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Organochlorines in Black-Crowned Night Heron (Nycticorax nycticorax) Eggs Reflect Persistent Contamination in Northeastern US Estuaries

  • U.S. Fish and Wildlife Service, Anchorage, AK, United States

Abstract and Figures

Colonially nesting aquatic birds can indicate site-specific contamination because they are high-level predators and dependent upon local resources during the breeding season. We compared persistent organochlorine concentrations in black-crowned night heron (Nvcticorax nvcticorax) eggs collected in 1992-93 among areas of known contamination (New York Harbor, Boston Harbor, Cape Cod, and Delaware Bay) and a reference site (Nantucket Island) in the northeastern United States (7-16 eggs/site). Total PCBs, p,p'-DDE, oxychlordane, heptachlor epoxide, and trans-nonachlor were detected in most eggs and were significantly higher in New York Harbor compared to all other sites (ANOVA on factor scores from the first principal component, which accounted for 75% of data variance, p < 0.0001). New York also had the highest contamination index (the number of Superfund sites within 20 km of the colony) among the sites. Nantucket, the reference site, had consistently low contamination in eggs, and the lowest contamination index. We conclude that black-crowned night heron eggs are useful indicators of site-specific persistent organochlorine contamination, as indexed by the number of nearby Superfund sites.
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Organochlorines in Black-Crowned Night Heron (Nycticorax nycticorax) Eggs
Reflect Persistent Contamination in Northeastern US Estuaries
A. C. Matz, K. C. Parsons
Manomet Center for Conservation Sciences, P.O. Box 1770, Manomet, Massachusetts 02345, USA
Received: 21 November 2002 /Accepted: 5 June 2003
Abstract. Colonially nesting aquatic birds can indicate site-
specific contamination because they are high-level predators
and dependent upon local resources during the breeding sea-
son. We compared persistent organochlorine concentrations in
black-crowned night heron (Nycticorax nycticorax) eggs col-
lected in 1992–93 among areas of known contamination (New
York Harbor, Boston Harbor, Cape Cod, and Delaware Bay)
and a reference site (Nantucket Island) in the northeastern
United States (7–16 eggs/site). Total PCBs, p,p-DDE, oxy-
chlordane, heptachlor epoxide, and trans-nonachlor were de-
tected in most eggs and were significantly higher in New York
Harbor compared to all other sites (ANOVA on factor scores
from the first principal component, which accounted for 75%
of data variance, p0.0001). New York also had the highest
contamination index (the number of Superfund sites within 20
km of the colony) among the sites. Nantucket, the reference
site, had consistently low contamination in eggs, and the lowest
contamination index. We conclude that black-crowned night
heron eggs are useful indicators of site-specific persistent or-
ganochlorine contamination, as indexed by the number of
nearby Superfund sites.
If females are nonmigratory or arrive well in advance of laying,
eggs of colonially nesting birds are excellent indicators of
ecosystem contamination because these birds are often at a
high trophic level, dependent upon foraging areas near their
colony during the breeding season, and philopatric (Custer et
al. 1991; Kushlan 1993). Contaminant exposure in colonially
nesting wading birds (Ciconiiformes) have been associated
with spatial differences in agricultural chemical use (Parsons et
al. 2000), heavy metals (Fitzner et al. 1995), and dioxins and
furans associated with paper mills (Elliott et al. 1989; Henshel
et al. 1995). Specifically, black-crowned night herons (BCNH)
(Nycticorax nycticorax) have been used to indicate localized
persistent organochlorine (OC) contamination at sites through-
out North America (Ohlendorf 1981; Henny et al. 1984; Henny
and Blus 1986; Hoffman et al. 1986; Rattner et al. 1993, 1994;
Blus et al. 1997). They are primarily piscivorous (Davis 1993),
their foraging range is generally less than 25 km from the
colony (Hoefler 1979), and they arrive at breeding sites in the
northeastern United States approximately one month before
laying (Burger 1978).
We measured persistent OC contaminants in BCNH eggs
collected from colonies in four northeastern US estuaries (Bos-
ton Harbor, Cape Cod, New York Harbor, and Delaware Bay),
and from Nantucket Island, a nonestuarine offshore island, in
1992–93. Our objective was to determine if differences in
contaminant concentrations among the sites in BCNH eggs
were reflected in a site environmental quality index, the num-
ber of Comprehensive Environmental Response, Compensa-
tion, and Liabilities Act National Priorities List (Superfund)
sites within a 20-km radius of the colony.
Materials and Methods
Study Areas
We collected BCNH eggs in 1992–93 under appropriate state and
federal permits from colonies in New York Harbor and Cape Cod, and
in 1993 from Boston Harbor, Delaware Bay, and Nantucket. The New
York Harbor colonies were on non-barrier dredge spoil islands located
between Staten Island, New York and New Jersey in the Arthur Kill
(Prall’s Island, 40°36N 74°12W, and Isle of Meadows, 40°34N
74°12W), and managed by the City of New York. The Cape Cod
colony was on a barrier island (Sampson’s Island, 41°37N 70°25W)
managed as a wildlife refuge by the town of Barnstable, Massachu-
setts, off the south shore of Cape Cod. The surrounding area was
largely residential, except for cranberry farms and the Massachusetts
Military Reservation, a source of volatile organic compounds, PCBs,
and pesticides (, approximately 10 km to the
northwest. The Boston Harbor colony was on one of approximately 30
drumlin islands in Boston Harbor (Middle Brewster Island, 42°20N
70°53W), managed by the National Park Service. The Delaware Bay
colony was on Pea Patch Island (39°35N, 75°34W) located in upper
Delaware Bay, and owned and managed by the State of Delaware.
Surrounding land uses included industry, agriculture, and residential
development. The reference colony was on a barrier beach peninsula
(Coatue, 41°17N 70°06W) on the north shore of Nantucket Island,
Correspondence to: A. C. Matz at present address; U.S. Fish and
Wildlife Service, 101-12th Ave., Box 19, Room 110, Fairbanks, AK
99701, USA; email:
Arch. Environ. Contam. Toxicol. 46, 270 –274 (2004)
DOI: 10.1007/s00244-003-2265-9
© 2004 Springer-Verlag New York Inc.
MA, managed by the Nantucket Conservation Foundation. Forty per-
cent of the land area of Nantucket was open space; the remainder was
residential and agricultural.
Sample Collection
One egg per nest was collected during incubation from 7–16 nests
randomly distributed throughout each colony. Egg contents were re-
moved using chemically clean instruments, placed in chemically clean
jars, stored frozen, then shipped frozen via overnight mail to the
analytical laboratory. We rinsed eggshells with water, air-dried them
for at least four weeks, then averaged 3–5 (0.005 mm) thickness
measurements taken over intact membranes at the equator with a
modified Starrett micrometer (L.S. Starrett Co., Athol, MA).
Analytical Chemistry
Egg contents were analyzed for 20 OC pesticides and metabolites and
total polychlorinated biphenyls (PCBs) as the sum of Aroclors (1242,
1248, 1254, and 1260), at Mississippi State Chemical Laboratory,
Mississippi State, MI, using established methods (Environmental Pro-
tection Agency 1980). Briefly, samples were mixed with anhydrous
sodium sulfate, soxhlet-extracted with hexane, dried, dissolved in
petroleum ether and extracted with acetonitrile saturated with petro-
leum ether. Residues partitioned into petroleum ether were transferred
to a Florisil glass column, then eluted with 6% diethyl ether/94%
petroleum ether (Fraction I, plus three additional fractions), followed
by 200 mL 15% diethyl ether/85% petroleum ether (Fraction II). Both
fractions were concentrated and Fraction I transferred to a silicic acid
column to separate PCBs, the residues were quantified by packed or
megabore column electron capture gas chromatography. Detection
limits were 0.01 g/g wet weight (ww) for pesticides and 0.05 g/g
ww for PCBs. No analytes were detected in procedural blanks. Spike
recoveries were within 70 –120%, except PCB 1260 in 1993 (57%) and
HCB (63% and 65% in 1992 and 1993, respectively). Relative percent
differences between duplicates were 12%.
Data Analysis
Contaminants that were detected in 90% of samples at all sites were
analyzed using multivariate analyses (Sparks et al. 1999) to control the
increased Type I error rate inherent in multiple univariate tests, and to
discern patterns or relationships not evident from univariate testing
(yet allow for examination of individual variables and post-hoc test-
ing). Analyte concentrations were corrected for moisture loss that
occurs during incubation (Stickel et al. 1973), the few non-detections
were substituted with a random number between zero and the detection
limit, and data were log-transformed to reduce heteroscedasticity and
achieve normality. Residues were not lipid-adjusted, as none were
significantly correlated with egg lipid content (Hebert and Keenleyside
1995). Data were then reduced to the principal components (PCs) that
accounted for 75% of the variance within the data. We used Analysis
of Variance (ANOVA) with PC factor scores as the dependent vari-
ables to test for differences among sites (Jackson 1991), with Bonfer-
roni-adjusted post-hoc testing. Eggshell thickness was also tested for
differences among sites (ANOVA), and for significant correlation with
p,p-DDE (-4,4-dichlorodiphenyl dichloroethene) concentrations
(Pearson’s r). Unless otherwise stated, ␣⫽0.05. Data were analyzed
with SYSTAT 7.0 and 8.0 (SPSS, Inc., Chicago, IL), and SAS 8.0
(SAS Institute, Inc., Cary, NC).
Contamination Index
There are many environmental quality indices for coastal and estuarine
sites, including monitoring programs such as the National Oceanic and
Atmospheric Administration’s (NOAA) Mussel Watch, sediment sam-
pling by state agencies, and the United States Environmental Protec-
tion Agency’s (USEPA) integrative Index of Watershed Indicators.
However, none were performed identically near all of the sampled
BCNH colonies. We therefore used the number of Superfund sites
within a 20-km radius of the colony, obtained from USEPA’s Super-
fund website ( Sites included those with
PCBs or OC pesticides as primary contaminants of concern, and
landfills, which often have PCB or OC contamination. We graphically
compared this index to differences in BCNH egg contamination
among sites.
We collected 7 BCNH eggs from Boston Harbor, 7 from
Delaware Bay, 16 from Cape Cod, 11 from New York Harbor,
and 8 from Nantucket. Only oxychlordane, heptachlor epoxide,
trans-nonachlor, p,p-DDE, and total PCBs (sum of Aroclors
1242, 1248, 1254, and 1260) were detected in 90% of sam-
ples at all sites. These contaminants were significantly different
among sites (ANOVA with factor scores from the first PC,
accounting for 75% of total variance and with factor loadings
0.85, p0.0001), with greater contaminant concentrations
at New York compared to all other sites (Table 1). The number
of Superfund sites with PCBs or OCs as primary contaminants
of concern also reflected PCB, DDE (Figure 1a), oxychlordane,
heptachlor epoxide, and trans-nonachlor contamination among
the sites, although inclusion of landfills increased Delaware
Bay’s index relative to the other sites (Figure 1b). Other
contaminants, which were not consistently detected (i.e., in
90% of samples at one or more sites), were summarized
according to percent detections; some were found only in eggs
from New York Harbor or Cape Cod (Table 2).
Eggshell thickness was not different among estuaries (p
0.350), and was negatively correlated with p,p-DDE concen-
trations (Pearson r⫽⫺0.466, n48, p0.001) (New York
n10 for this analysis only). Mean eggshell thickness at all
colonies (0.263 0.024 mm) was 4.4% thinner than the
pre-1947 norm (0.275 0.002 mm, n142 eggs from
western US; Henny et al. 1984).
Organochlorine contaminants detected in BCNH eggs reflected
the environmental quality index (the number of nearby Super-
fund sites). In spite of the relatively small sample sizes, New
York Harbor, which had the highest number of PCB/pesticide
and landfill Superfund sites near the colony, consistently had
the highest concentrations of persistent OC contaminants, and
some contaminants detected in New York Harbor eggs were
detected nowhere else. In contrast, the offshore site on Nan-
tucket, with no nearby Superfund sites, consistently had the
lowest contaminant concentrations. Trends from highest to
lowest contamination (Figure 1) initially appear to reflect in-
creasing urbanization and associated industries, with two ex-
OCs in Black-Crowned Night Heron Eggs 271
ceptions. The Cape Cod colony was in a non-urban watershed,
but was close to Otis Air National Guard/Camp Edwards (the
Massachusetts Military Reservation), a heavily contaminated
Superfund site (
Air National Guard (USAF)). Delaware Bay had a large num-
ber of surrounding landfills, which have a variety of contami-
nants of concern. Exposure to other contaminants have been
documented at Pea Patch Island (Parsons et al. 2000; Rattner et
al. 2000).
Black-crowned night-heron populations have declined in
Table 1. Wet weight concentrations
of persistent organochlorine contaminants in black-crowned night heron eggs collected from five north-
eastern US sites,
Delaware Bay
Boston Harbor
Cape Cod
New York
oxychlordane 0.01 (ND–0.09) 0.02 (ND–0.03) 0.02 (0.01–0.04) 0.03 (ND–0.37) 0.06 (ND–0.23)
heptachlor epoxide 0.01 (ND–0.04) 0.01 (ND–0.02) 0.01 (ND–0.03) 0.01 (ND–0.15) 0.03 (ND–0.11)
trans-nonachlor 0.02 (ND–0.09) 0.03 (0.02–0.05) 0.05 (0.03–0.11) 0.05 (ND–0.54) 0.06 (ND–0.41)
total PCBs 1.47 (0.71–3.26) 3.03 (0.93–6.46) 3.83 (2.02–13.21) 5.35 (1.88–40.73) 6.98 (0.19–33.91)
p,p-DDE 0.61 (0.17–9.45) 1.00 (0.68–1.55) 0.54 (0.35–1.36) 1.24 (0.19–12.72) 2.07 (0.07–
Given are geometric mean (and range), g/g, where ND is not detected at nominal detection limits of 0.01 g/g for pesticides and 0.05 g/g
for PCBs. Data were adjusted for moisture changes associated with development.
Unlike superscripts indicate significant differences among colonies (ANOVA on factor scores from the principal component that accounted for
75% of data variance, p0.0001).
Fig. 1. (a) Geometric mean concentrations of total PCBs and p,p-DDE (g/g wet weight) in black-crowned night-heron eggs from five sites in
the northeastern US, 1992–93. (b) The number of Comprehensive Environmental Response, Compensation, and Liabilities Act National Priorities
List (Superfund) sites within 20 km of the nesting colonies where the eggs were collected. Superfund sites included those with PCBs or pesticides
listed as primary contaminant of concern and landfills, which often have PCB or organochlorine pesticide contamination
272 A. C. Matz and K. C. Parsons
North America (Davis 1993), due in part to OC contaminants.
In this study, 8% of eggs had p,p-DDE 8 ppm (one each at
Cape Cod and Nantucket, and two at New York Harbor), which
Henny et al. (1984) associated with lower productivity in
western U.S. colonies. In spite of a significant relationship
between p,p-DDE concentrations and eggshell thickness, how-
ever, p,p-DDE residues in this study were far below the 50
ppm associated with 20% decrease in eggshell thickness by
Henny et al. (1984). Total PCB concentrations (Table 1) from
the more contaminated sites approached concentrations found
in a contaminated site in Green Bay, WI (geometric mean of
9.32 g/g ww), where there were linear relationships between
total PCBs (as well as toxic equivalents and PCB congeners)
and hepatic cytochrome P450-associated monooxygenase ac-
tivities and P450 proteins (Rattner et al. 1994). Similar con-
centrations were correlated with decreased body weight at
hatching in pipping BCNH embryos from colonies in San
Francisco Bay (averages of 1.54 and 3.43 g/g ww) (Hoffman
et al. 1986).
More recent measurements of persistent contaminants in
BCNH embryos indicate decreasing concentrations through
time, however (Blus et al. 1997; Rattner et al. 2000). Ad-
ditionally, differential productivity at the study sites (except
Nantucket) was attributed to predation, starvation, and other
contaminants in addition to persistent OCs (Parsons et al.
2001), and Blus et al. (1997) concluded that establishment
of predators near BCNH colonies lead to decreased produc-
Even with concentrations below effect levels, high trophic
status and colony philopatry ensure the utility of BCNH and
other wading birds as indicators of estuarine quality, which
includes environmental contaminants. Specifically, we found
that BCNH eggs reflected persistent organochlorine contami-
nation, as indexed by the number of nearby Superfund sites, in
northeastern US estuarine and coastal sites.
Acknowledgments. Funding and logistical assistance were pro-
vided by the US Fish and Wildlife Service New England Field
Office, Delaware Department of Natural Resources and Environ-
mental Control, New York City Audubon Society, New York City
Department of Parks, Nantucket Conservation Foundation, Geral-
dine R. Dodge Foundation, Massachusetts Audubon Society, Bos-
ton Harbor Islands State Park, Island Foundation, and Manomet
members. We also thank Drew Major and Ken Carr of the US Fish
and Wildlife Service, and Manomet Program Manager Amanda
McColpin for project assistance, and two anonymous reviewers.
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Table 2. Percent of black-crowned night heron eggs collected from
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taminants were detected
New York
toxaphene 0.0 0.0 0.0 0.0 0.0
0.0 0.0 14.3 25.0 18.2
-HCH 0.0 0.0 0.0 0.0 27.3
-HCH 0.0 0.0 0.0 43.8 54.5
o,p-DDE 0.0 0.0 0.0 25.0 9.1
-chlordane 12.5 14.3 100.0 6.3 0.0
0.0 0.0 0.0 18.8 72.7
12.5 0.0 0.0 6.3 9.1
12.5 71.4 100.0 93.8 54.5
cis-nonachlor 75.0 100.0 100.0 62.5 36.4
p,p-DDD 50.0 100.0 100.0 93.8 100.0
p,p-DDT 37.5 28.6 71.4 37.5 72.7
0.0 28.6 42.9 25.0 63.6
Nominal detection limits were 0.01 g/g wet weight.
OCs in Black-Crowned Night Heron Eggs 273
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274 A. C. Matz and K. C. Parsons
... PCBs are persistent and bioaccumulative, and have been commonly detected in herons in North America. More recently, for example, PCBs have been observed in great blue herons (GBH, Ardea herodias; Straub et al., 2007) and blackcrowned-night herons (BCNH, Nycticorax nycticorax; Levengood et al., 2007) in Illinois, USA; GBH along the St. Lawrence River in Quebec, Canada (Champoux et al., 2006); BCNH and great egrets (Ardea alba) in coastal California (Henny et al., 2008), and BCNH in coastal northeastern USA (Matz and Parsons, 2004). PCB exposure in herons has been associated with: increased cytochrome P450 monooxygenase activity Levengood et al., 2007); reduced embryonic weight (Hoffman et al., 1986), reduced plasma retinol concentrations (Champoux et al., 2006), and, in combination with DDE, decreased nest attentiveness (Thomas and Anthony, 2003). ...
... BCNH begin to arrive at the Lake Calumet colony in late March and clutch initiation starts during the third week of April and continues into late May and early June (Levengood et al., 2005). This would seem to allow ample time to replace lipids lost during migration with locally-derived sources (Kelly et al., 1993;Matz and Parsons, 2004), which may contain elevated concentrations of environmental contaminants. ...
We compared polychlorinated biphenyl (PCB) congener profiles of embryos of black-crowned night-herons (Nycticorax nycticorax) nesting in an urban-industrialized area of Chicago, Illinois, USA with those of regurgitated food boluses from nestlings and their primary prey. Consistent with previous studies of piscivorous birds, the PCB burden of embryos was shifted towards more heavily chlorinated congeners (those with 6, 7, and 8 chlorines), when compared to prey. The PCB congener profiles for measured and homolog concentrations in alewife (Alosa pseudoharengus) collected from Lake Michigan at the Chicago, Illinois, waterfront, closely resembled that of regurgitated food boluses collected from nestlings at the Lake Calumet colony. Also, alewife from Illinois and regurgitates were not clearly differentiated by the discriminant analyses for measured, proportional, and homolog concentrations. Congener profiles in alewife from the highly contaminated Indiana Ship Canal, which had a much higher PCB burden (geometric average = 1061.7 ng/g ww [95% CI = 648.6–1061.7 ng/g ww]) than did alewife from Illinois (158.1 [135.8–184.5]ng/gww) and regurgitates (212.3 [177.0–254.7]ng/g ww), reflected a less-chlorinated mixture (i.e., Aroclor 1242). These results are consistent with our observations, which indicated that many of the adults of this colony were foraging along the Chicago waterfront, where alewife had lower PCB burdens. Because the congener patterns of the prey differ, the PCB congener profiles can be used to elucidate foraging patterns of colonial piscivorous birds and determine relative risks to exposed populations.
... Environmental contamination by pollutants such as pesticides (especially persistent organochlorines), heavy metals and polychlorinated biphenyls (Brisbin 1993;Furness 1993;Wren et al. 1994;Dauwe et al. 2002;Mochizuki et al. 2002;Boncompagni et al. 2003;Matz & Parsons 2004;DeWitt et al. 2006;Papp et al. 2007). ...
... Mean DDE concentrations in New York gulls (0.033 ug/g) were much lower than pooled DDE concentrations at the Great Lakes sites (0.158 À 0.505 ug/g) and marginally lower than at the reference site (0.059 ug/g) in Fox et al. [25], suggesting that the negative correlation between DDE and PHA response in New York birds may not be causal but instead the result of co-correlation between DDE and immunotoxic dioxins and PCBs. Although no tissues were collected for contaminant analysis in blackcrowned night herons in the present study, significant concentrations of dioxins and PCBs have been reported previously in the eggs of this species nesting in and near the Hudson Raritan Estuary [38]. Laboratory studies with chickens have shown that birds can be susceptible to immunotoxic effects at exposures similar to those observed in herring gulls from lower New York Harbor. ...
Previous studies have shown inexplicable declines in breeding waterbirds within western New York/New Jersey Harbor between 1996 and 2002 and elevated polychlorinated dibenzo-p-dioxins and polychlorinated biphenyls (PCBs) in double-crested cormorant (Phalacrocorax auritus) eggs. The present study assessed associations between immune function, prefledgling survival, and selected organ chlorine compounds and metals in herring gulls (Larus argentatus) and black-crowned night herons (Nycticorax nycticorax) in lower New York Harbor during 2003. In pipping gull embryos, lymphoid cells were counted in the thymus and bursa of Fabricius (sites of T and B lymphocyte maturation, respectively). The phytohemagglutinin (PHA) skin response assessed T cell function in gull and heron chicks. Lymphocyte proliferation was measured in vitro in adult and prefledgling gulls. Reference data came from the Great Lakes and Bay of Fundy. Survival of prefledgling gulls was poor, with only 0.68 and 0.5 chicks per nest surviving to three and four weeks after hatch, respectively. Developing lymphoid cells were reduced 51% in the thymus and 42% in the bursa of gull embryos from New York Harbor. In vitro lymphocyte assays demonstrated reduced spontaneous proliferation, reduced T cell mitogen-induced proliferation, and increased B cell mitogen-induced proliferation in gull chicks from New York Harbor. The PHA skin response was suppressed 70 to 80% in gull and heron chicks. Strong negative correlations (r = -0.95 to -0.98) between the PHA response and dioxins and PCBs in gull livers was strong evidence suggesting that these chemicals contribute significantly to immunosuppression in New York Harbor waterbirds. Environ. Toxicol. Chem. © 2012 SETAC.
... The adverse effects of organochlorine compounds (OC) on the reproductive success of different wild species have been documented since the mid-1950s. Many studies have confirmed the existence of a direct relationship between the egg content of p,p 0 -DDE, a degradation product of DDT (dichloro-diphenyl-trichloroethane), and eggshell thinning (Forsyth et al., 1994;Clarke et al., 2001;Mañosa et al., 2003;Matz and Parsons, 2004). However, although p,p 0 -DDE is currently considered the main agent responsible for eggshell thinning, its mechanism of action is not completely understood. ...
Eggs of the Great Crested Grebe (Podiceps cristatus) were collected from a breeding area on Lake Maggiore (Northern Italy) from 2001 to 2005 in the vicinity of a p,p'-DDT manufacturer, whose production was stopped in 1996. DDT homologue and PCB congener levels were determined and compared to levels in eggs collected from other breeding areas on Lake Maggiore and in a presumably less contaminated area on Lake Garda. Although Lake Garda eggs on average possessed a lower level of p,p'-DDE than Lake Maggiore eggs, they had significantly higher levels of PCBs and could not be used as a reference population for the measurement of eggshell thickness. Nevertheless, a negative linear relationship was found between p,p'-DDE concentration and eggshell thickness for eggs collected from both lakes, indicating a possible causal relationship. Testosterone and 17beta-estradiol concentrations were also determined for eggs collected from both lakes in 2004. Average concentrations of both hormones were the lowest in eggs from Lake Maggiore; however, the very high variability within broods did not result in any significant difference between the lakes.
... herodias) from Canada (Laporte, 1982), 8-13%, 5.1-10.5%, and 4.4% in blackcrowned night-herons from the USA (Ohlendorf and Marouis, 1990;Matz and Parsons, 2004), African fish eagle in Zimbabwe by 11-20% (Douthwaite, 1989), peregrine falcon in Zimbabwe by 10% (Hartley et al., 1995), lanner falcon and bateleur (Terathopius ecaudatus) 8.8% and 10%, respectively, in South Africa (Snelling et al., 1984). In a review on birds and pesticides, found that a mean reduction in eggshell thickness of >18% is associated with population declines. ...
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During the last 15 years, no research has been published on the levels of pesticides in bird eggs from South Africa, despite the high levels found previously. We analysed eggs from African darter, cattle egret, reed cormorant, African sacred ibis, as well as single eggs from some other species, and found HCB, DDTs, HCHs, chlordanes and PCBs at detectable levels. The presence of mirex in all species was unexpected, since this compound was never registered in South Africa. It also seemed as if terrestrial feeding birds had higher DDE:PCB ratios when compared with aquatic feeding birds. Except for chlordane, the African darter eggs had the highest levels of all other compounds (mean 370 and 300 ng g(-1) ww Sigma pesticides and Sigma PCBs, respectively). Multivariate analysis clearly distinguished the aquatic and terrestrially feeding birds on pollution profile. The African darter (aquatic feeding) and the cattle egret (terrestrial feeding) would be good indicator candidates. Eggshell thinning was detected in the African darter, and was associated with most of the compounds, including DDE and PCBs. We raise a concern that generally longer living birds in warmer climates, laying fewer eggs per clutch, might be at increased risk when compared with trophically similar birds exposed to equivalent levels of pollution in colder climates. Given the scarcity of water and the high biodiversity in Southern Africa, climate change will exert strong pressure, and any additional anthropogenic contamination at levels that can cause subtle behavioural, developmental and reproductive changes, can have serious effects.
American Quarterly 51.4 (1999) 871-881 A small unframed photograph was one of the last artifacts a visitor saw at the Chicago showing of The Last Best Hope of Earth: Abraham Lincoln and the Promise of America. Measuring about three by four inches, it showed the assassinated president lying in state in New York's City Hall guarded by two soldiers. In the dim light, the visitor strained to see the details of this somber faded image -- to make out the features of Lincoln's face -- and learned from the adjacent label that this was the only such photograph to survive. Secretary of War Edwin M. Stanton (who stood at Lincoln's deathbed and coined the phrase "Now he belongs to the ages"), upon hearing that photographs had been taken of the late president ordered that all negatives and prints be seized and destroyed. Yet the forbidden image was later found in Stanton's personal papers; the Secretary had violated his own order. Stanton's action attests to the power of the collecting impulse, the desire to possess an object that provides a connection to Lincoln. Similar desires may have attracted visitors to this show. They may have come to stand in the presence of documents written by his hand, of his top hat and eyeglasses, to see, if not possess, artifacts associated with Lincoln. And visitors were not disappointed at the wealth of things to see. Among the rarities displayed were such diverse items as an autograph manuscript of the Gettysburg Address, the gloves and handkerchief Lincoln carried to Ford's Theatre on the night of his assassination, racist anti-Lincoln books and pamphlets, campaign posters, numerous letters to friends, family, generals, legal and political associates, and sets of White House silver and china. But the curators of this exhibition intended to provide much more for us than simply a chance to see a large collection of Lincolniana. The show's title, The Last Best Hope of Earth, was taken from Lincoln's Annual Message to Congress, delivered in December 1862 during the depths of the Civil War. In it he said, "we know how to save the Union. . . . In giving freedom to the slave, we assure freedom to the free--honorable alike in what we give, and what we preserve. We shall nobly save, or meanly lose, the last best, hope of earth." In Lincoln's view, the United States was the world's "last best hope" for democracy, freedom, republican government and economic opportunity. This exhibition sought to demonstrate how Lincoln developed these ideas in the context of the political events and social issues of his time. Thus, the show favored the written word. As James McPherson stated in the catalog's "Foreward," the answers to what exactly Lincoln meant by the "last best hope" "lie in the letters, speeches, and other documents" contained in the exhibition. The curators went on to state that the show "is a library exhibit which relies primarily on documents -- original manuscripts and rare printed materials -- to tell Lincoln's story. . . . The objects, artifacts and memorabilia . . . supplement the documents." What remained unexplored in the exhibition was the exact nature of this supplementary relationship, and how the audience's reception of both texts and objects might affect or stand in the way of ongoing critical examination of Lincoln's ideas. These questions raise several museological issues, all of which will be addressed in the course of this review. The Chicago Historical Society (CHS...
Collecting bird eggs is an established method of biomonitoring for specific pollution hazards. One of the most critical problems with this method is the extreme biological variability in bird eggs, but standardizing the collection and preservation of eggs can reduce these problems. Furthermore, standard practices are required so that the results can be compared among studies because mistakes cannot be corrected by laboratory analysis. Therefore, a standard procedure for collecting and preserving bird eggs may be necessary. The objective of this review is to investigate the current standard of quality assurance in the field by analyzing 86 peer-reviewed papers describing egg collection and use for aquatic birds. We show that little attention has been paid to standardizing how eggs are collected and stored in the field. Important information is often absent, including crucial aspects of sample collection and preservation, such as the freshness of the eggs, the position of the eggs in the laying sequence, the selection criteria, random sampling, and the duration and temperature of transport. Potential standards are suggested and discussed as a foundation for the development of quality assurance standards in the field.
In this study, residual concentration of organochlorine pesticides (OCPs) in the sediments, prey, and eggs of Bubulcus ibis were measured from three breeding heronries from the Punjab province of Pakistan. Pattern of contamination in eggs followed the order: DDTs > HCHs > heptachlor > aldrin. Overall, pesticide residual concentrations were greater in eggs of cattle egrets collected from heronry on the River Ravi. Among HCHs, γ-HCH was more prevalent in eggs, whereas DDTs followed the order: DDD > DDE > p,p ′-DDT > o,p ′-DDT. Eggshell thinning was detected which showed negative relationship with residual concentration of DDE. In prey samples, residual concentration of POPs followed the order: DDTs > HCHs > dicofol > heptachlor; however, contamination pattern in sediments followed a slightly different order: DDTs > heptachlor > dicofol > HCHs > dieldrin > aldrin. Concentration of β-HCH was more prevalent in sediments and comparatively greater concentrations of POPs were measured in sediments collected from the River Ravi. Dicofol was found for the very first time in the biological samples from Pakistan, and its concentration was measured as relatively high in eggs from heronry from the River Chenab. Residual concentrations measured in eggs were below the levels that could affect egret populations. Biomagnification of the total OCPs through the food chain was evident in three breeding heronries. The concentration of DDE measured in eggs of the cattle egret suggests the need for monitoring this contaminant in other bird species at different trophic levels.
Waterbirds are particularly subject to accumulation of persistent organic pollutants (POPs) that have been shown to constitute a major hazard for this group of birds. Liver and fat tissue from ten species belonging to the orders Ciconiformes (Ardeidae, Ciconiidae, Phoenicopteridae) and Pelicaniformes (Pelecanidae, Phalacrocoracidae) were used as bioindicators in order to assess environmental pollution by POPs (HCHs, DDTs, cyclodienes, PCBs) in Greek wetlands. To our knowledge, this is the first study on POPs in livers of water birds in Greece and Eastern Mediterranean area. The DDTs consisted mainly of p,p'-DDE with percentages over 60% in the great majority of the samples. The highest summation SigmaDDT concentrations were measured in the liver and subcutaneous fat of Phoenicopterus rubber and in Ardea purpurea liver (15565, 24706 and 10406 ng g(-1) wet weight, respectively). Low concentrations of cyclodienes (Cycls) and HCHs were detected occasionally and the contamination pattern of OCPs in most species of waterbirds followed the order summation SigmaDDTs> summation SigmaCycls> summation SigmaHCHs. Individual values of total PCBs reached the levels of 4468 and 3252 ng g(-1) wet weight, for Nycticorax nycticorax and Egretta garzetta samples respectively. Some of the recorded differences in organochlorine concentrations could be due to different causes of death, with a subsequent effect on body lipid levels. Organochlorine pesticides and PCBs residues were lower than those commonly associated with mortality and reduced reproductive success in most species. However, low level exposure to these contaminants may constitute one of the many stressors that in combination could adversely affect bird populations.
Environmental contaminants can have profound effects on birds, acting from the molecular through population levels of biological organization. An analysis of potential contaminant threats was undertaken at 52 Important Bird Areas (IBAs) within the northeastern Atlantic coast drainage. Using geographic information system methodology, data layers describing or integrating contamination (impaired waters, fish or wildlife consumption advisories, toxic release inventory sites, and estimates of pesticide use) were overlaid on buffered IBA boundaries, and the relative threat at each site was ranked. Some species of birds residing at Jefferson National Forrest (NF), Stewart B. McKinney National Wildlife Refuge (NWR), Great Dismal Swamp NWR, Blue Ridge Parkway, Shenandoah National Park (NP), Adirondack Park, Edwin B. Forsythe NWR, George Washington NF, Green Mountain NF, Long Island Piping Plover Beaches, and Merrymeeting Bay may be threatened by environmental contaminants. These sites exhibited moderate to high percentages of impaired waters and had fish consumption advisories related to mercury and polychlorinated biphenyls, and were located in counties with substantial pesticide use. Endangered, threatened, and Watch List bird species are present at these sites. The Contaminant Exposure and Effects-Terrestrial Vertebrates database was searched within buffered IBA boundaries, and for a moderate number of sites there was concordance between the perceived risk and contaminant exposure. Several of the IBAs with apparently substantial contaminant threats had no avian ecotoxicological data (e.g., George Washington NF, Shenandoah NP). Based upon this screening level risk assessment, contaminant biomonitoring of birds is warranted at such sites, and data generated from these efforts could foster natural resource management activities.
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We investigated wading bird productivity in four estuaries from Delaware Bay to Boston Harbor in northeastern U.S.A. over the period 1986-1998. To document and characterize reproductive performance of numerically dominant species for use in wildlife and habitat management planning, we recorded 1) number of eggs laid, 2) percent of eggs hatched, 3) percent of hatchlings surviving 10-15 days post-hatch, 4) number of nestlings produced, and 5) factors of offspring mortality in nests of Black-crowned Night Heron (Nycticorax nycticorax), Snowy Egret (Egretta thula), Cattle Egret (Bubulcus ibis), and Glossy Ibis (Plegadis falcinellus). We randomly selected 30-50 nests of each species (as available) for study at colonies in Delaware Bay (1993-1998), New York Harbor (1986-1994), Cape Cod (1990-94), and Boston Harbor (1993-94). In addition, we recorded abundance of nesting wading birds and avian predators in most years of study. Colony size ranged from 120-8,300 nests. Clutch size of all species was greater at northern-most sites. Loss of eggs varied between estuaries for all species except Glossy Ibis. Hatching success ranged from 75-88% and differed between estuaries for Black-crowned Night Heron and Glossy Ibis. Hatchling survival ranged from 16-87% and was lowest in Delaware Bay for all species. Nestling production was lowest in Delaware Bay for all species. In general, predation was high in Delaware Bay and egg inviability was high in Boston Harbor. Predation of nestlings was greatest in Delaware Bay for Cattle Egret, but there were no differences between estuaries for other species. Proportions of avian predators to nesting herons did not explain high predation rates in Delaware Bay.
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We studied reproductive characteristics of Black-crowned Night-Herons (Nycitcorax nycticorax) at 4 colonies in south central Washington and 1 colony in north central Oregon in 1991. Nest success, adjusted using the Mayfield method, was significantly different between colonies and ranged from 12-84% to hatching and 12-73% to 14 days post-hatching. The mean number of young surviving to 14 days of age in each colony ranged from 0.47-1.94 per nesting female (includes recycling efforts that involve laying more than 1 clutch). There were marked intercolony differences in clutch size and incidence of recycling. Predation (primarily avian) was a major factor that adversely affected nest success in 3 colonies and was relatively unimportant in 2 colonies. Residues of DDE, total polychlorinated biphenyls, 2,3,7,8-tetrachlorodibenzo-p-dioxin, and other compounds in eggs were generally low and apparently had little influence on reproductive success at any of the colonies. Mean eggshell thinning ranged from 7-11% in comparison to a pre-1947 norm for eggs measured in museum collections. Cytochrome P450 enzyme (EROD, PROD, and BROD) induction in livers of pipped embryos by colony ranged from low to average in comparison with other colonies throughout the U.S. Average EROD and BROD activities were highest at Sand Dune Island and were lowest at Potholes Reservoir which was designated the reference colony. In relation to our study of 3 of the 5 colonies in the early 1980s, residues of DDE and several related compounds appeared to decline, nest predation rates increased, and nest success decreased at all 3 colonies.
Cytochrome P450-associated monooxygenase activities and cytochrome P450 proteins were measured in pipping black-crowned night heron (Nycticorax nycticorax) embryos collected from a reference site (next to the Chincoteague National Wildlife Refuge, VA) and three polluted sites (Cat Island, Green Bay, Lake Michigan, WI; Bair Island, San Francisco Bay, CA; West Marin Island, San Francisco Bay, CA). In a laboratory study, artificially incubated night heron embryos from the reference site were treated with 3-methylcholanthrene or phenobarbital. Compared to controls, 3-methylcholanthrene induced a greater than fivefold increase in activities of several monooxygenases and a greater than 100-fold increase in the concentration of immunodetected cytochrome P450 1A (CYP1A). Phenobarbital treatment resulted in only a slight increase in BROD activity but induced proteins recognized by antibodies to cytochrome P450 2B (CYP2B) by 2,000-fold. In a field study, activities of AHH, BROD, EROD, and ethoxycoumarin-O-dealkylase (ECOD) were up to 85-fold higher in pipping black-crowned night herons collected from Cat Island compared to other sites. Hepatic CYP1A and CYP2B cross-reactive proteins were detected in significantly more individuals from Cat Island than from the reference site. Greatest burdens of total PCBs and p,p[prime]-DDE were detected in embryos from Cat Island. Cytochrome P450-associated monooxygenase activities and cytochrome P450 proteins (AHH, BROD, EROD, ECOD, CYP1A, CYP1B) were significantly associated with total PCB burdens.
Organochlorine contamination was studied in eight black-crowned night-heron (Nycticorax nycticorax) populations nesting in Washington, Oregon, and Nevada in 1978-80. DDE was detected in 220 eggs sampled; eggshell thickness was negatively correlated with residues of DDE and polychlorinated biphenyls (PCB's). Other contaminants were detected in 35% or fewer of the eggs. Except for the two Columbia River colonies in which local DDE contamination was a probable compounding factor, a strong north-south clinal pattern of DDE residues among colonies existed. Southern colonies were most contaminated, and observed productivity was below population maintenance in one colony (Ruby Lake). At DDE levels in eggs above 8 ppm, clutch size and productivity decreased, and the incidence of cracked eggs increased. No evidence of breeding-ground DDE-DDT contamination was found except along the Columbia River.
Less contaminated Nycticorax nycticorax from Oregon-Idaho wintered primarily in coastal Mexico (mean latitude 22-23oN), while the more contaminated Ruby Lake, Nevada night herons wintered in the SW USA with some in interior N Mexico (mean latitude 29-30oN). The nearly disjunct wintering areas for these populations, and the differing pollutant loads on the wintering areas, together accounted for the 3-fold higher DDE egg residues at Ruby Lake.-from Authors
Pipping black-crowned night-heron (Nycticorax nycticorax) embryos were collected from a relatively uncontaminated site (next to Chincoteague National Wildlife Refuge, VA) and three polluted sites (Cat Island, Green Bay, Lake Michigan, WI; Bair Island, San Francisco Bay, CA; West Marin Island, San Francisco Bay, CA). Hepatic cytochrome P450-associated monooxygenases and cytochrome P450 proteins, induced up to 85-fold relative to the reference site, were associated with concentrations of total polychlonrinated biphenyls (PCBs) and 11 PCB congeners that are presumed to express toxicity through the arylhydrocarbon (Ah) receptor Multiple regression revealed that up to 86% of the variation of cytochrome P450 measurements was accounted for by variation in the concentration of these PCB congeners. Toxic equivalents (TEQs) of sample extracts, predicted mathematically (summed product of PCB congener concentrations and toxic equivalency factors), and dioxin equivalents (TCDD-EQs), derived by bioassay (ethoxyresorufin-O-dealkylase activity of treated H4IIE rat hepatoma cells), were greatest in Cat Island samples. Cytochrome P450-associated monooxygenases and cytochrome P450 proteins were related to TEQs and TCDD-EQs; adjusted r2 often exceeded 0 5 for the relation among mathematically predicted TEQs and cytochrome P450 measurements. These data extend previous observations in heron embryos of an association between P450 and total PCB burdens to include Ah-active PCB congeners, and presumably other compounds, which interact similarly with the Ah receptor Benzyloxyresorufin O-dealkylase, ethoxyresorufin O-dealkylase, and cytochrome P450 1A appear to be the most reliable measures of exposure to Ah-active PCB congeners in black-crowned night-heron embryos. These findings provide further evidence that cytochrome P450-associated parameters have considerable value as a biomarker for assessing environmental contamination of wetlands