Kaiser, 1996). Therefore, the Osprey population in 1993 was increasing at a rapid rate when 10 eggs and 25 composite samples of fish (Largescale Sucker (Catostomus macrocheilus), Mountain Whitefish (Prosopium williamsoni) and Northern Pikeminnow (Ptychocheilus oregonensis)) were collected for contaminant evaluation. ...
... Of the three species of fish collected by electrofishing during this study, Largescale Suckers were generally the largest (means of composites, 537 to 967 g), with Northern Pikeminnows (means 168 to 310 g) and Mountain Whitefish (means 205 to 277 g) similar in size (Table I). Mountain Whitefish were not found in the Willamette River below RM 146, and Largescale Sucker and Northern Pikeminnow collections were not made below RM 54 as few Ospreys nested there in 1993 (Henny and Kaiser, 1996). ...
... Before evaluating effects of contaminants on Osprey productivity two points need to be emphasized: (1) the Osprey population nesting along the Willamette River increased in recent years at a rapid rate (from 13 pairs in 1976 to 78 pairs in 1993) (Henny and Kaiser, 1996), and (2) the observed production rate in 1993 (1.64 young/active nest) was about twice the estimated rate required to maintain a stable population (0.80 young/active nest) in the northeastern United States (Spitzer, 1980;Spitzer et al., 1983). More recent information mentioned above showed that the population continued to increase (234 nesting pairs in 2001), thus, a priori contaminant effects were minimal. ...
... Only one BMF estimate was made for each contaminant, and it only represented samples (eggs and fish) collected from the Upper River. The osprey population nesting on the main stem Willamette River and lower Santiam River (hereafter, Santiam River) increased from 13 pairs in 1976 to 78 pairs in 1993 (Henny and Kaiser 1996) to 234 pairs in 2001 (Henny et al. 2002a), including an expansion of the local breeding range downstream into the heavily industrialized harbor area of Portland. In 2001, we collected and analyzed additional osprey eggs and prey fish species from the Santiam River and further downstream in Newberg Pool and Tidal Portland (Fig. 1). ...
... In Tidal Portland, below Willamette Falls (a drop of about 14 m), the river enters industrial Portland Harbor with tidal influences and the greatest average depth and channel width (Tetra Tech 1992). Background information on migratory ospreys that nest along the Willamette River was provided in earlier reports (Henny and Kaiser 1996; Martell et al. 2001; Henny et al. 2002a Henny et al. , 2003). This breeding population primarily builds its nests on power poles located in agriculture fields along the Upper Willamette and Lower Santiam Rivers while primarily selecting various other artificial structures (e.g., cellular towers, river pilings) for nest sites in urban areas further downstream. ...
... In 1993, a single osprey egg was collected at 10 nests on the Upper River from a breeding population of 56 pairs and represented the complete length of the reach (Henny and Kaiser 1996; Henny et al. 2003). No eggs were collected from the 20 nests on the Santiam River or further downstream on the Willamette River because only two pairs were nesting there. ...
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The osprey (Pandion haliaetus) population nesting along the main stem Willamette River and lower Santiam River was first studied to evaluate contaminants and reproductive rates in 1993 when 78 occupied nests were present. By 2001, the population increased to 234 occupied nests, a 13.7% annual rate of population increase. A sample egg was collected from each of a series of nests along the Upper River (river mile 55-187) in 1993, 2001 and 2006 to evaluate trends of persistent contaminants (organochlorine [OC] pesticides, polychlorinated biphenyls [PCBs], polychlorinated dibenzo-p-dioxins [PCDDs], and polychlorinated dibenzofurans [PCDFs]). Nearly all OC pesticide residues decreased significantly, e.g., p, p'-DDE (DDE) from 2,350 to 1,353 to 210 microg/kg wet weight (ww). PCBs followed a similar pattern over time, e.g., SigmaPCBs 688 to 245 to 182 microg/kg ww, while PCDDs and PCDFs showed a more precipitous decline (often 85-95%) between 1993 and 2001, with no egg analyses warranted in 2006. During 2001-2002, sample osprey eggs were also collected from nests at three Headwater Reservoirs and two lower reaches (Newberg Pool and Tidal Portland) of the Willamette River, as well as the lower portion of the Santiam River to evaluate spatial residue patterns. Significant differences were seldom detected among the different sampling areas for OC pesticides (probably due to small sample sizes), although higher concentrations were often seen in the lower reaches, e.g., DDE 901 microg/kg ww (Headwater Reservoirs), 1,353 (Upper River), 1,384 (Newberg Pool) and 2,676 (Tidal Portland). PCB congener concentrations in eggs were usually higher in the Tidal Portland reach than at other locations and often significantly higher than at the Headwater Reservoirs or Upper River. Mercury (first analyzed in eggs in 2001), PCDDs and PCDFs were extremely low in 2001/2002 with no significant spatial patterns. Whole fish composite samples of largescale sucker (Catastomus macrocheilus) and northern pikeminnow (Ptychocheilus oregonensis), which account for about 90% of the biomass in the diet of this osprey population, were also collected from the Willamette River in 1993 and 2001 and analyzed for the same contaminants as osprey eggs. Contaminant residues in fish from the Upper River decreased between 1993 and 2001, paralleling findings for osprey eggs. Likewise, spatial patterns for fish residues paralleled findings for osprey eggs from the different reaches in 2001. A second empirical estimate of biomagnification factors (BMFs) from fish to osprey eggs for OC pesticides, PCBs, PCDDs and PCDFs (ww and lipid weight [lw] basis) was calculated based on residue data collected in 2001. The two independent BMF estimates (1993 and 2001) for each contaminant from the Upper River provide a measure of consistency, e.g., DDE (ww) 87 and 79, (lw) 103 and 112; SigmaPCBs (ww) 11 and 8.4, (lw) 13 and 12. Mercury did not biomagnify from fish to osprey eggs (BMF = 0.60). Legacy contaminants investigated had limited (perhaps only DDE), if any, effects on reproductive success of the increasing osprey population nesting along the Willamette River by 2001.
... This suggests that Ospreys continue to rebound from the deleterious effects of the DDT era ( Speitzer et al. 1978). Increasing availability of reservoirs and artificial nesting platforms also has contributed to higher nesting densities and breeding-range expansion (Swenson 1981, Henny 1983, Henny and Kaiser 1995. ...
... This suggests that Ospreys continue to rebound from the deleterious effects of the DDT era ( Speitzer et al. 1978). Increasing availability of reservoirs and artificial nesting platforms also has contributed to higher nesting densities and breeding-range expansion (Swenson 1981, Henny 1983, Henny and Kaiser 1995. ...
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Trained observers counted migrating raptors and vultures from ridgetops at six sites in the Intermountain and Rocky Mountain Flyways of western North America: Goshute Mountains, Nevada (autumn 1983–2001); Wellsville Mountains, Utah (autumn 1977–1979 and 1987–2001); Bridger Mountains, Montana (autumn 1992–2001); Manzano Mountains, New Mexico (autumn 1985–2001); Sandia Mountains, New Mexico (spring 1985–2001); and Lipan Point, Arizona (autumn 1991–2001). We analyzed site-specific trends in annual passage rates (raptors per 100 hr of observation), conducting species-level analyses for 13 species and age-specific analyses for Northern Goshawks (Accipiter gentilis) and Golden Eagles (Aquila chrysaetos). Our findings suggest that, until the late 1990s when possibly drought-related downturns began, Intermountain–Rocky Mountain populations of Turkey Vultures (Cathartes aura), Ospreys (Pandion haliaetus), Broad-winged Hawks (Buteo platypterus), Red-tailed Hawks (B. jamaicensis), Merlins (Falco columbarius), and Peregrine Falcons (F. peregrinus) were increasing for diverse reasons. In contrast, our migration data and other sources indicate concern over the status of western Golden Eagles and Ferruginous Hawks (B. regalis), and uncertainty about the status of western Northern Goshawks and American Kestrels (F. sparverius). Breeding Bird Survey and Christmas Bird Count trends generally corroborated our results. The migration data reveal regional variation in the status of some species, give new insight concerning Golden Eagle and Northern Goshawk migrations, and suggest effects of an ongoing, widespread drought. Our analyses demonstrate the value of standardized, long-term migration counts for monitoring the regional status and trends of migratory raptors in western North America. Tendencias Poblacionales de Aves Rapaces Migratorias en el Oeste de Norte América Entre 1977 y 2001 Resumen. Varios observadores entrenados contaron aves rapaces migratorias desde las cimas de montañas en seis sitios en los corredores de vuelo inter-montañas y de las Montañas Rocallosas en el oeste de Norte América: Goshute Mountains, Nevada (otoño 1983–2001); Wellsville Mountains, Utah (otoño 1977–1979 y 1987–2001); Bridger Mountains, Montana (otoño 1992–2001); Manzano Mountains, New Mexico (otoño 1985–2001); Sandia Mountains, New Mexico (primavera 1985–2001); Lipan Point, Arizona (otoño 1991–2001). Analizamos las tendencias específicas de cada sitio en las tasas anuales de paso (número de rapaces por 100 hr de observación), realizando análisis por especie para 13 especies y por edad para las especies Accipiter gentilis y Aquila chrysaetos. Nuestros hallazgos sugieren que hasta finales de los años 1990s (cuando comenzaron a verse tendencias negativas posiblemente relacionadas con sequías) las poblaciones de Cathartes aura, Pandion haliaetus, Buteo platypterus, B. jamaicensis, Falco columbarius y F. peregrinus estaban aumentando por diversos motivos. En contraste, nuestros datos de migración y otras fuentes causan preocupación en cuanto al estatus de A. chrysaetos y B. regalis, e incertidumbre sobre el estatus de A. gentilis y F. sparverius. Las tendencias evidentes en los censos de aves reproductivas y los conteos navideños generalmente corroboraron nuestros resultados. Los datos de migración mostraron la existencia de variación regional en el estatus de algunas especies, revelaron información nueva con respecto a las migraciones de A. chrysaetos y A. gentilis e indicaron los efectos de una sequía actual generalizada. Nuestros análisis demuestran el valor de conteos estandarizados de aves rapaces migratorias a largo plazo para monitorear el estatus regional y las tendencias poblacionales de estas aves en el oeste de Norte América.
... It has been suggested that the collection of a sample egg may bias productivity rates. For some datasets, a difference has been noted in productivity between sampled and unsampled nests, and some investigators (Henny and Kaiser, 1996) adjust productivity to account for sample egg collection. However, in other studies no differences in productivity between sampled and unsampled nests have been noted (Rattner et al., 2004;Toschik et al., 2005). ...
... Nests at the Poplar Island reference site from which a sample egg was collected fledged 1.38 young, while unsampled nests from this site fledged 1.31 young. Unlike Henny and Kaiser (1996), Henny et al., 2004, the present study limited sampling to nests containing three or more eggs, which may account for this difference. ...
... Osprey (Pandion haliaetus (L., 1758)) populations worldwide have increased after recovering from exposure to environmental contaminants during the 1940s to the 1970s. Recovering populations have exploited habitat created dur-ing reservoir construction and the placement of utility poles and other artificial nest structures (Henny and Kaiser 1996;Ewins 1997). These increasing populations of ospreys have provided another opportunity to examine settlement patterns and selection over long temporal and large spatial scales. ...
... Diet varied among the reaches and differences in prey availability and abundance, neither of which were quantified, were hypothesized to account for osprey distribution and reproduction. None of the subpopulations were limited by the availability of nest sites (Grover 1983), a common characteristic of the species because of its willingness to nest on utility poles and artificial nest structures (Poole 1989;Ewins 1996;Henny and Kaiser 1996). ...
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In 1998 and 1999, we determined the spatial distribution, foraging behavior, and reproductive success of ospreys (Pandion haliaetus (L., 1758)) nesting along the upper Missouri River, Montana. We combined our data with that collected in the same area in 19811982 and 19901991 to investigate factors influencing settlement patterns. The study area was composed of four distinct habitats, three reservoirs and one free-flowing river section. Although number of occupied nests on each habitat increased from 19811982 to 19981999, the greatest percentage increases in nest density occurred on habitats previously hypothesized to contain the least prey. Osprey reproductive success was positively related to foraging rates, which differed across habitats, being highest on reservoirs and lowest on the free-flowing river. However, reproductive success was adequate for replacement on each habitat. Most fish consumed by ospreys on each habitat were suckers (Catostomidae), followed by salmonids and cyprinids. Fish density, determined from gill netting, was highest on the largest and shallowest reservoir. Over two decades, ospreys shifted their relative spatial use of the upper Missouri River such that reservoirs were occupied first and the free-flowing river section was occupied last. The degree to which presence of conspecifics, distribution of nest trees and prey, and dispersal affected settlement patterns probably varied by spatial scale.
... Wisconsin Stout et al. (1996) Billboard (3) Osprey Utility towers Use of utility structures has increased with population growth along the Willamette River (OR) while use of natural structures has remained constant, 1976-1993 production equal Oregon Henny and Kaiser (1996) High use of towers in Canada and eastern US ...
... Success: artificial sites > natural sites Germany Meyburg et al. (1996) Miscellaneous Absence of suitable nest trees has lead to >75% use of man-made structures (power lines) Germany Meyburg et al. (1996) Success: man-made nest structure (n = 366) > natural structure (n = 258) Utility poles Utility pole nest success = natural site success Oregon Henny and Kaiser (1996) Ferruginous Hawk Artificial structures Nest success: artificial > natural Wyoming Tigner et al. (1996) Bell et al. (1996) American Kestrels Nest boxes Use in agricultural areas Idaho Bechard and Bechard (1996) High use along highways Iowa Varland and Loughin (1993) eagle, bald eagle, American kestrel, Swainson's hawk, eastern screech owl, Harris' hawk, prairie falcon and zone-tailed hawk use power line structures in the US. Some species are more flexible in their use of structures than others ( Table 2). ...
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The effect of urbanization can be immense, yet our understanding is rudimentary. Here, we compile the most recent information on urban impacts on avian populations and communities. Compared to other vertebrates, birds are easily monitored by skilled observers and provide a mechanism to explore urban effects and responses to different urban designs. Taxonomically, bird communities in distinctly different habitats are most different in the least disturbed sites and the most similar in the most urbanized sites. Urbanization tends to select for omnivorous, granivorous, and cavity nesting species. Increased urbanization typically leads to an increase in avian biomass but a reduction in richness. Unlike most passerines, raptors may have home ranges that extend beyond the urban boundary and therefore do not need to meet all their ecological requirements within urban areas. Urban habitats are often of superior quality to raptors because there they are often free from persecution and have an adequate food supply. The processes that underlie the patterns of population and community level responses need more attention, but several areas of have been identified as being important. Birds respond to vegetation composition and structure, and urban areas that retain native vegetative characteristics retain more native species than those that do not. Avian fecundity in urban areas is a reflection of species-specific adaptability to urban resources, and to levels of nest predation and nest parasitism. Additionally, non-consumptive human activities that increase with urbanization are recognized as having negative impacts on avian populations and communities. Avian survivorship in urban areas is influenced by risk of collision with man-made objects, changes in the predator assemblage, food supply, and disease. Missing are thorough investigations in the regions of highest human population growth, e.g. Southeast Asia. Additionally, there is a paucity of information from regions of high avian diversity, e.g. tropical forests. Clearly, local knowledge and study is required before implementation of management policies to reduce urban impacts on bird communities. Hopefully, such policies will include long-term monitoring. Demographic parameters of fecundity and survivorship need to be examined in conjunction with measures of community diversity and density across the urban gradient to better understand the quality of different urban habitats, and the variation of quality among spatial patterns of urbanization within the native habitat matrix.
... Following the ban of DDT use in the United States in 1972, osprey have recovered remarkably, and abundance may now exceed historic levels. The number of breeding osprey, which has been estimated since 1990, reflects a possible increase of ≥50-100% in many areas in recent years (Henry and Kaiser 1996). These changes also likely reflect increased availability of nest platforms and other artificial nesting sites, the osprey's ability to habituate to human activity, and the species' broad piscivorous diet (Poole et al. 2002). ...
Technical Report
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Osprey (Pandion haliaetus), bald eagle (Haliaeetus leucocephalus), and peregrine falcon (Falco peregrinus) are ecologically important bird species that suffered dramatic population declines during the 1950s through 1970s. Those declines were fueled by accumulating high levels of environmental contaminants, such as lead and pesticides. Such contaminants can have adverse impacts on raptors, including thinning of eggshells that leads to poor reproductive success. Reproductive performance of these species has been used as an indicator of the health of populations. Since the banning of the pesticide dichlorodiphenyltrichloroethane (DDT) in 1974, populations have slowly rebounded. Information relating to their recovery and current status has prompted continued monitoring of these species in many states across the United States, and within North Cascades National Park Service Complex, Washington. Study areas for this report included the Ross Lake and Lake Chelan National Recreation Areas of the park complex. We conducted surveys for nesting osprey, peregrine falcon, and bald eagle from 1979–2020, 2006–2020, and 2015–2020, respectively. We assessed reproductive output by annually conducting an early nesting survey in mid-April to determine nest occupancy, followed by at least two surveys during late season nesting in early to late July to determine reproductive output. Additional surveys were sometimes necessary during the late nesting period to accurately assess nest occupancy and productivity, depending on individual nesting circumstances. Successful nesting rates were measured by the number of successful nests per occupied nests during the early nesting period. Productivity was measured by the number of young seen on the nest, regardless of age. We surveyed 1–13 osprey nesting territories annually, and found an occupancy rate of 73%, which is consistent with other populations that are stable; however, the successful nesting rate was only 33%, which is 10–35% lower than success rates reported for other populations. Successful nests averaged 1.4 young per year, which is within the normal range of mean productivity rates reported in western North America (1.3–1.8 young/nest). The percentage of osprey nest sites occupied, and nesting success, both appeared to increase gradually from 1979–2020. We surveyed 3–7 peregrine falcon nesting territories annually, and found an occupancy rate of 72.5%, which is slightly less than 79–82% occupancy reported elsewhere in Washington. The successful nesting rate for peregrine falcons in the park complex was 51%, and other recovering populations ranged 62–83%. Productivity averaged 1.3 young per nest, which is within the range suggested for a sustainable population with potential for growth (1.25–1.5 young fledged per pair). Since 2009, the number of occupied peregrine falcon territories, successful nests, and productivity of peregrine falcons in the park complex exhibited a notable decline. We surveyed 3–4 bald eagle nesting territories annually, and found an occupancy rate of 47%. This is notably less than a statewide survey in 2005 that reported an occupancy average of 75%. The successful nesting rate in the park complex was 50%, and a minimum level of 45% nest success has been suggested as the threshold for populations to remain stable. Bald eagle nest productivity in the park complex averaged 0.95 young per occupied nest, which is less than the average 1.2 young per nest reported for the rest of the United States. Although the time series is short, the percent of occupied nests and nest success both declined from 2015–2020. The nesting success of all three raptor species was variable from year to year within the study area, which is normal for raptors. Nesting parameters were on the lower end of suggested values for sustainable populations, yet likely represent stable populations. Factors that may affect the reproductive variability observed vary from observation bias to on-going threats arising from anthropogenic disturbance, environmental contaminants, and climate change. Empirical analytical results from liver biopsies of collected bald eagle and peregrine falcon mortalities in the park complex include detections of lead, mercury, and other heavy metals, as well as one polychlorinated biphenyl (PCB). No microplastics were found in gastrointestinal tracts of any of those individuals. Osprey, peregrine falcons, and bald eagles appear to be important sentinels of aquatic ecosystem health and warrant further monitoring. Management implications include the need for more holistic monitoring of ecosystem health that includes consistent community measures across trophic levels (e.g. raptors, fish, aquatic invertebrates), and environmental contaminants in particular, as well as continued assessment of visitor use management and the nexus of climate change with those factors.
... Many areas rich in food resources but lacking nest sites can support raptor breeding populations once nest sites become available, either by natural causes or by the artificial placement of anthropogenic structures (Newton 1979, Tapia andZuberogoitia 2018). In several cases, intentional placement of anthropogenic structures has contributed to increased rates of nesting attempts and a resultant increase in raptor populations (Bortolotti 1994, Cade et al. 1996, Henny and Kaiser 1996, Stout et al. 1996. In other cases, a broad range of human-made structures not intentionally placed for this purpose, such as buildings, bridges, overpasses, light towers, communication antennas, utility structures, and petroleum/gas extraction machinery have been successfully used as nesting sites by raptors (Ellis et al. 2009, Dwyer and Della Rosa 2015, Dykstra 2018, Saggese et al. 2021. ...
... However, although secondary toxicity of rotenone to fisheating birds or mammals is of limited concern, effects of reduced food supplies on local fish-eating bird populations following fish removal started to receive attention by the 1970s (Koplin 1971). Ospreys (Pandion haliaetus) nesting near inland lakes or reservoirs require waters with abundant mediumsized (150-350 mm) fish species vulnerable to capture near the surface (Lind 1976, Swenson 1978, Van Daele and Van Daele 1982, Hagan and Walters 1990, and generally located within 1.6 km of nest sites, but sometimes 3-10 km away (Garber 1972, Airola and Shubert 1981, Henny and Kaiser 1996, Ewins 1997. Clearly, Ospreys seek to minimize energy expenditure whenever possible and nest close to fish resources, but have some flexibility, though perhaps at a cost to their reproductive success. ...
Article
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Fisheries managers used the fish toxicant rotenone to eradicate an undesirable brown bullhead (Ameiurus nebulosus) population and all other fish species at Hyatt Reservoir, Oregon, on 12 October 1989. This 4-yr study (1988–1990, 1992) compared effects of that rotenone project on Ospreys (Pandion haliaetus) nesting at Hyatt Reservoir and nearby Howard Prairie Reservoir (untreated reference)—the latter a reservoir where both brown bullheads and hatchery-released rainbow trout (Oncorhynchus mykiss) prospered. Because Hyatt Reservoir was treated after Osprey fall migration in 1989, the first 2 yr (1988 and 1989) yielded pretreatment information: number of Osprey pairs was unchanged and reproductive rates were similar and consistent at the two reservoirs. Yearling fish (200–250 mm) were restocked at Hyatt Reservoir in the spring of 1990 and Ospreys returned each year following rotenone treatment, with no decline in the number of occupied or active nests. The negative effect of the rotenone treatment on Ospreys was short-term, resulting in reduced reproductive rates (young/occupied nest, young/active nest, and young/successful nest) during the first nesting season posttreatment, although hatching rates were not affected. Osprey dive success and prey delivery rates declined sharply in 1990, leading to competition for food among siblings and brood reduction. Osprey reproductive rates and prey delivery rates at Hyatt Reservoir in both 1990 and 1992 remained below the extremely high pretreatment rates, but within the range required for population stability. Serious adverse effects of the fish loss on Osprey reproduction were minimized by: (1) the delay of the rotenone application until after breeding season, (2) the restocking of the treated reservoir in the following spring with some larger (yearling) fish (though the timing was late), (3) the maintenance of a supplemental feeding program for a nesting pair of Bald Eagles (Haliaeetus leucocephalus), which minimized kleptoparasitism on Ospreys, and perhaps most important (4) the presence of nearby water bodies, where Osprey obtained some fish in the 1990 and 1992 breeding seasons.
... Western U.S. Ospreys came from the lower Columbia River (river miles 76-286) bordering Oregon and Washington, and the Willamette Valley in western Oregon. Here the migration study was integrated into ongoing population and contaminant research (Henny and Kaiser 1996). CAPTURE Adult birds were trapped on their nesting territories using either a noose carpet placed over the nest, or a modified dho-ghaza, using mist nets with a Great Horned Owl (Bubo virginianus) as a lure (Bloom 1987). ...
Article
Satellite telemetry was used to determine fall migratory movements of Ospreys (Pandion haliaetus) breeding in the United States. Study areas were established along the lower Columbia River between Oregon and Washington; in north-central Minnesota; on Shelter Island, New York; and in southern New Jersey. Seventy-four adults (25 males, 49 females) were tracked from 1995 through 1999. Migration routes differed among populations but not by sex. Western Ospreys migrated through California and to a lesser degree other western states and wintered in Mexico (88%), El Salvador (6%), and Honduras (6%) (25.9°N to 13.0°N and 108.3°W to 87.3°W). Minnesota Ospreys migrated along three routes: (1) through the Central U.S. and then along the east coast of Mexico, (2) along the Mississippi River Valley, then across the Gulf of Mexico, or (3) through the southeastern U.S., then across the Caribbean. East Coast birds migrated along the eastern seaboard of the U.S., through Florida, and across the Caribbean. Midwestern birds wintered from Mexico south to Bolivia (22.35°N to 13.64°S, and 91.75°W to 61.76°W), while East Coast birds wintered from Florida to as far south as Brazil (27.48°N to 18.5°S and 80.4°W to 57.29°W). Dates of departure from breeding areas differed significantly between sexes and geographic regions, with females leaving earlier than males. Western birds traveled a shorter distance than either midwestern or eastern Ospreys. Females traveled farther than males from the same population, which resulted in females typically wintering south of males. Rutas de Migración Otoñales, Coordinación y Sitios de Invernada de Pandion haliaetus Determinados por Telemetría Satelital Resumen. Se utilizó telemetría satelital para determinar los movimientos de migración de otoño de individuos de Pandion haliaetus que nidifican en los Estados Unidos. Las áreas de estudio se establecieron a lo largo del Río Columbia entre Oregon y Washington; en el centro-norte de Minnesota; en la Isla Shelter, Nueva York; y en el sur de Nueva Jersey. Setenta y cuatro adultos (25 machos, 49 hembras) fueron seguidos mediante telemetría desde 1995 hasta 1999. Las rutas de migración se diferenciaron entre poblaciones pero no entre sexos. Los individuos de P. haliaetus del oeste, migraron a través de California y en menor grado a través de otros estados del oeste e invernaron en México (88%), El Salvador (6%) y Honduras (6%) (25.9°N a 13.0°N y 108.3°O a 87.3°O). Las aves de Minnesota migraron a lo largo de tres rutas: (1) a través del los E.E.U.U. centrales y luego a lo largo de la costa este de México, (2) a lo largo del valle del Río Mississippi y luego a través del Golfo de México, o (3) a través del sur de los E.E.U.U. y luego a través del Caribe. Las aves de la costa este, migraron a lo largo de la costa este de los E.E.U.U., por Florida y a través del Caribe. Las aves del medio-oeste, invernaron desde México hacia el sur hasta Bolivia (22.35°N a 13.64°S, y 91.75°O a 61.76°O), mientras que las aves de la costa este invernaron desde Florida hasta tan al sur como Brasil (27.48°N a 18.5°S y 80.4°O a 57.29°O). Las fechas de partida desde las áreas de nidificación difirieron significativamente entre sexos y regiones geográficas, partiendo las hembras antes que los machos. Las aves del oeste viajaron distancias más cortas que las aves del medio-oeste y del este. Considerando una misma población, las hembras viajaron más lejos que los machos, lo que resultó en que las hembras invernaron típicamente más al sur que los machos.
... Гнездование скоп на опорах ЛЭП является распространенным явлением в США и странах зарубежной Европы (Cramp, Simmons, 1980;Hemke, 1983;Ruhle, 1985;Palmer, 1988;Poole, 1989;Meyburg et al., 1995;Henny, Kaiser, 1996;Ewins, 1996;1997;Mebs, Schmidt, 2014), однако в России такие случаи единичны и известны лишь в бассейне Волги (Бакка и др., 2008; Динкевич, 2011; Карякин, 2016), а в Саянах до последнего времени вовсе не регистрировались. ...
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There was an inhabited Osprey nest found on 22th of June, 2016 on the route along Bolshoy On river at 1321 m above sea level altitude. This nest was built on horizontal beam of metallic pillar of high-voltage powerline near Abaza – Akdovurak highway. At the moment of the discovery the female was in the nest (possibly warming the young nestlings), the male was sitting nearby. Taking into account the narrow width and shallow depth of Bolshoy On river in this place, one can assume that the feeding place for the pair is the Marankul lake situated 4.5 km away from the discovered nest.
... This availability of high densities of prey may increase both functional and numerical responses of raptors (Solomon 1949, Boal and Mannan 1998, Curtis et al. 2006, Stout 2009). Urban landscapes also may provide unique and abundant nesting structure and habitat for a variety of raptor species (Henny and Kaiser 1996, Cade et al. 1996, Meyburg et al. 1996, Marti et al. 2005, including many woodland raptors in North America (Trexel et al. 1999, Dykstra et al. 2000, Coleman et al. 2002. ...
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... A summary of estimated osprey pairs nesting in each state was prepared FL, MD, NJ, NY, OH, SC 196426 26 Wiemeyer et al., 1980CT, MA, NJ, NY, WI 196925 Spitzer et al., 1977CT, NY 196968 Spitzer et al., 1978NJ 1970-197414 Wiemeyer et al., 1978FL 19723 Szaro 1978ID 197211 Johnson et al., 1975WY 19724 Swenson 1979MA, MD, VA 1973-198725 Audet et al., 1992FL 1974-19752 4 Sundlof et al., 1986IA, MA, MD, NC, NJ SC, VA, WI 197522 Wiemeyer et al., 1987CA 1977-198415 Littrell 1986MI 1980-198925 Ewins et al., 1999ID, OR, WA 1981-198612 Henny and Anthony 1989NJ 198917 Clark et al., 200113 Henny et al., 2003NC 199512 Augspurger et al., 1996WI 199235 Karasov & Meyer 2000WI 199235 Woodford et al., 1998OR, WA 19956 Elliott et al., 1998OR, WA 19916 Elliott et al., 2000OR, WA 199514 Elliott et al., 2001bOR, WA 1997 for 1981 (Henny, 1983) and again for 1994 (Houghton & Ryman, 1997). More recent surveys showed dramatic increases in nesting numbers of ospreys for both North America and Europe (Henny et al., 1991(Henny et al., , 2008cHenny & Kaiser, 1996;Meyberg et al., 1996;Ewins, 1997;Saurola, 1997;Henny & Anderson, 2004;Watts et al., 2004;Nygård et al., 2006;Saurola, 2005;Zachos & Schmölcke, 2006). Increases in nesting numbers now appear to be limited only by nest site availability, food resources, and perhaps exposure to contaminants in heavily polluted areas. ...
... Western U.S. Ospreys came from the lower Columbia River (river miles 76-286) bordering Oregon and Washington, and the Willamette Valley in western Oregon. Here the migration study was integrated into ongoing population and contaminant research (Henny and Kaiser 1996). CAPTURE Adult birds were trapped on their nesting territories using either a noose carpet placed over the nest, or a modified dho-ghaza, using mist nets with a Great Horned Owl (Bubo virginianus) as a lure (Bloom 1987). ...
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Satellite telemetry was used to determine fall migratory movements of Ospreys (Pandion haliaetus) breeding in the United States. Study areas were established along the lower Columbia River between Oregon and Washington; in north-central Minnesota; on Shelter Island, New York; and in southern New Jersey. Seventy-four adults (25 males, 49 females) were tracked from 1995 through 1999. Migration routes differed among populations but not by sex. Western Ospreys migrated through California and to a lesser degree other western states and wintered in Mexico (88%), El Salvador (6%), and Honduras (6%) (25.9 degreesN to 13.0 degreesN and 108.3 degreesW to 87.3 degreesW). Minnesota Ospreys migrated along three routes: (1) through the Central U.S. and then along the east coast of Mexico, (2) along the Mississippi River Valley, then across the Gulf of Mexico, or (3) through the southeastern U.S., then across the Caribbean. East Coast birds migrated along the eastern seaboard of the U.S., through Florida, and across the Caribbean. Midwestern birds wintered from Mexico south to Bolivia (22.35 degreesN to 13.64 degreesS, and 91.75 degreesW to 61.76 degreesW), while East Coast birds wintered from Florida to as far south as Brazil (27.48 degreesN to 18.5 degreesS and 80.4 degreesW to 57.29 degreesW). Dates of departure from breeding areas differed significantly between sexes and geographic regions, with females leaving earlier than males. Western birds traveled a shorter distance than either midwestern or eastern Ospreys. Females traveled farther than males from the same population, which resulted in females typically wintering south of males.
... A summary of estimated osprey pairs nesting in each state was prepared FL, MD, NJ, NY, OH, SC 196426 26 Wiemeyer et al., 1980CT, MA, NJ, NY, WI 196925 Spitzer et al., 1977CT, NY 196968 Spitzer et al., 1978NJ 1970-197414 Wiemeyer et al., 1978FL 19723 Szaro 1978ID 197211 Johnson et al., 1975WY 19724 Swenson 1979MA, MD, VA 1973-198725 Audet et al., 1992FL 1974-19752 4 Sundlof et al., 1986IA, MA, MD, NC, NJ SC, VA, WI 197522 Wiemeyer et al., 1987CA 1977-198415 Littrell 1986MI 1980-198925 Ewins et al., 1999ID, OR, WA 1981-198612 Henny and Anthony 1989NJ 198917 Clark et al., 200113 Henny et al., 2003NC 199512 Augspurger et al., 1996WI 199235 Karasov & Meyer 2000WI 199235 Woodford et al., 1998OR, WA 19956 Elliott et al., 1998OR, WA 19916 Elliott et al., 2000OR, WA 199514 Elliott et al., 2001bOR, WA 1997 for 1981 (Henny, 1983) and again for 1994 (Houghton & Ryman, 1997). More recent surveys showed dramatic increases in nesting numbers of ospreys for both North America and Europe (Henny et al., 1991(Henny et al., , 2008cHenny & Kaiser, 1996;Meyberg et al., 1996;Ewins, 1997;Saurola, 1997;Henny & Anderson, 2004;Watts et al., 2004;Nygård et al., 2006;Saurola, 2005;Zachos & Schmölcke, 2006). Increases in nesting numbers now appear to be limited only by nest site availability, food resources, and perhaps exposure to contaminants in heavily polluted areas. ...
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In the United States, many fish and wildlife species have been used nationwide to monitor environmental contaminant exposure and effects, including carcasses of the bald eagle (Haliaeetus leucocephalus), the only top avian predator regularly used in the past. Unfortunately, bald eagles are sensitive to investigator intrusion at the nest. Thus, the osprey (Pandion haliaetus) is evaluated as a potential sentinel species for aquatic ecosystems. Several characteristics support the choice of the osprey as a sentinel species, including: (1) fish-eating diet atop the aquatic food web, (2) long-lived with strong nest fidelity, (3) adapts to human landscapes (potentially the most contaminated), (4) tolerates short-term nest disturbance, (5) nests spatially distributed at regular intervals, (6) highly visible nests easily located for study, (7) ability to accumulate most, if not all, lipophilic contaminants, (8) known sensitivity to many contaminants, and (9) nearly a worldwide distribution. These osprey traits have been instrumental in successfully using the species to understand population distribution, abundance, and changes over time; the effects of various contaminants on reproductive success; how contaminants in prey (fish on biomass basis) contribute to egg concentrations (i.e., biomagnification factors); and spatial residue patterns. Data summarized include nesting population surveys, detailed nesting studies, and chemical analyses of osprey egg, organ, blood, and feather samples for contaminants that bioaccumulate and/or biomagnify in aquatic food webs; and biochemical evaluations of blood and various organs. Studies in the United States, Canada, Mexico, Europe, and elsewhere have shown the osprey to be a useful sentinel species for monitoring selected environmental contaminants, including some emerging contaminants in lakes, reservoirs, rivers, and estuaries.
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The osprey (Pandion halieatus) declined globally in the mid-late 20th century due primarily to pesticide contamination that reduced reproduction. The species has recovered through much of its range, and its range in California has increased. The species has received limited attention in recent decades, despite recommendations that it be monitored as an environmental indicator. In 2021, we located a sample of 39 osprey occupied nests near the Sacramento River and at reservoirs and small ponds in central interior California and determined habitats used and reproductive success. Nearly one-third of nests were located within 100 m of waterbodies and 88% were within 1000 m. The median distance of nests from roads was 51 m. Thirty-four (87%) of occupied nests were on anthropogenic sites, including utility poles, poles erected for ospreys, transmission towers, light poles, and port structures. Only five nests (13%) were in trees and snags. Nearly half (48%) of nests were on platforms constructed on utility poles and on poles erected for ospreys, both placed to protect electrical systems. Water levels in reservoirs, and some small farm ponds, were lower than average in 2021 due to drought, while the Sacramento River and Port were less selected. Twenty-four (71%) of 34 adequately monitored nests were successful in fledging at least one young. Productivity averaged 1.27 young/occupied nest, suggesting a healthy population. Reproductive success differed significantly among nests at different water body types, with river-port, reservoir, and pond sites exhibiting high, moderate, and low productivity, respectively. Our results document a range expansion into central interior California, presumably in response to reduced pesticide levels, reservoir creation, and availability of anthropogenic nest sites. Results also suggest that drought, and thus predicted warming and drier climate, may disproportionately affect populations nesting at non-riverine habitats by reducing the amount foraging area and increasing the distance from nest sites to foraging areas.
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Although nesting on power line structures has benefited some raptor species, line operational problems have occurred, and utilities have implemented labor-intensive methods to combat bird nesting on their lines. Historically, methods have typically included direct nest removal and trimming of nesting materials. This approach often has been unsuccessful, and a number of utilities have ultimately concluded that accommodating bird nests is a more sound approach. Managing where raptors nest on utility structures has not only solved many operational problems, but it also has resulted in positive publicity for many line operators. There also are a variety of stick deflectors that can be used to discourage nesting. In distribution construction, engineered single crossarms are preferred over double' arms at potential nesting areas. A successful nest management program includes plans to make nearby lines raptor safe from electrocutions. The combination of providing nests with bird-friendly utility configurations can result in electric facilities enhancing wild raptor populations without impacting power reliability.
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CT.--Osprey (Pandion haliaetus) populations were monitored extensively in the Kawartha Lakes region of Ontario, Canada, from 1978-2000, and intensively monitored in a subsample of these lakes, particularly Sturgeon Lake, (1991-2001). The number of occupied nests within the Kawartha Lakes region increased from 18 nests in 1978 to 89 nests in 1992 following the ban of organochlorine pesticides and the provision of artificial nesting structures. Surveys in 1996 and 2000, however, revealed 78 and 66 occupied nests, respectively indicating a recent population decline or stabilization. The Osprey breeding colony at Sturgeon Lake followed very similar trends in nest numbers, peaking in the mid-1990s, followed by a decline and apparent population stabilization by 2001. The mean annual productivity in this colony between 1986 and 2001 was 1.17 chicks per occupied nest, and exceeded the reported replacement level of 0.8 chicks per nest. Population fluctuations and trends in overall annual production of fledglings were similar between the Sturgeon Lake breeding colony and birds breeding at lower densities in neighboring lakes. Estimated potential recruitment to the Sturgeon Lake colony, based on the number of fledglings produced 3-5 years previously was positively related to population size in a given year (r2 = 0.65); but very few banded nestlings returned to the colony as breeders. Factors affecting productivity and population trends seem to operate similarly at local and regional scales. As very few fledged juveniles returned to the Sturgeon Lake colony as breeders, yet the population was maintained, we suggest there was probably considerable dispersal of juveniles among local natal sites throughout the region.
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Usamos una técnica de muestreo doble (muestreos aéreos y terrestres) en 2006, con cobertura doble parcial, para estimar el tamaño poblacional actual de las poblaciones reproductivas de Pandion haliaetus en el noroeste de México (costa de Baja California, islas en el Golfo de California y las costas de Sonora y Sinaloa). Con excepción de las islas de Natividad, Cedros y San Benitos a lo largo de la costa pacífica de Baja California (las tres fueron excluidas de nuestra cobertura en 2006 debido a la niebla), este estudio repitió los muestreos que habíamos realizado con el mismo protocolo en 1977 y 1992/1993, lo que nos permitió estimar las tendencias poblacionales a nivel regional. El tamaño poblacional mínimo estimado para el área de estudio en 2006 fue de 1343 parejas anidando, lo que significa un aumento de 81% desde 1977, pero sólo de 3% desde 1992/1993. La población de Baja California del lado del Golfo permaneció generalmente estable durante los tres muestreos (255, 236 y 252 parejas, respectivamente). Las poblaciones de las Islas Midriff (Golfo de California, próximas a la latitud 29°N) permanecieron similares desde 1992/1993 (308 parejas) hasta 2006 (289 parejas), pero con cambios poblacionales notables en las dos islas más grandes (Ángel Guardián: 45 a 105 parejas [133% de aumento]; Tiburón: 164 a 109 parejas [34% de disminución]). El tamaño estimado mínimo de la población de P. haliaetus en Sonora continental disminuyó de manera similar al de la Isla Tiburón adyacente, i.e., en un 26%, desde 214 parejas en 1993 a 158 parejas en 2006. En contraste, la población en la costa de Sinaloa, que había disminuido en un 150% entre 1977 y 1993, creció de nuevo en un 58% entre 1993 y 2006, desde 180 hasta 285 parejas. Nuestros estudios confirmaron los patrones descriptos previamente de cambios poblacionales rápidos a escala local, junto con cambios aparentes en la distribución espacial. La gran población que nidifica en el suelo, que hasta hace poco anidaba en dos islas en la laguna San Ignacio (lado del Océano Pacífico, Baja California), no estuvo presente en las islas en 2006. Sin embargo, un número equivalente de parejas fue encontrado al norte y al sur de la laguna, anidando en pueblos y a lo largo de líneas eléctricas elevadas, sin un cambio global en el tamaño poblacional para esta área en general (198 parejas en 1992; 199 en 2006). El uso de estructuras artificiales de anidación fue de 4.3% en 1977 y de 6.2% en 1992/1993, pero aumentó a 26.4% en 2006. El uso de los postes que sostienen las líneas eléctricas elevadas representa un riesgo de electrocución para P. haliaetus y también causa cortes de energía e incendios. Recomendamos la modificación de estos postes para que puedan alojar de modo seguro los nidos de P. haliaetus, como se ha logrado exitosamente en muchos países.
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In the present study, large scale geographical variation in the occurrence of organohalogenated pollutants (OHPs) was investigated throughout Europe using eggs of a terrestrial resident passerine species, the blue tit (Cyanistes caeruleus). Blue tit eggs from 10 sampling locations, involving suburban, rural and remote areas, in 7 European countries were collected and analysed. Sum polychlorinated biphenyl (PCB) levels ranged from 150ng/g lipid weight (lw) to 2003ng/g lw. Sum polybrominated diphenyl ethers (PBDEs) ranged from 3.95ng/g lw to 114ng/g lw. As expected, PCB and PBDE concentrations were significantly higher in the sampled suburban locations compared to the rural and remote locations. Sum organochlorine pesticides (OCPs) ranged from 122ng/g lw to 775ng/g lw. OCP concentrations were, against the expectations, found to be lower in the rural sampling locations compared to the other locations. Contamination profiles of PCBs, PBDEs and OCPs differed also among the sampling locations, which may be due to local contamination sources. Finally, we compared the results of this study with previously reported OHP concentrations in the eggs of a closely related species, the great tit (Parus major), from the same sampling locations in Europe. We found no differences in concentrations between the species. In addition, we found a significant, positive correlation between the sum PCB concentrations in blue tit eggs and great tit eggs, suggesting similar exposure pathways, mechanisms of accumulation and maternal transfer of PCBs. In conclusion, our results suggest the usefulness of eggs from passerine birds as a biomonitoring tool for OHPs on a large geographical scale.
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Large-scale studies are essential to assess the emission patterns and spatial distribution of organohalogenated pollutants (OHPs) in the environment. Bird eggs have several advantages compared to other environmental media which have previously been used to map the distribution of OHPs. In this study, large-scale geographical variation in the occurrence of OHPs, such as polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorine pesticides (OCPs), was investigated throughout Europe using eggs of a terrestrial residential passerine species, the great tit (Parus major). Great tit eggs from 22 sampling sites, involving urban, rural and remote areas, in 14 European countries were collected and analysed (5-8 eggs per sampling site). The environmentally most important congeners/compounds of the analysed pollutants were detectable in all sampling locations. For PCBs, PBDEs and OCPs, no clear geographical contamination pattern was found. Sum PCB levels ranged from 143 ng/g lipid weight (lw) to 3660 ng/g lw. As expected, PCB concentrations were significantly higher in the sampled urban compared to the remote locations. However, the urban locations did not show significantly higher concentrations compared to the rural locations. Sum PBDEs ranged from 4.0 ng/g lw to 136 ng/g lw. PBDEs were significantly higher in the urbanized sampling locations compared to the other locations. The significant, positive correlation between PCB and PBDE concentrations suggests similar spatial exposure and/or mechanisms of accumulation. Significantly higher levels of OCPs (sum OCPs ranging from 191 ng/g lw to 7830 ng/g lw) were detected in rural sampling locations. Contamination profiles of PCBs, PBDEs and OCPs differed also among the sampling locations, which may be due to local usage and contamination sources. The higher variance among sampling locations for the PCBs and OCPs, suggests that local contamination sources are more important for the PCBs and OCPs compared to the PBDEs. To our knowledge, this is the first study in which bird eggs were used as a monitoring tool for OHPs on such a large geographical scale.
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Osprey (Pandion haliaetus) eggs were collected from 1991 to 1997 at nests (n = 121) upstream and downstream of bleached kraft pulp mills and at reference sites in the Fraser and Columbia River drainage systems of British Columbia, Washington, and Oregon. Blood samples were collected from nestling ospreys during the 1992 breeding season on the Thompson River. Samples were analyzed for polychlorinated dibenzo-p-dioxins (PCDDs) and -dibenzofurans (PCDFs). Mean concentrations of 2,3,7,8-TCDD were significantly higher in eggs collected in 1991 at downstream compared to upstream nests near pulp mills at Kamloops and Castlegar, British Columbia. There were no significant temporal trends in 2,3,7,8-TCDD, -TCDF or other measured compounds at a sample of nests monitored between 1991 and 1994 downstream of the Castlegar pulp mill, despite changes in bleaching technology (CIO2 substitution). However, by 1997 concentrations of 2, 3,7,8-TCDD and -TCDF were significantly lower than previous years in nests sampled downstream at both Castlegar and Kamloops. An unusual pattern of higher chlorinated PCDDs and PCDFs was found in many of the osprey eggs collected in this study, and considerable individual variation in the pattern existed among eggs from the same site. For example, eggs from four different nests at one study area (Quesnel) on the Fraser River had concentrations of 1,2,3,4,6,7,8-HpCDD ranging from <1 to 1,100 ng/kg and OCDD from <1 to 7,000 ng/kg wet weight. Higher mean concentrations of HpCDD and OCDD were found in eggs from the Thompson River, a tributary of the Fraser, compared to the Columbia River, and concentrations were generally higher at nests upstream of pulp mills. In plasma samples, 1,2,3,4,6,7,8-HpCDD and OCDD were the main compounds detected, with no significant differences measured between samples upstream versus downstream or earlier versus later in the breeding season. Use of chlorophenolic wood preservatives by lumber processors was considered the main source of higher chlorinated PCDD/Fs throughout the systems, based on patterns of trace PCDFs in eggs and significant correlations between egg concentrations of pentachlorophenol and both HpCDD (r = 0.891, p < 0.01) and OCDD (r = 0.870, p < 0.01).
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A migratory population of 78 pairs of Osprey (Pandion haliaetus) nesting along the Willamette River in western Oregon was studied in 1993. The study was designed to determine contaminant concentrations in eggs, contaminant concentrations in fish species predominant in the Ospreys diet, and Biomagnification Factors (BMFs) of contaminants from fish species eaten to Osprey eggs. Ten Osprey eggs and 25 composite samples of fish (3 species) were used to evaluate organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs), and polychlorinated dibenzofurans (PCDFs). Mercury was also analyzed in fish. Geometric mean residues in Osprey eggs were judged low, e.g., DDE 2.3 microg g(-1) wet weight (ww), sigma PCBs 0.69 microg g(-1), 2,3,7,8-TCDD 2.3 ng kg(-1), and generally well below known threshold values for adverse effects on productivity, and the population was increasing. Osprey egg residue data presented by River Mile (RM) are discussed, e.g., higher PCDDs were generally found immediately downstream of paper mills and eggs from the Willamette River had significantly elevated PCBs and PCDDs compared to reference eggs collected nearby in the Cascade Mountains. Prey remains at nest sites indicated that the Largescale Sucker (Catostomus macrocheilus) and Northern Pikeminnow (Ptychocheilus oregonensis) accounted for an estimated 90.1% of the biomass in the Osprey diet, and composite samples of these two species were collected from different sampling sites throughout the study area for contaminant analyses. With the large percentage of the fish biomass in the Osprey diet sampled for contaminants (and fish eaten by Ospreys similar in size to those chemically analyzed), and fish contaminant concentrations weighted by biomass intake, a mean BMF was estimated from fish to Osprey eggs for the large series of contaminants. BMFs ranged from no biomagnification (0.42) for 2,3,7,8-TCDF to 174 for OCDD. Our findings for the migratory Osprey were compared to BMFs for the resident Herring Gull (Larus argentatus), and differences are discussed. We believe a BMF approach provides some basic understanding of relationships between contaminant burdens in prey species of fish-eating birds and contaminants incorporated into their eggs, and may prove useful in understanding sources of contaminants in migratory species although additional studies are needed.
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The Chesapeake Bay osprey population has more than doubled in size since restrictions were placed on the production and use of DDT and other toxic organochlorine contaminants in the 1970s. Ospreys are now nesting in the most highly polluted portions of the Bay. In 2000 and 2001, contaminant exposure and reproduction were monitored in ospreys nesting in regions of concern, including Baltimore Harbor and the Patapsco River, the Anacostia and middle Potomac rivers, and the Elizabeth River, and a presumed reference site consisting of the South, West, and Rhode rivers. A "sample egg" from each study nest was collected for contaminant analysis, and the fate of eggs remaining in each nest (n = 14-16/site) was monitored at 7- to 10-day intervals from egg incubation through fledging of young. Ospreys fledged young in regions of concern (observed success: 0.88-1.53 fledglings/active nest), although productivity was marginal for sustaining local populations in Baltimore Harbor and the Patapsco River and in the Anacostia and middle Potomac rivers. Concentrations of p,p'-DDE and many other organochlorine pesticides or metabolites, total PCBs, some arylhydrocarbon receptor-active PCB congeners and polybrominated diphenyl ether congeners, and perfluorooctanesulfonate were often greater in sample eggs from regions of concern compared to the reference site. Nonetheless, logistic regression analyses did not provide evidence linking marginal productivity to p,p'-DDE, total PCBs, or arylhydrocarbon receptor-active PCB congener exposure in regions of concern. In view of the moderate concentrations of total PCBs in eggs from the reference site, concerns related to new and emerging toxicants, and the absence of ecotoxicological data for terrestrial vertebrates in many Bay tributaries, a more thorough spatial evaluation of contaminant exposure in ospreys throughout the Chesapeake may be warranted.
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Temporal, spatial, and interspecific trends in polybrominated diphenyl ether (PBDE) flame retardants were determined in eggs of marine and freshwater bird species from the province of British Columbia, Canada. Temporal trends in the Fraser River estuary, 1983-2002, were examined by analysis of eggs of great blue herons (Ardea herodias) and from the Strait of Georgia marine ecosystem, 1979-2002, in eggs of double-crested cormorants (Phalacrocorax auritus). Results were compared to those from eggs of the osprey (Pandion haliaetus) taken along the lower Fraser River and along the Columbia River near Castlegar, British Columbia, and of a pelagic seabird, the Leach's storm-petrel (Oceanodroma leucorhoa), collected at a colony on the Queen Charlotte Islands. Mean concentration of sigmaPBDE, 455 microg/kg w.w., were highest in heron eggs collected in 2002 from the Fraser estuary. Concentrations in eggs of cormorants and ospreys taken from sites of varying urban influence tended to be about half that value. Leach's storm petrel eggs had only trace amounts of sigmaPBDE (3.38 microg/kg), despite having similar concentrations of PCBs and organochlorine pesticides to the other species. PBDEs increased exponentially with a doubling time of 5.7 years in eggs of both herons and cormorants. Over this period of increasing PBDEs, major chlorinated hydrocarbons, such as PCBs and DDE, were stable or decreased. The PBDE pattern was relatively consistent in most years and sites, with BDEs 47 > 100 > 99 > 153 > 154 > 28 > 183. This was interpreted as evidence of technical pentaBDE formulations as primary sources of the contamination, with the octaBDE formulations as secondary. Higher resolution analysis of a subsample of the eggs revealed the presence of up to nine other congeners, including BDE209 (range: 0.9-1.8 microg/kg), indicating exposure and uptake of decaBDE sourced congeners in North American foodchains. At some locations, concentrations of pentabrominated congeners and mixtures in fish are approaching levels potentially toxic to fish-eating birds, based on rodent studies and calculations of dietary intake from fish data.
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The osprey (Pandion haliaetus) population nesting along the lower portion of the Columbia River (river mile 29 to 286) increased from 94 in 1997 to 103 occupied nests in 1998 (9.6% annual rate of increase) to 225 occupied nests in 2004 (13.9% annual rate of increase). The more recent rate of population increase was associated with higher reproductive rates than in 1997/1998, and significantly lower egg concentrations of most organochlorine (OC) pesticides, polychlorinated biphenyls (PCBs), polychlorinated dibenzo-p-dioxins (PCDDs) and polychlorinated dibenzofurans (PCDFs). A comparison of observed egg residue concentrations in 2004 with effect-level information for ospreys indicated that reproduction at few, if any, nests was adversely affected. As recent as 1997/1998, dichlorodiphenyldichloroethylene (DDE) was still adversely affecting reproductive success for a portion of this population. Mercury was the only contaminant evaluated in both 1997/1998 and 2004 that showed a significant increase in eggs over time, but concentrations in 2004 (0.09 microg g(-1) ww) remained below established effect levels for birds (generally reported at 0.50 microg g(-1) ww or higher). The significant increase in mercury justifies the need for future monitoring. All contaminants mentioned that biomagnify up food chains can be effectively monitored in osprey eggs. The osprey has been shown to be an excellent sentinel species for long-term monitoring with their many useful traits described.
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