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The toxicokinetics of triphenyl phosphate (TPHP) in vivo including the uptake, deposition, and biotransformation into the metabolite diphenyl phosphate (DPHP) is presently reported in embryonated eggs and chicks of Japanese quail. Quail were dosed with TPHP at 3 concentrations by air cell egg injection on embryonic day 0, followed by daily oral dosing after chicks hatched (5 d). Vehicle-only exposed controls were also used. In dosed eggs, only 33% of the TPHP remained 2 d after injection (no hepatic development); after 10 d (post-hepatogenesis), only 2% remained. The estimated TPHP half-lives in the eggs ranged from 1.1 to 1.8 d for the 3 dosed groups. In all exposed eggs and chicks, DPHP significantly increased with dose (0.001 < p < 0.044). It appears that DPHP is an important metabolite in quail, making up 41 to 74% of all metabolites formed in embryonated eggs. In chicks, at medium and high doses, DPHP concentrations significantly exceeded those of TPHP (p ≤ 0.007), making up 67 and 76% of the total burden, respectively. Our findings suggest that rapid TPHP metabolism occurred in chicks and embryonated quail eggs but that this may vary with the age of the embryonated egg and the stage of embryo development, which should be considered when evaluating concentrations of TPHP and DPHP measured in eggs of wild birds. Environ Toxicol Chem 2020;39:565-573. © 2019 Her Majesty the Queen in Right of Canada. Environmental Toxicology and Chemistry © 2019 SETAC.

Mining in the Athabasca Oil Sands Region (AOSR) has contributed extensively to increased exposure of wildlife to naturally occurring polycyclic aromatic compounds (PACs), yet little is known about the toxicity of PACs to wildlife in this region. We identified reproductive and developmental changes in tree swallows (Tachycineta bicolor) breeding in close proximity to mining-related activities in the AOSR, and determined these changes in relation to the birds' exposure and accumulation of 41 PACs (parent-, alkylated-PAHs), dibenzothiophenes (DBTs; previously published), diet (carbon (δ13C), nitrogen (δ15N)), volatile organic compounds, and weather variables. Tree swallow pairs (N = 43) were compared among mining-related (OS1, OS2) and reference (REF1, REF2) sites. At OS2, clutch initiation was slightly advanced (2012) but reproductive success (65%) was much lower than at the other sites (≥ 79%). Fledgling production by each pair was influenced by the timing of clutch initiation (years combined); in a highly inclement brood rearing period (2013), additional influences included the nestlings' exposure to ΣDBTs, accumulation of C1-naphthalene, the trophic position of the prey in their diet (δ15N), and record-breaking rainfall. Nestlings at OS2 were significantly lighter at day (d) 9 and d14, and in poorer body condition (d9). Nestling body mass was influenced by multiple stressors that varied by site: mass of younger nestlings (d9) was related to dietary source (δ13C; e.g., wetlands, terrestrial fields), exposure and/or accumulation of C1-phenanthrenes, C2-fluorenes, Σalkyl-PAHs and ΣDBTs, while for older nestlings (d14), body mass was related to sex, hatch date and/or rainfall during brood rearing. The swallows' exposure and accumulation of parent-PACs, alkyl-PACs and DBTs, the timing of hatching, their diet and exposure to highly inclement rains, contributed to their reproductive and developmental changes.

Gulls (Larids) have become successful at exploiting anthropogenic areas for foraging. However, little is known on the health implications of using anthropogenic habitats and on the associated exposure to environmental contaminants, particularly with respect to plasma biochemistry that is routinely used to diagnose physiological disorders and diseases. The objective of the present study was to investigate the effects of anthropogenic habitat use and exposure to ubiquitous halogenated flame retardants (HFRs) on plasma biochemistry of urban-breeding ring-billed gulls (Larus delawarensis) from one of the largest colonies in North America. Miniature GPS dataloggers were used to characterize foraging habitat use of individual gulls (n = 39) at the regional scale (urban, waste management facilities, agricultural fields, and St. Lawrence River) in the Montreal area (QC, Canada), and plasma was analyzed for a suite of biochemical measures (waste products, lipids, glucose, ions, proteins, and enzymes) and HFRs. Several confounding biological and environmental variables were also assessed including sex, body condition, time spent fasting while incubating, plasma thyroid hormone levels, time of day, capture date, and ambient temperature. As ring-billed gulls (males and females combined) spent more time foraging in urban areas, their plasma concentrations of cholesterol, albumin and activity of alkaline phosphatase increased significantly. Moreover, as the gulls spent more time foraging in agricultural fields, their plasma concentrations of phosphorous and activity of aspartate aminotransferase increased significantly. Only the activity of aspartate aminotransferase was significantly positively related to plasma HFR concentrations (PBDEs and dechlorane-related compounds). Time spent fasting while incubating, plasma thyroid hormone levels, body condition, time of day, and capture date were significantly related to certain plasma biochemical measures. The present results suggest that both the use of anthropogenic habitats for foraging and exposure to HFRs may affect the plasma biochemistry of ring-billed gulls breeding in the densely-populated Montreal area, suggesting potential adverse health effects for avian wildlife living in highly urbanized environments. Keywords: Polybrominated diphenyl ethers, Dechlorane plus, Clinical chemistry, Urban birds, Habitat use

The current-use brominated flame retardant, 1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (DBE-DBCH), is capable of perturbing sex steroid and thyroid hormone pathways in vitro and in vivo. Chemicals with this capability may also disrupt metabolic processes and are candidate obesogens, but this potential has not yet been determined for DBE-DBCH. Our objective was to examine gross biomarkers of metabolic disruption in captive American kestrels. Birds were exposed by diet to the β isomer at the environmentally relevant dose of 0.239 ng β-DBE-DBCH/g kestrel/day, from 30 days (d) prior to pairing through until chicks hatched (82 d) (n = 30 breeding pairs) or for 28 d (n = 16 pre-breeding pairs), and were compared with vehicle-only exposed controls. Body mass was assessed throughout the breeding season at biologically relevant time points, flight and feeding behavior was measured in 5-min samples daily, and plasma triglycerides and cholesterol were assessed at d10 of brood rearing. Treated males were heavier than controls at pairing (p = 0.051), the final week of courtship (p = 0.061), and at d10 (p = 0.012) and d20 of brood rearing (p = 0.051); β-DBE-DBCH-exposed breeding females were similar in weight to control females. Treated birds tended to have higher plasma triglycerides (p = 0.078), which for females, was positively associated with body mass (p = 0.019). Heavier breeding males had higher plasma concentrations of testosterone and total thyroxine (p ≤ 0.046). Overall, both sexes exposed to β-DBE-DBCH demonstrated reduced flight behavior and increased feeding behavior during courtship. In the pre-breeding pairs, treated male and female kestrels had a higher percentage of body fat than respective controls (p = 0.045). These results demonstrate that β-DBE-DBCH elicited inappropriate fat and weight gain in adult American kestrels, consistent with their increased feeding, reduced flight activity and endocrine changes, and suggests that DBE-DBCH may be an obesogen warranting further research to test this hypothesis.

In the Canadian Athabasca Oil Sands Region (AOSR), nestling tree swallows (Tachycineta bicolor) raised near mining-related activities accumulated greater concentrations of polycyclic aromatic compounds (PACs) that contributed to their poorer condition, growth, and reproductive success. Here, we report changes in thyroid function of the same 14 day old (do) nestlings (N ≤ 68) at these mining-related sites (OS1, OS2) compared to reference nestlings (REF1), and in relation to multiple environmental stressors that influence avian thyroid function. Thyroid function was compromised for OS1 nestlings but generally comparable between OS2 and REF1 chicks. In 2012, circulating total triiodothyronine (TT3) and thyroxine (TT4) were similar among all nestlings. The OS1 chicks had more active thyroid glands based on histological endpoints. Hepatic T4 outer-ring deiodinase (T4-ORD) activity was suppressed in OS1 and OS2 chicks. Despite inter-annual differences, OS1 chicks continued experiencing compromised thyroid function with significantly higher circulating TT4 and more active thyroid glands in 2013. The OS2 chicks had less active thyroid glands, which conceivably contributed to their suppressed growth (previously reported) relative to the heavier OS1 nestlings with more active thyroid glands. Thyroid gland activity was more influenced by the chicks’ accumulation of (muscle), than exposure (feces) to naphthalene, C2-naphthalenes, and C1-fluorenes. Of four major volatile organic contaminants, sulfur dioxide (SO2) primarily influenced thyroid gland activity and structure, supporting previous findings with captive birds. When collectively considering environmental-thyroidal stressors, chicks had a greater thyroidal response when they experienced colder temperatures, accumulated more C2-naphthalenes, and consumed aquatic-emerging insects with higher PAC burdens than terrestrial insects (carbon (δ13C)). We hypothesize that the more active thyroid glands and higher circulating TT4 of the OS1 chicks supported their growth and survival despite having the highest PAC burdens, whereas the lack of thyroid response in the OS2 chicks combined with high PAC burdens, contributed to their smaller size, poorer condition and poorer survival.

Flame retardants (FR) are industrial chemicals and some are proven environmental contaminants that accumulate in predatory birds. Few studies have examined the influence of diet on FR profiles in nestling raptors and the possible physiological implications of such FR exposure. The objectives of this research were (1) to determine spatial patterns of ≤ 48 polybrominated diphenyl ether (PBDE) congeners and ≤ 26 non-PBDE FRs, including organophosphate esters (OPEs), in nestling peregrine falcons (Falco peregrinus) across the Canadian Great Lakes-St. Lawrence River Basin (GL-SLR; 2010) and in the eastern Canadian Arctic (2007); (2) to identify temporal changes in FR concentrations from the mid-2000s to 2010 in GL-SLR peregrine nestlings; (3) to investigate the role of diet using stable isotopes on exposure patterns of quantifiable FRs; and (4) to assess possible associations between circulating FRs and total (T) thyroxine (TT4) and triiodothyronine (TT3), tocopherol, retinol and oxidative status (isoprostanes). The summed concentrations of the top 5 PBDEs (Σ5) (BDE-47, -99, -100, -154, -153) were significantly higher in rural nestlings than urban nestlings in the GL-SLR, followed by the eastern Arctic nestlings. The PBDE congener profile of rural nestlings was dominated by BDE-99 (34‰), whereas BDE-209 (31‰) became dominant in the 2010 urban PBDE profile marking a shift since the mid-2000s. Low (ppb) concentrations of 25 novel non-PBDE FRs (e.g., 1,2-bis-(2,4,6-tribromophenoxy)ethane (BTBPE), decabromodiphenylethane (DBDPE)) were measured in the nestlings in at least one region, with the first report in peregrines of 15 novel non-PBDE FRs (e.g., 2-ethyl-1-hyxyl 2,3,4,5-tetrabromobenzoate (EHTBB), pentabromo allyl ether (PBPAE), tetrabromoethylcyclohexane (α-, β-DBE-DBCH)) as well as of tris (2-butoxyethyl) phosphate (TBOEP) (0–7.5 ng/g ww) > tris(2-chloroisopropyl) phosphate (TCIPP) (0.1–5.5 ng/g ww) > tris(2-chloroethyl) phosphate (TCEP) (0.02–2.0 ng/g ww) > tris(1,3-dichloro-2-propyl) phosphate (TDCIPP) (0–1.0 ng/g ww). Within the GL-SLR, the urban nestlings’ diet had significantly more terrestrial sources (greater δ13C values) than the broader, more aquatic-based diet of rural peregrines. Dietary source (δ13C) was significantly associated with concentrations of Σ5PBDE, BDE-209, EHTBB, and 2,2–4,4′,5,5′-hexabromobiphenyl (BB-153), with trophic level (δ15N) also positively associated with BDE-209 levels. Compared to urban nestlings, the rural nestlings had significantly lower circulating concentrations of thyroxine (TT4), triiodothyronine (TT3), a greater proportion of TT3 relative to TT4 (TT3:TT4), tocopherol and oxidative status (isoprostanes), but higher retinol levels; the most recalcitrant PBDE congener, BDE-153, in combination with low concentrations of some novel FRs, particularly octabromotrimethylphenyllindane (OBIND), may influence circulating thyroid hormones, especially TT4, and retinol levels of peregrine falcon nestlings. These associations of FR-endocrine-biochemical measures suggest possible exposure-related changes in these birds and further study is warranted.

Polybrominated diphenyl ethers (PBDE) are persistent environmental pollutants that have been detected in wildlife globally. American kestrels exposed to the commercial PBDE mixture DE-71 have previously demonstrated reduced reproductive success and behaviors during courtship and brood rearing; however, it remains unknown whether DE-71 affects incubation. During breeding, captive kestrels were exposed to the DE-71 mixture dissolved in safflower oil at two environmentally relevant concentrations (low: 283.5 ± 48.2, high: 1104.8 ± 124.5 ng/g wet weight [ww]) via diet for an average of 75 d. Unexpected low in ovo concentrations of hexabromocyclododecane (HBCD) were also detected (low: 3 ± 1 ng/g ww, high: 16 ± 3 ng/g ww). All comparisons are made to control pairs. Kestrel pairs in the low- and high-exposure groups experienced longer incubation periods with increasing exposure to ΣPBDE and some individual congeners. As incubation progressed, pairs exposed to DE-71 had significantly lower nest temperatures, which were on average 19% lower in low-exposure nests and 35% lower in high-exposure nests during late incubation. The DE-71 exposed pairs (low and high) also demonstrated significantly reduced incubation constancy (defined as percent of temperature readings above the maximum daily ambient temperature) during early incubation compared to controls. Nest temperatures (all pairs) and incubation constancy (high pairs) during early incubation (d 1-3) were significantly and positively associated with the proportion of eggs that hatched per pair. Higher incubation constancy and incubating nest temperatures in the low-exposure group were associated with markedly less egg weight loss by mid-incubation. These findings demonstrate that exposure to PBDE significantly affected kestrels during incubation, a critical period for embryonic development.

Daily energy expenditure (DEE) in animals is influenced by many factors although the impact of stressors remains largely unknown. The objective of this study was to determine how multiple physiological stressors (parasite infection and contaminant exposure) and natural challenges (energy-demanding activities and weather conditions) may affect DEE in nesting ring-billed gulls (Larus delawarensis) exposed to high concentrations of persistent organic contaminants (POPs). Physical activity, temperature, gastrointestinal parasitic worm abundance, relative spleen mass, plasma thyroid hormone levels and liver concentrations of POPs were determined; field metabolic rate (FMR) was used as a measure of DEE. For females, FMR was best explained by the percent of time spent in nest-site attendance and exposure to temperatures below their lower critical limit (65% of variation); 32% was also explained by relative spleen mass. In males, FMR was best explained by the number of hours spent in nest site attendance and either relative spleen mass or liver concentrations of tetra-brominated diphenyl ethers (tetra-BDEs) (55% of variation). Relative spleen mass, as an important factor relating to FMR, was best explained by models with a combination of parasite abundance (Diplostomum for females and Eucoleus for males) in a negative relationship, and liver POP concentrations (p,p'-DDE for females and tetra-BDEs for males) in a positive relationship (34%, 55% of variation for females and males, respectively). This study demonstrates that immune activity may be an important factor affecting energy expenditure in ring-billed gulls, and that contaminants and parasite abundance may have both a direct and/or indirect influence on FMR.

Feathers are useful for monitoring contaminants in wild birds and are increasingly used to determine persistent organic pollutants. However, few studies have been conducted on birds with known exposure levels. We aimed to determine how well nestling feather concentrations reflect in ovo exposure to hexabromocyclododecane (α-, β- and γ-HBCDD), and to determine if feather concentrations are related to physiological biomarkers. Captive kestrels (n = 11) were exposed in ovo to maternally transferred HBCDD-isomers at concentrations of 127, 12 and 2 ng/g wet weight of α-, β- and γ-HBCDD (measured in sibling eggs), respectively, and compared to controls (n = 6). Nestling growth was monitored at 5 d intervals and circulating thyroid hormone concentrations assessed at d 20. Tail feathers were collected prior to the first molt and analyzed for HBCDD isomers. The mean ΣHBCDD concentration in feathers was 2405 pg/g dry weight (in exposed birds) and α-, β- and γ-HBCDD made up 32%, 13%, and 55%, respectively of the ΣHBCDD concentrations. This isomer distribution deviated from the typical dominance of α-HBCDD reported in vertebrate samples. Exposed chicks had significantly higher feather concentrations of β- and γ-HBCDD compared with controls (p = 0.007 and p = 0.001 respectively), while α-HBCDD concentrations did not differ between the two groups. Feather concentrations of α-HBCDD were best explained by egg concentrations of β- or γ-HBCDD concentrations (wi = 0.50, 0.30 respectively), while feather concentrations of β- and γ-HBCDD were influenced by growth parameters (rectrix length: wi = 0.61; tibiotarsus length: wi = 0.28). These results suggest that feather α-HBCDD concentrations may reflect internal body burdens, whereas β- and γ-HBCDD may be subject to selective uptake. The α-HBCDD concentrations in the feathers were negatively associated with the ratio of plasma free triiodothyronine to free thyroxine (T3:T4; p = 0.020), demonstrating for the first time that feather concentrations may be used to model the effect of body burdens on physiological endpoints.

1,2-dibromo-4-(1,2-dibromoethyl)cyclohexane (DBE-DBCH - formerly TBECH) is an emerging brominated flame retardant (BFR) pollutant with androgen potentiating ability and other endocrine disrupting effects in birds and fish. The objectives of this study were to determine the effects of exposure to environmentally-relevant levels of DBE-DBCH on circulating levels of thyroid and sex steroid hormones in American kestrels, and if hormonal concentrations were related to previously reported changes in reproductive success and courtship behaviors. Sixteen kestrel pairs were exposed to 0.239ng β-DBE-DBCH/g kestrel/day by diet, based on concentrations in wild bird eggs, from 4 weeks before pairing until the chicks hatched (mean 82 d), and were compared with vehicle-only-exposed control pairs (n=15). As previously reported, DBE-DBCH concentrations were not detected in tissue or eggs of these birds, nor were any potential metabolites, despite the low method limits of detection (≤0.4ng/g wet weight), suggesting it may be rapidly metabolized and/or eliminated by the kestrels. Nevertheless, exposed kestrels demonstrated changes in reproduction and behavior, indicating an effect from exposure. During early breeding, males were sampled at multiple time points at pairing and during courtship and incubation; females were blood sampled at pairing only; both sexes were sampled at the end of the season. All comparisons are made to control males or control females, and the relative differences in hormone concentrations between treatment and control birds, calculated separately for each sex, are presented for each time point. Males exposed to β-DBE-DBCH demonstrated significantly (p=0.05) lower concentrations of total thyroxine (TT4) overall, that were 11-28% lower than those of control males at the individual sampling points, yet significantly higher (p=0.03) concentrations of free thyroxine (FT4), that were 5-13% higher than those of control males at the individual sampling points; females had similar concentrations of TT4 and FT4 at the time of pairing, and T4 was similar in both sexes at the end of the breeding season. Testosterone (T) concentrations in the treatment males were significantly higher during early (85%) and mid-courtship (30%) (time*treatment p=0.001), whereas females demonstrated a reduction in T at the time of pairing (17%, p=0.05). In the treatment females, concentrations of 17β-estradiol (E2) showed a non-significant decrease (20%) and were positively correlated with T concentrations (p=0.03); E2 concentrations were below quantification limits in males. For males, some variation in T was also significantly associated with their sexual behavior (p

Hexabromocyclododecane (HBCD) is a high production volume brominated flame retardant that has been detected in the environment and wildlife at increasing concentrations. This study was designed to determine potential effects of dietary exposure to environmentally relevant levels of HBCD on behavior during reproduction in captive American kestrels. Twenty kestrel pairs were exposed to 0.51 μg technical HBCD g −1 kestrel d −1 from 4 weeks prior to pairing until chicks hatched (∼75 d). Ten pairs of controls received the safflower oil vehicle only and were used for comparison. During the courtship period the chitter-calls were reduced in both sexes ( p = 0.038) and females performed fewer bonding displays ( p = 0.053). Both sexes showed a propensity to be less active than controls during courtship. The reduction in male courtship behavior was correlated with reduced courtship behaviors of females ( p ⩽ 0.008) as well as reduced egg mass ( p = 0.019). During incubation, nest temperatures of treatment pairs were lower at mid-incubation ( p = 0.038). HBCD-exposed males performed fewer key parental behaviors when rearing nestlings, including entering the nest-box, pair-bonding displays and food-retrievals. HBCD-exposed females appeared to compensate for the reduced parental behavior of their mates by performing these same behaviors more frequently than controls ( p = 0.004, p = 0.027, p = 0.025, respectively). This study demonstrates that HBCD affects breeding behavior in American kestrels throughout the reproductive season and behavioral alterations were linked to reproductive changes (egg size). This is the first study to report HBCD effects on reproductive behavior in any animal model.

Many species are adapted for fasting during parts of their life cycle. For species undergoing extreme fasts, lipid stores are mobilized and accumulated contaminants can be released to exert toxicological effects. However, it is unknown if short-term fasting events may have a similar effect. The objective of this study was to determine if short successive fasts are related to contaminant levels in liver and plasma of birds. In ring-billed gulls (Larus delawarensis), both members of the pair alternate between incubating the nest for several hours (during which they fast) and foraging, making them a useful model for examining this question. Birds were equipped with miniature data loggers recording time and GPS position for two days to determine the proportion and duration of time birds spent in these two activities. Liver and plasma samples were collected, and halogenated flame retardants (HFRs) (PBDEs and dechlorane plus) and organochlorines (OCs) (PCBs, DDTs, and chlordane-related compounds) were determined. Most birds (79%) exhibited plasma lipid content below 1%, indicating a likely fasted state, and plasma lipid percent declined with the number of hours spent at the nest site. The more time birds spent at their nest site, the higher were their plasma and liver concentrations of HFRs. However, body condition indices were unrelated to either the amount of time birds fasted at the nest site or contaminant levels, suggesting that lipid mobilization might not have been severe enough to affect overall body condition of birds and to explain the relationship between fasting and HFR concentrations. A similar relationship between fasting and OC levels was not observed, suggesting that different factors are affecting short-term temporal variations in concentrations of these two classes of contaminants. This study demonstrates that short fasts can be related to increased internal contaminant exposure in birds and that this may be a confounding factor in research and monitoring involving tissue concentrations of HFRs in wild birds. © 2015 Elsevier Inc.

High concentrations of polybrominated diphenyl ethers (PBDEs) accumulate in predatory birds. Several PBDE congeners are considered thyroid disruptors; however, avian studies are limited. The authors examined circulating thyroid hormones and thyroid gland function of nestling American kestrels (Falco sparverius) at 17 d to 20 d of age, following embryonic exposure by maternal transfer only to environmentally relevant levels of PBDEs (DE-71 technical mixture). Nestlings were exposed to in ovo sum (Σ) PBDE concentrations of 11 301 ± 95 ng/g wet weight (high exposure), 289 ± 33 ng/g wet weight (low exposure), or 3.0 ± 0.5 ng/g wet weight (controls, background exposure). Statistical comparisons are made to controls of the respective sexes and account for the relatedness of siblings within broods. Circulating concentrations of plasma total thyroxine (TT4 ) and total triiodothyronine (TT3 ) in female nestlings were significantly influenced overall by the exposure to DE-71. Following intramuscular administration of thyroid-stimulating hormone, the temporal response of the thyroid gland in producing and/or releasing TT4 was also significantly affected by the females' exposure to DE-71. The altered availability of T4 for conversion to T3 outside of the gland and/or changes in thyroid-related enzymatic activity may explain the lower TT3 concentrations (baseline, overall) and moderately altered temporal TT3 patterns (p = 0.06) of the treatment females. Controlling for the significant effect on TT3 levels of the delayed hatching of treatment females, baseline TT3 levels were significantly and positively correlated with body mass (10 d, 15 d, 20 d), with PBDE-exposed females generally being smaller and having lower TT3 concentrations. Given that exposure concentrations were environmentally relevant, similar thyroidal changes and associated thyroid-mediated processes relating to growth may also occur in wild female nestlings. Environ Toxicol Chem 2016;35:2084-2091. © 2016 SETAC.

Detected in environmental samples, 1,2-dibromo-4-(1,2-dibromoethyl) cyclohexane (DBE-DBCH) is a bioaccumulative isomer of a current-use brominated flame retardant. All 4 structural isomers are androgen agonists; however, little toxicological information exists for this compound. The objective of the present study was to determine if β-DBE-DBCH, the isomer found most prominently in animal tissue, affects androgen-dependent behavior of breeding American kestrels (Falco sparverius). The authors hypothesized that if β-DBE-DBCH acts as an androgen agonist in kestrels, androgen-dependent behaviors (i.e., copulation, courtship, aggression) would increase and behaviors inhibited by androgens (i.e., parental care behaviors) would decrease. Sixteen captive experimental kestrel pairs were exposed to 0.239 ng β-DBE-DBCH/g kestrel/d by diet from 4 wk prior to pairing until their nestlings hatched (mean 82 d) and compared with vehicle only-exposed control pairs (n = 15). Androgen-dependent behaviors were significantly increased in β-DBE-DBCH-exposed birds, consistent with the authors' hypothesis. These behavioral changes included copulation and other sexual behaviors in males and females and aggression in males, suggesting that β-DBE-DBCH may have acted like an androgen agonist in these birds. Parental behaviors were not reduced in exposed birds as predicted, although dietary exposure had ceased before chicks hatched. Further assessment of β-DBE-DBCH is recommended given these behavioral changes and the previously reported reproductive changes in the same birds.

Hexabromocyclododecane (HBCDD) is a flame retardant and a global contaminant, yet the toxicokinetics of HBCDD diastereoisomers remains unknown in wildlife species. The present study examined in captive American kestrels (Falco sparverius) (diastereo) isomer-specific HBCDD uptake, depletion, tissue distribution, and transfer to eggs in a dietary dosing study with an HBCDD technical mixture (HBCDD-TM). Adult tissue and plasma collections were from separate cohorts of unpaired individual males (n = 10) and females (n = 10) exposed for 21 d to 800 ng/g wet weight of HBCDD-TM (in safflower oil and injected into their cockerel [brain] diet), followed by a 25-d depuration period. A separate cohort of 12 males only was used for control adult tissue and plasma collections. For egg collections, separate cohorts of 11 control pairs (n = 22 birds) and 20 HBCDD-exposed pairs (n = 40 birds) were allowed to breed, and their eggs were collected (n = 19 exposed eggs and n = 10 control eggs). The sum (Σ) HBCDD concentrations were near or below detection (0.01-0.1 ng/g wet wt) in all control samples but quantifiable in all samples from exposed birds (no differences [p 0.05] between males and females). Arithmetic mean ΣHBCDD concentrations were highest in fateggsliverplasma. The mean ΣHBCDD depletion rate in plasma between the uptake and depuration periods was estimated to be 0.22 ng/g/d with a half-life of approximately 15 d. The γ-HBCDD diastereoisomer was60% of the ΣHBCDD in plasma after the uptake period and similar to the HBCDD-TM (∼80%). After the depuration period, α-HBCDD was70% of the HBCDD in plasma, fat, liver, and eggs; and this α-HBCDD domination indicated isomer-specific accumulation as a result of selective metabolism, uptake, protein binding, and/or in ovo transport.

Recently, the ban of hexabromocyclododecane (HBCD), a high-production-volume flame retardant, was announced in Europe and North America. However, the effects of HCBD remain understudied in birds. The objectives of the present comparative effects study were to determine whether exposure to an HBCD technical mixture (HBCD-TM) altered avian reproductive measures at an environmentally relevant concentration. American kestrels were exposed daily by food to HBCD-TM, i.e., 0.51 µg HBCD/g kestrel/d; exposed kestrels laid eggs that had α-HBCD concentrations (163.5 ± 75.1 ng/g wet wt) tenfold greater than β- and γ-HBCD isomers, an isomer profile and concentrations similar to those of eggs of wild peregrine falcons (Falco peregrinus). Concentrations of HBCD were not detected in the control kestrel eggs. In comparison with controls, the kestrels exposed to HBCD began to lay their eggs 6 d earlier and laid larger clutches of smaller eggs. The size of the eggs was inversely correlated with the in ovo α-HBCD concentrations. The smaller eggs of the HBCD exposed kestrels also lost more weight by midincubation, suggesting increased eggshell porosity since eggshell thickness was comparable. Generally birds that lay more eggs and lay earlier in the breeding season gain the advantage of better hatching and fledging success, yet the kestrels exposed to HBCD failed to have better reproductive success than the control birds. These reproductive changes were a function of HBCD exposure, likely through changes in food consumption, with possible impacts on, for example, reproductive behavior and/or alterations in thyroid hormones. Environ. Toxicol. Chem. 2011;30:2570–2575. © 2011 SETAC