Can predatory bird feathers be used as a non-destructive biomonitoring tool of organic pollutants?

Persistent organic pollutants in feathers of various terrestrial and aquatic bird species: Interspecies difference and source apportionment

Feathers are regarded as important nondestructive biomonitoring tools for bird pollutants. However, external contamination of feathers by different pollutants in different bird species remains unclear. In the present study, the feathers of 16 bird species, including terrestrial, freshwater, and marine birds, were analyzed for persistent organic pollutants (POPs). Bird feathers from an abandoned e-waste recycling site had higher POP concentrations and were more correlated with the POP muscle concentrations than those from the less polluted areas. The significant and positive POP correlations between the feathers and muscles of different species indicate that feathers are a good indicator of inter-species and spatial pollution. For individual species, the most hydrophobic POPs in feathers, such as hepta- to deca-polybrominated diphenyl ethers, had higher proportions than in muscles and worse correlations with muscle POPs compared with other POPs. Results of the chemical mass balance (CMB) model revealed that the gaseous phase, internal pollution, and atmospheric particle phase were the main contributors to low-, medium-, and high-hydrophobicity POPs in feathers, respectively. Overall, this study provides a preliminary but meaningful framework for distinguishing between internal and external contamination in feathers and gives information concerning the fitness of feathers as POP indicators with specific physicochemical properties.

Mercury and rare earth elements (REEs) show different spatial trends in feathers of Kentish plover (Charadrius alexandrinus) breeding along the Adriatic Sea coast, Italy

Feather analysis is an ethical and effective method for assessing the exposure of wild birds to environmental contamination due to trace elements and organic pollutants. We used feather to monitor the exposure to three toxic and non-essential metals (Hg, Cd, and Pb) and rare earth elements (REEs) of Kentish plover (Charadrius alexandrinus) breeding in different coastal areas (Veneto, Emilia-Romagna, Marche, Abruzzo, and Apulia) along the Italian coast of the Adriatic Sea. Feathers (n = 113) were collected from April to June. Feather concentrations evidenced a significant exposure to Hg (13.05 ± 1.71 mg kg-1 dw) and REEs (447.3 ± 52.8 ng g-1 dw) in the Kentish plover breeding in Veneto (n = 21) compared to the other coastal areas, with several individuals showing Hg concentrations above the adverse effect (5 mg kg-1 dw) and high-risk (9.14 mg kg-1 dw) thresholds reported for birds. Higher REE concentrations compared to Marche (n = 29), Abruzzo (n = 11) and Apulia (n = 13) were also reported for birds breeding in Emilia-Romagna (474.9 ± 41.9 ng g-1 dw; n = 29). The exposure to Cd and Pb was low in all the coastal areas, and only a few samples (n = 6 and n = 4 for Cd and Pb, respectively) exceeded the adverse effect thresholds (0.1 and 4 mg kg-1 for Cd and Pb, respectively). A significant sex-related difference was observed for REE-concentrations, with females showing higher concentration than males. These data highlight the need to monitor the exposure of the Kentish plover to Hg and REEs, especially in the northern basin of the Adriatic Sea, since these elements might negatively affect species' reproductive success and threaten its conservation.

Feather's Composition of South Polar Skua (Stercorarius maccormicki) Using WDXRF

This study investigated the feathers' composition of South polar skua (Stercorarius maccormicki) using WDXRF, evaluating the concentration of essential and non-essential elements in the feathers, and dividing it into rachis and barb parts. We collected South polar skuas feathers from Hennequin Point, King George Island, South Shetland, Antarctic Peninsula in January of 2013. Our results show that 18 elements were observed in the composition of the feathers, with a different concentration between the rachis and barbs, qualitatively and quantitatively. Only 3 elements observed were classified as non-essentials but still mostly elements do not have a function described in the literature to the feathers. According to our knowledge, this is the first study that uses this technique to evaluate the concentration of different elements in the feathers. The findings of this study highlight the use of alternative techniques to biomonitoring elements in the ecosystem and bring baseline information for future studies.

Assessing the trophic ecology and migration on the exposure of cape petrels and Wilson's storm petrels from Antarctica to perfluoroalkylated substances, trace and major elements

Chemical pollution is a global concern as contaminants are transported and reach even the remote regions of Antarctica. Seabirds serve as important sentinels of pollution due to their high trophic position and wide distribution. This study examines the influence of migration and trophic ecology on the exposure of two Antarctic seabirds, Wilson's storm petrel (Oceanites oceanicus - Ooc), and Cape petrel (Daption capense - Dca), to chemical elements and perfluoroalkyl substances (PFAS). Our methodology involved assessing the concentration of these pollutants in feather samples obtained from carcasses, offering a practical means for monitoring contamination. Trace and major element concentrations were comparable in both species, suggesting that migratory patterns have a minimal impact on exposure levels. However, Ooc had higher concentration of PFAS compared to Dca (mean, ng g-1dry weight, PFOA: Ooc:0.710, Dca:0.170; PFTrDA: Ooc:0.550, Dca:0.360, and PFTeDA: Ooc:1.01, Dca:0.190), indicating that migration to the more polluted Northern Hemisphere significantly affects PFAS exposure. Furthermore, while no strong associations were found between either trace elements or PFAS and the three stable isotopes (δ13C, δ15N, and δ34S), a negative association was observed between PFUnDA and δ15N, hinting at potential biodilution. The research concludes that the migratory patterns of these seabird species affect their PFAS exposure, underscoring the critical need for further exploration and understanding of these relationships to better inform conservation strategies.

Elimination of endocrine disrupting phenolic compounds via feathers and claws in seabirds moulting in the Baltic and Russian Arctic

This paper investigates the effectiveness of phenol derivatives removal from bird organisms via claws and remiges, and performs a preliminary assessment of the usefulness of these epidermal products for environmental biomonitoring and estimating bird exposure levels. Concentrations of bisphenol A (BPA) and alkylphenols: 4-tert-octylphenol (4-t-OP) and 4-nonylphenol (4-NP) were determined in claws and remiges of long-tailed ducks Clangula hyemalis and razorbills Alca torda, obtained during a by-catch in the winter period (2014-2016) in the Southern Baltic region. For razorbills, the Baltic is a permanent habitat, while long-tailed ducks are migratory and stay in the Southern Baltic only during the non-breeding season. Their remiges are replaced in the Arctic seas of Siberia. The removal of phenol derivatives, depending on the compound and the epidermal product, ranges from 12 % to 34 %. Among these compounds, in both bird species, the highest degree of elimination was observed for 4-NP in remiges (<0.1-656.0 ng^.g^-1 dw) as well as claws (<0.1-338.6 ng^.g^-1 dw). On the other hand, the least removed compound in both the long-tailed duck and the razorbill was 4-t-OP. The removal of phenol derivatives from claws in both bird species was at the same level. However, 4-NP concentrations were found to be statistically significantly higher in razorbill remiges compared to those of the long-tailed duck (p < 0.05). Comparison of concentrations in the remiges of the long-tailed duck and the razorbill, moulted in two different environments with different levels of pollution and distances from sources, indicated that the Baltic Sea is approximately 3 times more polluted with 4-NP than the marine areas of the Russian Arctic. This demonstrates the potential for the use of 4-NP and remiges as indicators of environmental pollution with phenol derivatives.

An Estimate of the Scale and Composition of the Hedgehog (Erinaceus europeaus) Rehabilitation Community in Britain and the Channel Islands

The conservation benefits of wildlife rehabilitation are equivocal, but could be substantial for formerly common species that are declining rapidly but are still commonly admitted to wildlife centres. We used a questionnaire survey to estimate the number of practitioners rehabilitating West European hedgehogs (Erinaceus europaeus) in Britain and the numbers entering hospitals/centres in one benchmark year (2016); practitioners were identified using an internet search and snowball sampling. Overall, 304 rehabilitators were identified: 148 supplied data on their structure, and 174 outlined the number of hedgehogs admitted in 2016. The former comprised 62.6% small (≤50 hedgehogs admitted year−1), 16.7% medium-sized (51−250 yr−1), and 20.7% large (>250 yr−1) hospitals; however, these accounted for 4.8%, 12.4%, and 82.8% of hedgehog admissions, respectively. Small hospitals were less likely to be registered as a charity, have paid staff, have a social media account, to record admissions electronically, or to conduct post-release monitoring. However, they were more likely to operate from their home address and to have been established for ≤5 years. Extrapolations indicate that this rehabilitation community admitted >40,000 hedgehogs in 2016, of which approximately 50% could have been released. These figures suggest that wildlife rehabilitation has potentially been an important factor in the dynamics of hedgehog populations in Britain in the last two decades.

Perfluoroalkylated compounds in the eggs and feathers of resident and migratory seabirds from the Antarctic Peninsula

In this study, we investigated factors that influence the differences in exposure of perfluoroalkyl acids (PFAAs) from eight species of Antarctic seabirds, including Pygoscelis penguins, Stercorarius maccormicki, and Macronectes giganteus. We analyzed the relationship between foraging ecology (based on δ¹³C, δ¹⁵N, and δ³⁴S values) and PFAAs accumulated in eggs and breast feathers. Ten out of 15 targeted PFAAs were detected in eggs compared to eight in feathers. Mean ∑PFAA concentrations in feathers ranged from 0.47 in P. antarcticus to 17.4 ng/g dry weight (dw) in S. maccormicki. In eggs, ∑PFAA concentrations ranged from 3.51 in P. adeliae to 117 ng/g dw in S. maccormicki. The highest concentrations of most PFAAs were found in trans-equatorial migrators such as S. maccormicki, probably due their high trophic position and higher concentrations of PFAAs in the Northern Hemisphere compared to the Southern Hemisphere. Based on stable isotopes correlations, our results suggest that the trophic position (δ¹⁵N) and the foraging area (δ¹³C and δ³⁴S) influence PFAAs concentrations in Antarctic seabirds. Our results point to the possibility that long-distance migratory birds may have as bio-vectors in the transport of pollutants, including PFCAs, in Antarctic environments, although this must be further confirmed in future studies using a mass balanced approach, such as extractable organofluorine (EOF).

Feathers as an integrated measure of organohalogen contamination, its dietary sources and corticosterone in nestlings of a terrestrial bird of prey, the northern Goshawk (Accipiter gentilis)

In this study, we evaluated the suitability of body feathers, preen oil and plasma for estimation of organohalogen compound (OHC) exposure in northern goshawk Accipiter gentilis nestlings (n = 37; 14 nests). In addition, body feathers received further examination concerning their potential to provide an integrated assessment of (1) OHC exposure, (2) its dietary sources (carbon sources and trophic position) and (3) adrenal gland response (corticosterone). While tetrabromobisphenol A was not detected in any sample, the presence of polychlorinated biphenyls, organochlorine pesticides, polybrominated diphenyl ethers and hexabromocyclododecane in body feathers (median: 23, 19, 1.6 and 3.5 ng g^-1 respectively), plasma (median: 7.5, 6.2, 0.50 and 1.0 ng g^-1 ww, respectively) and preen oil (median: 750, 600, 18 and 9.57 ng g^-1 ww, respectively) suggests analytical suitability for biomonitoring of major OHCs in the three matrices. Furthermore, strong and significant associations (0.20 ≤ R² ≤ 0.98; all P < 0.05) among the OHC concentrations in all three tissues showed that body feathers and preen oil reliably reflect circulating plasma OHC levels. Of the dietary proxies, δ¹³C (carbon source) was the most suitable predictor for variation in feather OHCs concentrations, while no significant relationships between body feather OHCs and δ¹⁵N (trophic position) were found. Finally, body feather corticosterone concentrations were not related to variation in OHC concentrations. This is the first study to evaluate feathers of a terrestrial bird of prey as an integrated non-destructive tool to jointly assess nestling ecophysiology and ecotoxicology.

Application and Evaluation of Novel Chromatographic Techniques to Detect and Quantitate 108 Pesticides and Metabolites in Muscle Samples From Wild Birds of Prey

The application and evaluation of highly efficient chromatographic techniques with tandem mass spectrometry for the detection and quantitation of 108 pesticides and metabolites, some considered persistent organic pollutants, was performed in muscle samples obtained from 25 birds of prey belonging to the families Accipitridae, Falconidae, and Strigidae presented dead in 2013 to Grupo de Rehabilitación de la Fauna Autóctona y su Hábitat, in Madrid, Spain. Pesticides with prohibited use were detected at high concentrations in the muscle samples analyzed. Based on its high sensitivity to detect pesticides in muscle, the described chromatographic techniques with tandem mass spectrometry should be considered an alternative testing methodology to those commonly used for routine application in ecotoxicological forensic research.

A review on contaminants of emerging concern in European raptors (2002-2020)

Raptors (birds of prey and owls) have been widely used as suitable bioindicators of environmental pollution. They occupy the highest trophic positions in their food chains and are documented to bioaccumulate high concentrations of persistent pollutants such as toxic metals and legacy persistent organic pollutants (POPs).Whereas raptors played a critical role in developing awareness of and policy for chemical pollution, they have thus far played a much smaller role in current research on contaminants of emerging concern (CECs). Given the critical knowledge obtained from monitoring 'legacy contaminants' in raptors, more information on the levels and effects of CECs on raptors is urgently needed. This study critically reviews studies on raptors from Europe reporting the occurrence of CECs with focus on the investigated species, the sampled matrices, and the bioanalytical methods applied. Based on this, we aimed to identify future needs for monitoring CECs in Europe. Perfluoroalkyl substances (PFASs), novel flame retardants (NFRs), and to a lesser extent UV-filters, neonicotinoids, chlorinated paraffins, parabens and bisphenols have been reported in European raptors. White-tailed Eagle (Haliaeetus albicilla), Peregrine falcon (Falco peregrinus) and Northern goshawk (Accipiter gentilis) were the most frequently studied raptor species. Among matrices, eggs, feathers and plasma were the most widely employed, although the potential role of the preen gland as an excretory organ for CECs has recently been proposed. This review highlights the following research priorities for pollution research on raptors in Europe: 1) studies covering all the main classes of CECs; 2) research in other European regions (mainly East Europe); 3) identification of the most suitable matrices and species for the analysis of different CECs; and 4) the application of alternative sample treatment strategies (e.g. QuEChERS or pressurized liquid extraction) is still limited and conventional solvent-extraction is the preferred choice.

Non-invasive biomonitoring of organic pollutants using feather samples in feral pigeons (Columba livia domestica)

A large portion of organic pollutants (OPs) represent a potential hazard to humans and living beings due to their toxic properties. For several years, birds have been used as biomonitor species of environmental pollution. Polychlorinated biphenyls (PCBs), organochlorine pesticides (OCPs), polybrominated biphenyl ethers (PBDEs), organophosphate pesticides (OPPs), polycyclic aromatic hydrocarbons (PAHs) and pyrethroids (PYRs) were assessed in body feather samples of 71 feral pigeons (Columba livia domestica) collected from Asturias and Galicia (NW Spain). The percentage of detection for all chemical groups were above 90% in studied birds. The general pattern was dominated by PAHs (mean value ± standard deviation (SD) 32 ± 15 ng/g) followed by OCPs (3.8 ± 1.1 ng/g), PYRs (3.4 ± 3.8 ng/g), PCBs (1.6 ± 1.0 ng/g), OPPs (1.3 ± 0.70 ng/g) and PBDEs (0.80 ± 0.30 ng/g). Significant differences were observed between age, location and gender suggesting different sources of exposure and accumulation pathways.

Effects of urban proximity and the occurrence of erythroplastids in Antilophia galeata

Air pollution can generate changes in the morphology, physiology, and behavior of several animals, including birds, which, when responding to such environmental changes, can be used as biomonitors. Quantitative and qualitative analyses of erythrocyte nuclear anomalies comprise a useful tool for biomonitoring, with anucleated erythrocytes, called erythroplastids, being particularly significant. The objectives of the present study were to quantify the presence of erythroplastids in Antilophia galeata and relate their presence to distance from the nearest urban environment. Blood smears were analyzed for 80 individuals of A. galeata captured between June 2013 and October 2018 in five Cerrado forest fragments of different sizes and with different influences from urbanization. The quantity of erythroplastids differed among areas, with it being greater in fragments within a proximity with urban, and less in highly preserved areas far from an urban environment. Quantification of erythroplastids in A. galeata proved to be a useful tool for monitoring air quality.

Evidence of continued exposure to legacy persistent organic pollutants in threatened migratory common terns nesting in the Great Lakes

Persistent organic pollutants (POPs) accumulate in the food web of the Great Lakes ecosystem, causing concern that these chemicals play a role in the decline of avian species such as colonial-nesting waterbirds. In this study, samples from four life stages of the common tern (Sterna hirundo), a threatened species in New York State, were collected post-mortem in the Buffalo-Niagara region (United States). Brains (n = 26) and livers (n =27) were analyzed for polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), and the insecticide p,p'-dichlorodiphenyltrichloroethane (DDT) and its two metabolites p,p'-dichlorodiphenyldichloroethylene (DDE) and p,p'-dichlorodiphenyldichloroethane (DDD). Detectable concentrations of PCBs and PBDEs were observed in all samples; concentrations of total PCBs ranged from 5.59 to 2,490 ng/g wet weight (ww), total PBDEs ranged from 1.09 to 494 ng/g ww, and DDE metabolites ranged from 0.56 to 637 ng/g ww. Analysis of the primary food source for terns in the Buffalo-Niagara region, emerald shiners (Notropis atherinoides), revealed that all three classes of POPs had similar contaminant profiles in the fish to those in the brains and livers of tern samples. Overall, small chicks contained greater concentrations of pollutants than medium chicks and juveniles, likely from maternal loading to eggs. These results underline the persistence of these legacy contaminants in the Great Lakes, despite their banning, and their biomagnification in threatened species through food web interactions.

Are Feathers of a Songbird Model Species (The Great Tit, Parus major) Suitable for Monitoring Perfluoroalkyl Acids (PFAAs) in Blood Plasma?

Feathers have been shown to be useful in the biomonitoring of environmental contaminants, such as metals and persistent organic pollutants. However, little is known regarding the levels of perfluoroalkyl acids (PFAAs) in feathers and the applicability of these structures for the biomonitoring of these compounds. In the present study, we report the extent to which feathers are suitable for monitoring PFAA concentrations in the blood plasma of an insectivorous songbird model species, the great tit (Parus major), settled at and in the vicinity of a fluorochemical plant in Antwerp, Belgium. For most of the target analytes (out of the 15 investigated), the feather PFAA concentrations near the plant are the highest ever reported in free-living birds. As PFAA concentrations did not differ in the adjacent sites, no pollution gradient with distance from the plant was observed. In addition, the PFAA concentrations were not associated with the age and sex of the birds. Perfluorooctanoic acid (PFOA) concentrations were significantly higher in P. major feathers than in blood plasma, but for most other PFAAs, these differences were not observed. The concentrations of perfluorooctanesulfonate (PFOS) and PFOA in P. major feathers and plasma were significantly and positively correlated when combining data from all sites but often not at individual sites. This result was likely caused by lower sample sizes at the individual sites and the use of matrices that represent different time periods. Our results suggest that P. major feathers cannot be used to estimate PFOA and PFOS concentrations in blood plasma, except when there is a great deal of variation in pollutant concentrations among sites/individual birds. Both matrices represent different time frames, providing complementary information on environmental PFAA concentrations, as illustrated by the observation that more PFAA compounds could be detected in P. major feathers than in blood plasma.

Temporal trends of legacy organochlorines in different white-tailed eagle (Haliaeetus albicilla) subpopulations: A retrospective investigation using archived feathers

Understanding the spatiotemporal patterns of legacy organochlorines (OCs) is often difficult because monitoring practices differ among studies, fragmented study periods, and unaccounted confounding by ecological variables. We therefore reconstructed long-term (1939-2015) and large-scale (West Greenland, Norway, and central Sweden) trends of major legacy OCs using white-tailed eagle (Haliaeetus albicilla) body feathers, to understand the exposure dynamics in regions with different contamination sources and concentrations, as well as the effectiveness of legislations. We included dietary proxies (δ¹³C and δ¹⁵N) in temporal trend models to control for potential dietary plasticity. Consistent with the hypothesised high local pollution sources, levels of polychlorinated biphenyls (PCBs), dichlorodiphenyltrichloroethanes (DDTs) and hexachlorocyclohexanes (HCHs) in the Swedish subpopulation exceeded those in the other subpopulations. In contrast, chlordanes (CHLs) and hexachlorobenzene (HCB) showed higher concentrations in Greenland, suggesting the importance of long-range transport. The models showed significantly decreasing trends for all OCs in Sweden in 1968-2011 except for CHLs, which only decreased since the 1980s. Nevertheless, median concentrations of DDTs and PCBs remained elevated in the Swedish subpopulation throughout the 1970s, suggesting that the decreases only commenced after the implementation of regulations during the 1970s. We observed significant trends of increasing concentrations of PCBs, CHLs and HCB in Norway from the 1930s to the 1970s/1980s and decreasing concentrations thereafter. All OC concentrations, except those of PCBs were generally significantly decreasing in the Greenland subpopulation in 1985-2013. All three subpopulations showed generally increasing proportions of the more persistent compounds (CB 153, p.p'-DDE and β-HCH) and decreasing proportions of the less persistent ones (CB 52, p.p'-DDT, α- and γ-HCH). Declining trends of OC concentrations may imply the decreasing influence of legacy OCs in these subpopulations. Finally, our results demonstrate the usefulness of archived museum feathers in retrospective monitoring of spatiotemporal trends of legacy OCs using birds of prey as sentinels.

A screening of select toxic and essential elements and persistent organic pollutants in the fur of Svalbard reindeer

Reindeers play an important role in the polar ecosystem, being long-lived sole vegetarians feeding on local vegetation. They can be used as a valuable bioindicator, helping us to understand contaminants' impact on the polar terrestrial ecosystem. Still, scarce data exist from research in which polar herbivores (especially those from the European parts of the Arctic) were a major study subject for trace elements and persistent organic pollutant determination. Here, Svalbard reindeer fur has been used to determine metals, non-metals and metalloids using ICP-MS, and several persistent organic pollutants including polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs) using gas chromatography coupled to a tandem mass spectrometer (GC-MS/MS). Samples were collected from reindeer populations living in the area near Ny-Ålesund and Longyearbyen. Essential elements like Fe, Mg, Zn, K, Ca, Cu predominated in the trace elements profile. Median values of As, Cd, Co, Li, Ni, Se and V were all below 0.5 μg/g dw. Mercury was below detection limit in all samples, while the Pb median varied from 0.35 to 0.74 μg/g dw. Except acenaphthylene and fluorene, PAHs were detectable only in samples collected in the vicinity of Longyearbyen. Of 15 studied pesticides, only DDT and its metabolites were above the detection limit, and, of PCBs, only PCB28.

Organochlorine pesticides in feathers of three raptor species in southern Brazil

In this study, we determined the presence of organochlorine pesticides (OCPs) in back feathers from three raptor species, Phalcoboenus chimango, Milvago chimachima and Caracara plancus. Samples were obtained from live animals and ten OCPs were detected: α-HCH, β-HCH and γ-HCH (lindane), heptachlor, heptachlor epoxide, aldrin, endosulfan I, endosulfan II, endosulfan sulfate and p,p'-DDE. The concentrations found were higher than those reported in other raptor species, and C. plancus showed greater values than P. chimango and M. chimachima for all the substances. These differences may be justified by the species feeding habits and the characteristics of the sampling area, since C. plancus were sampled in an area with a higher concentration of agricultural crops and urbanized environments. In relation to the possible negative effects, four individuals of C. plancus presented DDE values related to sublethal effects for other species. This is the first study reporting OCPs in back feathers of these species in Brazil, and further studies evaluating OCP exposure and related effects are important for a better understanding of the consequences of different OCP concentrations on the health of these species.

Accumulation of trace elements in feathers of the Kentish plover Charadrius alexandrinus

A non-invasive study of trace element accumulation in tail feathers of the Kentish plover (Charadrius alexandrinus) was performed along the coastline of the northern littoral strip of the Venice Lagoon, with the aim to verify whether contamination may be a factor affecting conservation status of Kentish plover populations. Body burdens in feathers of 11 trace elements including toxic metals/metalloids and essential elements (As, Cd, Co, Cr, Cu, Hg, Ni, Pb, Se, V, Zn) were quantified by ICP-MS, then concentrations were normalized to feather's age calculated using ptilochronology in order to obtain daily deposition rates. Mercury emerged as a major threat to the conservation of the species, since average feather concentration was clearly above the adverse-effect threshold associated with impairment in the reproductive success in a number of bird species. Also Cd and Se occurred at levels that may impact on the conservation status of the studied species at local scale, even if to a lesser extent than Hg. Gender-related differences in trace element accumulation emerged only for As, although for this element the risks associated to environmental exposure seem to be negligible.

Can variability in corticosterone levels be related to POPs and OPEs in feathers from nestling cinereous vultures (Aegypius monachus)?

Persistent organic pollutants (POPs) are still globally distributed and some have been shown to interact with the endocrine system of birds. However, the relationship between POPs and the stress response mediated by the hypothalamic-pituitary-adrenal (HPA) axis is still poorly understood. Raising concerns are now focused on the toxic properties of emergent organophosphate ester flame retardants (OPEs), but whether OPEs interact with the HPA axis response has not yet been investigated. We measured corticosterone concentrations in feathers (CORTf) as a long-term biomarker of the bird HPA axis response and we investigated their relationship with POP and OPE concentrations in down feathers of nestling cinereous vultures (Aegypius monachus). We also examined whether high contaminant burden and high CORTf concentrations impacted the duration of chick development. The most predominant compounds were the following: p,p'-DDE (3.28 ± 0.26 ng g^-1 dw) > γ-HCH (0.78 ± 0.09 ng g^-1 dw) > BDE-99 (0.73 ± 0.09 ng g^-1 dw) > CB-153 (0.67 ± 0.04 ng g^-1 dw). The most persistent POP compounds (CB-170, -177, -180, -183, -187, -194 and p,p'-DDE) were associated (P = 0.02) with high concentrations of CORTf (range: 0.55-6.09 pg mm^-1), while no relationship was found when OPEs were tested (P > 0.05). Later egg-laying was positively associated to high levels of CORTf (P = 0.02) and reduced duration of chick development (P < 0.001), suggesting a beneficial effect of the HPA axis response on the growth of the chicks. In addition, males with high concentrations of the most persistent POP compounds tended to show a reduced duration of the nestling period (P = 0.05) and an equal fledging success than chicks with lower levels. These findings suggest that POPs, but not OPEs, may interact with the HPA axis response of chicks, although levels were not high enough to cause detrimental consequences.

White-tailed eagle (Haliaeetus albicilla) feathers from Norway are suitable for monitoring of legacy, but not emerging contaminants

While feathers have been successfully validated for monitoring of internal concentrations of heavy metals and legacy persistent organic pollutants (POPs), less is known about their suitability for monitoring of emerging contaminants (ECs). Our study presents a broad investigation of both legacy POPs and ECs in non-destructive matrices from a bird of prey. Plasma and feathers were sampled in 2015 and 2016 from 70 whitetailed eagle (Haliaeetus albicilla) nestlings from two archipelagos in Norway. Preen oil was also sampled in 2016. Samples were analysed for POPs (polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorinated pesticides (OCPs)) and ECs (per- and polyfluoroalkyl substances (PFASs), dechlorane plus (DPs), phosphate and novel brominated flame retardants (PFRs and NBFRs)). A total of nine PCBs, three OCPs, one PBDE and one PFAS were detected in over 50% of the plasma and feather samples within each sampling year and location. Significant and positive correlations were found between plasma, feathers and preen oil concentrations of legacy POPs and confirm the findings of previous research on the usefulness of these matrices for non-destructive monitoring. In contrast, the suitability of feathers for ECs seems to be limited. Detection frequencies (DF) of PFASs were higher in plasma (mean DF: 78%) than in feathers (mean DF: 38%). Only perfluoroundecanoic acid could be quantified in over 50% of both plasma and feather samples, yet their correlation was poor and not significant. The detection frequencies of PFRs, NBFRs and DPs were very low in plasma (mean DF: 1-13%), compared to feathers (mean DF: 10-57%). This may suggest external atmospheric deposition, rapid internal biotransformation or excretion of these compounds. Accordingly, we suggest prioritising plasma for PFASs analyses, while the sources of PFRs, NBFRs and DPs in feathers and plasma need further investigation.

Influence of persistent organic pollutants on the endocrine stress response in free-living and captive red kites (Milvus milvus)

Persistent organic pollutants (POPs) have the potential to impair the endocrine regulation of organisms and alter their ability to respond to environmental changes. We studied whether polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) affected the endocrine regulation of free-living and captive red kites (Milvus milvus) through studying the dynamics of corticosterone (CORT) and dehydroepiandrosterone (DHEA). We sampled migratory free-living kites coming from northern Europe and captive kites born in a rehabilitation center in Spain. We used body feathers from the interscapular region as a minimally-invasive and integrative matrix. The most abundant compound detected in free-living kites was 4,4'-dichlorodiphenyldichloroethylene (4,4'-DDE; 6.10 ± 1.56 ng g^-1 dw feather) followed by CB-153 (3.10 ± 0.63 ng g^-1 dw feather) and CB-180 (2.43 ± 1.08 ng g^-1 dw feather). In captive kites, the most abundant compounds were 4,4'-dichlorodyphenyltrichloroethane (4,4'-DDT; 2.38 ± 1.30 ng g^-1 dw feather), CB-153 (2.15 ± 0.47 ng g^-1 dw feather) and hexachlorobenzene (HCB; 2.03 ± 0.45 ng g^-1 dw feather) at similar concentrations. Free-living kites showed higher levels of 4,4'-DDE and CB-180 in comparison to captive kites. Age influenced HCB and CB-101 levels, whereas body mass was inversely related to CB-180 and 4,4'-DDT. Interestingly, captive kites showed a ratio DDT/DDE higher than 1 suggesting a relatively recent exposure of DDT, in contrast to free-living kites. Regarding hormonal levels, free-living kites showed higher levels of CORT (3.30 ± 0.22 pg mm^-1 feather) than captive (2.40 ± 0.16 pg mm^-1 feather), reflecting higher allostatic load. In addition, a positive association between PCBs and DDTs and adrenal hormones was found in free-living kites, suggesting an increase of CORT as a response of the endocrine system to cope with stressors and a subsequent elevation of DHEA to ameliorate the potential negative effects that high CORT levels could cause to the organism.

First evaluation of the use of down feathers for monitoring persistent organic pollutants and organophosphate ester flame retardants: A pilot study using nestlings of the endangered cinereous vulture (Aegypius monachus)

Raptor feathers have been increasingly used to assess pollutants in ecotoxicological monitoring studies. However, the suitability of down feathers to detect pollutants has not yet been investigated. In this study, concentrations of persistent organic pollutants (POPs) and organophosphate ester flame retardants (OPEs) were assessed in down and juvenile contour feathers of Spanish cinereous vulture (Aegypius monachus) nestlings (circa 73 days old) and contaminant concentrations were compared between both types of feathers from the same individuals. Concentrations of polychlorinated biphenyls (PCBs: 1.30-6.16 ng g^-1 dw feather), polybrominated diphenyl ethers (PBDEs: 0.23-1.35 ng g^-1 dw feather), p,p'-dichlorodiphenyldichloroethylene (pp-DDE: 0.09-6.10 ng g^-1 dw feather) and tris (1-chloro-2-propyl) phosphate (TCiPP: 0.86-48.96 ng g^-1 dw feather) were significantly higher in down than in contour feathers. In contrast, contour feathers showed higher levels of the more volatile POP, lindane (0.25-3.12 ng g^-1 dw feather). Concentrations of hexachlorobenzene (HCB) and OPEs (except TCiPP) were similar between the two types of feathers. By showing high accumulation of the most persistent POPs investigated, down feathers presented a contamination profile similar to that previously described in raptor eggs. As these feathers grow during the first days of a vulture chicks life, they probably reflect the contaminant burden of the chick due to maternal transfer to the egg. Overall, the present study provides the first indication that down feathers may be useful for biomonitoring studies. Further research is needed to confirm whether nestling down feathers reflect the concentrations in the egg.

Persistent organic pollutants and organophosphate esters in feathers and blood plasma of adult kittiwakes (Rissa tridactyla) from Svalbard - associations with body condition and thyroid hormones

Polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), organochlorine pesticides (OCPs) and organophosphate esters (OPEs) were assessed in blood plasma and feathers of 19 adult black-legged kittiwakes (Rissa tridactyla) breeding in two colonies (Blomstrandhalvøya and Krykkjefjellet) at the Arctic archipelago, Svalbard. Potential associations with body condition index (BCI) and thyroid hormones were investigated. All compound classes were detected in both blood plasma and feathers, but due to low sample size and volumes, OPEs could only be quantified in four individuals, warranting larger follow-up studies. Kittiwakes breeding at Blomstrandhalvøya had significantly higher concentrations of organic pollutants in blood plasma than kittiwakes breeding at Krykkjefjellet (p < 0.001). Concentrations in blood plasma and feathers did not significantly correlate for any of the investigated compounds, and feather concentrations did not differ significantly between the colonies. This suggests that pollutant levels in adult kittiwake feathers do not reflect local contamination at breeding sites and are as such not useful to monitor local contamination at Svalbard. Significant negative associations between BCI and most pollutants were found in both populations, whereas significant correlations between the BCI, the ratio of total triiodothyronine to free triiodothyronine (TT3:fT3), and several pollutants were only found for kittiwakes from Blomstrandhalvøya (all r ≥ -0.60 and p ≤ 0.05). This indicates that higher levels of circulating pollutants during the breeding period covary with the TT3: fT3 ratio, and may act as an additional stressor during this period.

Contrasting congener profiles for persistent organic pollutants and PAH monitoring in European storm petrels (Hydrobates pelagicus) breeding in Ireland: a preen oil versus feathers approach

Persistent organic pollutants (POPs) and polycyclic aromatic hydrocarbons (PAHs) are anthropogenic contaminants of environmental concern due to their persistence in the environment and capacity to accumulate in biota. Many of these contaminants have been found to have ill effects over wildlife and humans. Birds are known to be particularly affected through endocrine disruption and eggshell thinning. POPs have been banned or restricted through the Stockholm Convention (2001), making monitoring essential for tracking effects of regulation. Seabirds have been used as monitoring tools for being top predators and consuming a diverse array of prey in different trophic levels. Non-destructive sampling has become widely popular using feathers and preen oil, as opposed to carcasses and internal organs. This study aimed to set baseline levels of POP and PAH concentration in a highly pelagic and abundant seabird in Ireland and the Atlantic, the European storm petrel, Hydrobates pelagicus, and to investigate the profiles of contaminant congeners in preen oil and feathers, comparatively. Mean concentrations in preen oil followed: PCB (10.1 ng/g ww) > PAH (7.1 ng/g ww) > OCP (5.4 ng/g ww) > PBDE (3.9 ng/g ww), whilst mean concentrations in feathers followed the order: PAH (38.9 ng/g ww) > PCB (27.2 ng/g ww) > OCP (17.9 ng/g ww) > PBDE (4.5 ng/g ww). Congener profiles highly differed between preen oil and feathers, and little correlation was found between the matrices. These results demonstrate that the sampling of a single matrix alone (preen oil or feathers) might produce confounding results on contamination in seabirds and that more than one matrix is recommended to obtain a full picture of contamination by persistent organic pollutants.

Conservation and the 4 Rs, which are rescue, rehabilitation, release, and research

Vertebrate animals can be injured or threatened with injury through human activities, thus warranting their "rescue." Details of wildlife rescue, rehabilitation, release, and associated research (our 4 Rs) are often recorded in large databases, resulting in a wealth of available information. This information has huge research potential and can contribute to understanding of animal biology, anthropogenic impacts on wildlife, and species conservation. However, such databases have been little used, few studies have evaluated factors influencing success of rehabilitation and/or release, recommended actions to conserve threatened species have rarely arisen, and direct benefits for species conservation are yet to be demonstrated. We therefore recommend that additional research be based on data from rescue, rehabilitation, and release of animals that is broader in scope than previous research and would have community support.

Retrospective biomonitoring of mercury and other elements in museum feathers of common kestrel Falco tinnunculus using instrumental neutron activation analysis (INAA)

This study examines the potential to use instrumental neutron activation analysis (INAA) to explore temporal and geographical variation in exposure to heavy metals and other selected elements in common kestrel Falco tinnunculus using feathers from a natural history collection. The study gathered samples of two breast feathers from each of 16 adult male kestrel specimens from Naturalis Biodiversity Centre, collected in The Netherlands between 1901 and 2001. Feather samples were analysed for more than 50 elements, using INAA at the Reactor Institute Delft. Results (in mg/kg dw) were transformed into ratios of milligram of element per millimetre of feather length. The distribution of the mass fractions and ratios was plotted for each element against time and by geographical area. Observed mass fractions and/or ratios are discussed for selected elements (Hg, Cd, Zn, Pt, Pd, Se, Al, Rb, As, Sb, Cr, V, Cl, Br) known to have, at certain concentrations, adverse effects on raptors. Some samples show mass fractions of certain elements (Cr, Cd, Se, As) above levels known to have adverse effects. We conclude that the analysis of museum feathers using INAA provides reference values for concentrations of selected elements, including those of high societal concern such as Hg and Cd, against which to assess concentrations of these elements in feathers of present-day living raptor populations.

Presence of persistent organic pollutants in a breeding common tern (Sterna hirundo) population in Ireland

Persistent organic pollutants (POPs) are chemical compounds of environmental concern due to their toxic, persistent nature and their ability to bio-accumulate in biological tissue. Seabirds, for often being at the top of the food web, have been used as monitors of environmental pollutants. Adverse effects caused by POPs have been reported in common terns (Sterna hirundo) since the 1970s. Egg shell thinning, embryo and hatchling deformities have been reported for this species. Environmental legislation, such as the Oslo-Paris Convention (OSPAR), has agreed on the monitoring of concentration of POPs in common terns. This study set out to investigate contemporary concentrations of polychlorinated biphenyls (PCBs), polycyclic aromatic hydrocarbons (PAHs), organochlorine pesticides (OCPs) and brominated flame retardants (BFRs) in common terns breeding in Ireland, along with congener profiles. Investigation was conducted in live (n = 15) and dead birds (n = 20) to test for the efficiency of different methodologies using preen oil and feathers versus liver and preen gland. Mean concentrations of POPs followed the order: PCB (36.48 ng/g ww feather) > PAH (30.01 ng/g ww feather) > OCP (13.36 ng/g ww feather) > BFR (1.98 ng/g ww feather) in live birds; and PAH (46.65 ng/g ww preen gland) > PCB (44.11 ng/g ww preen gland) > OCP (15.15 ng/g ww liver) > BFR (5.07 ng/g ww liver) in dead birds. Comparison of contaminant results with toxicity pre-established levels concluded that this population of common terns in Ireland is not at risk of anomalies caused by POPs. However, some levels are higher in comparison to the ones established by OSPAR's EcoQO and must be monitored periodically.

Transfer of hexabromocyclododecane flame retardant isomers from captive American kestrel eggs to feathers and their association with thyroid hormones and growth

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 (w_i = 0.50, 0.30 respectively), while feather concentrations of β- and γ-HBCDD were influenced by growth parameters (rectrix length: w_i = 0.61; tibiotarsus length: w_i = 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.

Use of feathers to assess polychlorinated biphenyl and organochlorine pesticide exposure in top predatory bird species of Pakistan

Little is known about the levels of organochlorines (OCs) in predatory bird species from Asia or the factors governing their concentrations. This study is the first report on concentrations of polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in predatory birds of Pakistan. The concentrations of PCBs and OCPs were investigated using tail feathers of ten different species of predatory birds. In addition, concentration differences among body, tail, primary and secondary feathers were investigated for six individuals of black kite (Milvus migrans). Ranges of concentrations were highest for dichlorodiphenyldichloroethylene (p,p'-DDE: 0.11-2163ngg(-1) dry wt.) followed by dichlorodiphenyltrichloroethane (p,p'-DDT: 0.36-345ngg(-1) dry wt.), hexachlorobenzene (HCB: 0.02-34ngg(-1) dry wt.), ∑PCBs (0.03-16ngg(-1) dry wt.) and trans-nonachlor (TN; 0.01-0.13ngg(-1) dry wt.). CB 118, 153, 138, and 180 along with p,p'-DDE were found as the most prevalent compounds. ∑PCBs and ∑DDTs were significantly different among species (both p<0.01) and omnivorous, scavengers, carnivorous and piscivorous trophic guilds (all p<0.03). Only ∑PCBs were significantly differentamong different families of birds (p<0.01). Values of stable isotopes (δ(13)C and δ(15)N) differed significantly (all p<0.01) among species, families, trophic guilds as well as terrestrial and aquatic habitat but not between nocturnal and diurnal predators (p=0.22 for δ(13)C; p=0.50 for δ(15)N). Concentrations of ∑PCBs, ∑DDTs and trans-nonachlor, but not HCB (p=0.86), were significantly different among different feather types (all p<0.01). Trophic and taxonomic affiliation as well as dietary carbon sources (δ(13)C) for species were identified as the variables best explaining the observed variation in exposure to the studied compounds. The significance of contributing factors responsible for OC contamination differences in predatory birds should be further elucidated in future studies.

Organochlorine Pesticides in the Ferruginous Pygmy Owl (Glaucidium brasilianum) in Chiapas, Mexico

Concentrations of organochlorine pesticides were quantified in samples of feathers (n = 17) and blood (n = 15) of the ferruginous pygmy owl (Glaucidium brasilianum). The individuals were captured near the Protected Natural Area Cerro Sonsonate, Chiapas, Mexico, between February and June 2014. In both tissues, pesticides belonging to seven organochlorine chemical families were detected. However, the organochlorine pesticide concentrations differed between feathers and blood. The highest concentrations of hexachlorocyclohexanes were found in feathers (0.63 ± 0.89 μg/g), whereas the highest concentrations of ΣDrines were found in blood (0.31 ± 0.47 μg/mL). By using the summed concentrations for each of the seven families of pesticides found in feathers, we did not find any significant correlation between the pesticides and pectoral muscle or body weight (p > 0.15). The ΣDDT group was the only pesticide family that showed a positive correlation with owl body weight (r = 0.60, p = 0.05); the concentrations of these pesticides were also high in feather and blood tissues (r = 0.87, p = 0.02). Our results confirm that ferruginous pygmy owls in the study area are exposed to these pesticides.

Tracking pan-continental trends in environmental contamination using sentinel raptors-what types of samples should we use?

Biomonitoring using birds of prey as sentinel species has been mooted as a way to evaluate the success of European Union directives that are designed to protect people and the environment across Europe from industrial contaminants and pesticides. No such pan-European evaluation currently exists. Coordination of such large scale monitoring would require harmonisation across multiple countries of the types of samples collected and analysed-matrices vary in the ease with which they can be collected and the information they provide. We report the first ever pan-European assessment of which raptor samples are collected across Europe and review their suitability for biomonitoring. Currently, some 182 monitoring programmes across 33 European countries collect a variety of raptor samples, and we discuss the relative merits of each for monitoring current priority and emerging compounds. Of the matrices collected, blood and liver are used most extensively for quantifying trends in recent and longer-term contaminant exposure, respectively. These matrices are potentially the most effective for pan-European biomonitoring but are not so widely and frequently collected as others. We found that failed eggs and feathers are the most widely collected samples. Because of this ubiquity, they may provide the best opportunities for widescale biomonitoring, although neither is suitable for all compounds. We advocate piloting pan-European monitoring of selected priority compounds using these matrices and developing read-across approaches to accommodate any effects that trophic pathway and species differences in accumulation may have on our ability to track environmental trends in contaminants.

Contaminants in the southern tip of South America: Analysis of organochlorine compounds in feathers of avian scavengers from Argentinean Patagonia

The aim of this study was to assess the exposure to organochlorine compounds (OC) in 91 primary wing feathers of avian scavengers, Turkey vulture (Cathartes aura), American black vulture (Coragyps atratus) and Southern crested caracaras (Polyborus plancus) from the southern tip of South America, in the Argentinean Patagonia. We analyzed for a series of OC including hexachlorocyclohexane (HCH) isomers, endosulfan, aldrin, dieldrin, endrin, dichlorodiphenyltrichloroethane (p,p'-DDT), dichlorodiphenyldichloroethane (p,p'-DDD), dichlorodiphenyldichloroethylene (p,p'-DDE), heptachlor and heptachlor-epoxide. This is the first study on OC in feathers of three terrestrial top carnivores from South America. OC concentrations found in the studied species were much higher than those found in feathers of raptors from Europe and Asia, which likely indicate their high use in the region, specifically in agriculture, and other possible uses of OC in this area. ∑HCH had the highest median concentration, followed by ∑Drins, ∑DDT, ∑Heptachlor, and ∑Endosulfan, similar to those reported in several food samples in Argentina. On the other hand, differences in OC profiles between species and areas may be related to feeding and migratory habits, as well as the molt period. Three individuals showed ∑DDT (DDT, DDD and DDE) concentrations in feathers related to sublethal effects. However, this comparison should be used with caution due to problems with extrapolating such data across tissues and species.

Polybrominated diphenyl ethers (PBDEs) in eggshells of the Southern Ground-Hornbill (Bucorvus leadbeateri) and Wattled Crane (Bugeranus carunculatus) in South Africa

This study was undertaken to assess the levels of eight PBDE congeners, namely: PBDE-17, 47, 100, 99, 154, 153, 183 and 209 in eggshells of Southern Ground-Hornbill (SGH) Bucorvus leadbeateri and Wattled Crane (WC) Bugeranus carunculatus obtained from different nesting sites within the eastern savanna of Limpopo Province and the midlands of KwaZulu-Natal, respectively. Analyses were performed using gas chromatography–mass spectrometry employing the electron impact ionization technique. The results obtained indicated that the lower brominated congeners were predominant in both species. The total PBDEs ranged between not detected (ND) to 264 μg g−1 lipid weight and 5.98–7146 μg g−1 lipid weight in the SGH and WC samples, respectively. More so, the mean recoveries of the 13C-labelled surrogate standards ranged between 40% (PBDE-100) and 136% (PBDE-99). The potential hazards to these birds via PBDEs exposure were evaluated by determining the hazard quotients (HQs) by employing the established Lowest Observed Effect Level (LOEL) values associated with impaired pipping and hatching success as well as that associated with impaired reproduction. HQs values varying from 0.58 to 0.94 and 27.71 to 45.27, respectively were obtained for SGH and WC species. This implies that the SGH populations are exposed to low to moderate hazards, while the WC populations are susceptible to high hazards. Considering the potential threats posed by PBDEs, particularly to the WC species, it is likely that exposure to the current environmental levels of PBDEs by these birds may contribute to their reduced breeding success and declining population trends.

The use of feathers of birds of prey as indicators of metal pollution

Published results concerning metal levels in feathers of birds of prey were listed and evaluated. Mercury concentrations have been studied most and the background values normally vary between 0.1 and 5 mg/kg dry weight the highest concentrations being in birds from aquatic food chains. Pollution causes elevated levels of mercury in feathers. The concentrations of cadmium, copper, lead and zinc show reasonable variation between species, areas and time periods. Feathers of birds of prey have proved to be good indicators of the status of environmental heavy metal pollution. Special attention should be paid to clean sampling and preparation of samples. Interpretation of the results requires knowledge on food habit, molting and migration patterns of the species. Several species representing different food chains should be included in comprehensive monitoring surveys. Chick feathers reflect most reliably local conditions.

Contaminants in indigenous harvests of apex predators: the Tasmanian Short-tailed Shearwater as a case study

The Short-tailed Shearwater (Puffinus tenuirostris), or muttonbird, migrates between hemispheres and is subject to an annual harvest at its breeding grounds in Tasmania. As top predators, these seabirds are exposed to high concentrations of contaminants. Concentrations of total polychlorinated biphenyls (PCBs) and 22 elements were determined in Short-tailed Shearwater muscle to evaluate the safety of this meat product for human consumption. Among muscle samples, 57 per cent exceeded food safety standards for either lead (>0.10 μg/g wet weight (ww)) or copper (>0.01 μg/g ww/kg body mass). All muscle samples had total PCB concentrations below the limit of detection (<0.01 μg/g ww). We also sampled feathers to investigate their utility in predicting internal contaminant burdens. Feather-muscle relationships among elements were generally poor, especially for toxicologically important elements (As, Cd, Hg, Pb), limiting the utility of feathers to monitor internal contaminant concentrations. There are no existing monitoring programs for contaminants in harvested wild birds in Australia, and we urge a greater integration between human and wildlife health studies, especially in remote areas where harvesting wildlife is more prevalent, culturally important, and forms a significant component of human diets.

Feathers as a biomonitoring tool of polyhalogenated compounds: a review

Feathers have many advantages that make them an excellent nondestructive tool for monitoring polyhalogenated compounds (PHCs). This paper proposes a review on the PHCs in feathers and factors influencing the pollutant load. Special attention has given to external contamination and the main analytical methods used to detect these compounds in feathers. Some authors have found strong and significant correlations between the concentrations of PHCs in feathers and internal tissues, providing positive expectations for their future use in the field of ecotoxicology. However, changes in diet, time elapsed between the previous molt period and sampling, sample size, and/or external contamination have been suggested as possible causes to explain the lack of correlations reported in some studies. Further studies with newly grown feathers and blood samples would be required in order to clarify this issue. Although atmospheric deposition has been reported as cause of external contamination, preening oil seems to be the most relevant factor contributing to this process. Unfortunately, washing techniques tested to date are not able to effectively remove the surface contamination from barbs and shafts, and therefore, it is necessary to develop methods able to discriminate between internal and external contamination. Finally, in this review, deposition rate is proposed as a measurement unit, as this allows comparisons between different parts of the same feather, as well as between different feathers.

Perfluoroalkyl substances in soft tissues and tail feathers of Belgian barn owls (Tyto alba) using statistical methods for left-censored data to handle non-detects

Perfluoroalkyl substances (PFASs) were investigated in tail feathers and soft tissues (liver, muscle, preen gland and adipose tissue) of barn owl (Tyto alba) road-kill victims (n=15) collected in the province of Antwerp (Belgium). A major PFAS producing facility is located in the Antwerp area and levels of PFASs in biota from that region have been found to be very high in previous studies. We aimed to investigate for the first time the main sources of PFASs in feathers of a terrestrial bird species. Throughout this study, we have used statistical methods for left-censored data to cope with levels below the limit of detection (LOD), instead of traditional, potentially biased, substitution methods. Perfluorooctane sulfonate (PFOS) was detected in all tissues (range: 11ng/g ww in muscle-1208ng/g ww in preen oil) and in tail feathers (<2.2-56.6ng/g ww). Perfluorooctanoate (PFOA) was measured at high levels in feathers (<14-670ng/g ww), but not in tissues (more than 50%<LOD). Perfluorohexane sulfonate (PFHxS) could only be quantified in liver and preen oil, while other PFASs were sporadically detected in liver. PFOS levels in feathers and liver were highly correlated (r=0.78, p<0.01), in contrast to PFOA (r=-0.11, p=0.78). Combined with high PFOA levels in feathers this suggests that PFOA may be present on the external surface of feathers, due to external contamination originating from the air in the vicinity of point sources. Therefore the possibility of using feathers as a passive air sampler for high PFOA levels should be investigated in the future.

Razorbills (Alca torda) as bioindicators of mercury pollution in the southwestern Mediterranean

Levels of mercury (Hg) were analyzed in the tissues of 50 Razorbills (Alca torda), from the Mediterranean area, which had drowned in fishing nets. The mercury distribution pattern in tissues was similar to those of other studies (liver > feather vane > kidney > muscle > brain > feather shaft), with mercury concentrations of 2.85 ± 0.90, 2.66 ± 1.60, 2.23 ± 0.87, 1.54 ± 0.54, 1.48 ± 0.54 and 1.30 ± 0.76 mg/kg (dry weight), respectively. It could be considered that Razorbills in the southwestern Mediterranean were chronically exposed to relatively low levels of MeHg, probably below 0.5 ppm, via dietary intake. We have proposed prediction equations for brain and kidney Hg concentrations using feather shafts as non-invasive samples. This work provides a solid understanding of Razorbill Hg exposure both in their wintering and breeding grounds, and shows that this species can be useful for assessing marine environmental health in the Mediterranean area.

Ecophysiology of avian migration in the face of current global hazards

Long-distance migratory birds are often considered extreme athletes, possessing a range of traits that approach the physiological limits of vertebrate design. In addition, their movements must be carefully timed to ensure that they obtain resources of sufficient quantity and quality to satisfy their high-energy needs. Migratory birds may therefore be particularly vulnerable to global change processes that are projected to alter the quality and quantity of resource availability. Because long-distance flight requires high and sustained aerobic capacity, even minor decreases in vitality can have large negative consequences for migrants. In the light of this, we assess how current global change processes may affect the ability of birds to meet the physiological demands of migration, and suggest areas where avian physiologists may help to identify potential hazards. Predicting the consequences of global change scenarios on migrant species requires (i) reconciliation of empirical and theoretical studies of avian flight physiology; (ii) an understanding of the effects of food quality, toxicants and disease on migrant performance; and (iii) mechanistic models that integrate abiotic and biotic factors to predict migratory behaviour. Critically, a multi-dimensional concept of vitality would greatly facilitate evaluation of the impact of various global change processes on the population dynamics of migratory birds.

Razorbill (Alca torda) feathers as an alternative tool for evaluating exposure to organochlorine pesticides

The aim of this study was to explore the usefulness of feathers as a biomonitoring tool for organochlorine pesticides (OC) in a razorbill population (Alca torda). Fifteen OC were analyzed in feathers, including α-, β- and δ-hexachlorocyclohexane, lindane, aldrin, dieldrin, endrin, endosulfan I and II, endosulfan sulfate, p,p'-DDT, DDD, DDE, heptachlor and its epoxide. The geometric mean concentrations observed in this study were ∑DDT 67.40 ng/g, ∑HCH 62.88 ng/g, ∑Heptachlor 61.75 ng/g, ∑Endosulfan 19.70 ng/g, and ∑Drins 10.17 ng/g. The higher OC levels found in this study compared with other studies are probably affected by the razorbill diet and migration status. However, levels found in the feathers of the present study are related to concentrations in internal tissues below those which cause adverse reproductive and behavioral effects or other signs of organochlorine-pesticide poisoning in birds. Age does affect the concentration of OC pesticides in feathers. Thus, feathers would appear to be a promising tool for OC biomonitoring in seabirds, since it is possible to quantify OC compounds.

A comparison of non-destructive sampling strategies to assess the exposure of white-tailed eagle nestlings (Haliaeetus albicilla) to persistent organic pollutants

To circumvent difficulties associated with monitoring adult predatory birds, we investigated the feasibility of different non-destructive strategies for nestling white-tailed eagles (Haliaeetus albicilla). We were able to quantify polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs) and organochlorinated pesticides (OCPs) in body feathers (16.92, 3.37 and 7.81ngg(-1) dw, respectively), blood plasma (8.37, 0.32 and 5.22ngmL(-1) ww, respectively), and preen oil (1157.95, 30.92 and 440.74ngg(-1) ww, respectively) of all nestlings (N=14). Strong significant correlations between blood plasma and preen oil concentrations (0.565≤r≤0.801; P<0.05) indicate that preen oil levels closely reflect the internal state of contamination. We found fewer significant correlations between body feather and blood plasma concentrations, which were almost exclusively between PCB concentrations (0.554≤r≤0.737; P<0.05). These results differ from a previous study on younger nestlings, and may indicate that the nestlings studied here, ready to fledge the nest, were possibly undergoing certain physiological changes that may have confounded the use of body feathers as biomonitor matrix. Finally, we provide an integrated discussion on the use of body feathers and preen oil as non-destructive biomonitor strategies for nestling predatory birds.

Body feathers as a potential new biomonitoring tool in raptors: a study on organohalogenated contaminants in different feather types and preen oil of West Greenland white-tailed eagles (Haliaeetus albicilla)

We investigated the variation in concentrations and profiles of various classes of organohalogenated compounds (OHCs) in different feather types, muscle tissue and preen oil from 15 white-tailed eagle (Haliaeetus albicilla) carcasses from Greenland. The influence of moult patterns and potential external contamination onto the feather surface was examined, while the present study is also the first to investigate the use of body feathers for OHC monitoring. Concentrations of sum polychlorinated biphenyls (PCBs) in feathers from white tailed eagles ranged from 2.3 ng/g in a primary wing feather to 4200 ng/g in body feathers. Using 300 mg of body feathers, almost 50 different OHCs could be quantified and median concentrations in body feathers were 10 fold higher than concentrations in tail feathers (rectrices) or primary wing feathers. Body feathers could be very useful for biomonitoring taking into account their easy sampling, short preparation time and high levels of OHCs. In addition, the effects of confounding variables such as feather size, moult and age are also minimised using body feathers. Correlations with concentrations in muscle tissue and preen oil were high and significant for all feather types (r ranging from 0.81 to 0.87 for sum PCBs). Significant differences in concentrations and profiles of OHCs were found between different primary feathers, indicating that the accumulation of OHCs in feathers varies over the moulting period (maximum three years). Washing of feathers with an organic solvent (acetone) resulted in a significant decrease in the measured concentrations of OHCs in feathers. However, our results indicated that preen oil is probably not the only contributor to the external contamination that can be removed by washing with acetone. Possibly dust and other particles may be of importance and may be sticking to the preened feathers. Rectrices washed only with water showed high and significant correlations with concentrations in muscle and preen oil as well. Washing with acetone therefore does not seem to be of great influence when relating to internal tissue concentrations. We recommend washing feathers only with distilled water in order to remove dirt and dust particles before analysis.

Polybrominated diphenyl ethers (PBDEs) in feathers of colonial water-bird species from Pakistan

Feathers of two colonial water-birds species (Bubulcus ibis, Egretta garzetta) from four heronries in the Punjab province, Pakistan were analysed for 28 Polybrominated Diphenyl Ethers (PBDEs) congeners. Median concentrations of ∑PBDEs were 2.41 and 1.91 ng/g in little and cattle egrets. PBDE-47, -100, -138, -153 were abundant and detected in >70% of feather samples in both species. Species-specific differences based on dietary preferences indicated higher concentration of PBDE-47, -66, -75, -100, -153, -154, and -183 in fish eating little egret. BDE-47 and -100 were more frequent in little egrets and BDE-99 was more dominant in cattle egret which feed on terrestrial habitat. Higher ∑hexa- and hepta-BDEs congeners showed larger concentrations in feathers from heronries close to water bodies which receive urban and industrial effluents whereas lower-brominated congeners (BDE-47-BDE-100) dominated in rural/agricultural regions. Hazard quotients (HQs) indicated that measured ∑PBDEs pose no risk to egret population.

A first evaluation of the usefulness of feathers of nestling predatory birds for non-destructive biomonitoring of persistent organic pollutants

In previous studies, feathers of adult predatory birds have been evaluated as valid non-destructive biomonitor matrices for persistent organic pollutants (POPs). In this study, we assessed for the first time the usefulness of nestling raptor feathers for non-destructive biomonitoring of POPs. For this purpose, we collected body feathers and blood of nestlings from three avian top predators from northern Norway: northern goshawks (Accipiter gentilis), white-tailed eagles (Haliaeetus albicilla) and golden eagles (Aquila chrysaetos). We were able to detect a broad spectrum of legacy POPs in the nestling feathers of all three species (Σ PCBs: 6.78-140ng g(-1); DDE: 3.15-145ng g(-1); Σ PBDEs: 0.538-7.56ng g(-1)). However, these concentrations were lower compared to other studies on raptor species, probably due to the aspect of monitoring of nestlings instead of adults. Besides their analytical suitability, nestling feathers also appear to be biologically informative: concentrations of most POPs in nestling feathers showed strong and significant correlations with blood plasma concentrations in all species (p<0.050; 0.775<r<0.994). In addition, the reported correlations between feathers and blood plasma were much higher than those previously reported for adult individuals. Accumulation profiles and species-specific differences were in accordance with other toxicological studies on avian species and generally in agreement with the specific ecology of the studied species. In summary, our results indicate that the use of nestling feathers of northern raptors may be a valid and promising non-destructive biomonitoring strategy for POPs in their ecosystems.

A screening of persistent organohalogenated contaminants in hair of East Greenland polar bears

In this pilot study, we report on levels of persistent organohalogenated contaminants (OHCs) in hair of polar bears (Ursus maritimus) from East Greenland sampled between 1999 and 2001. To our knowledge, this is the first study on the validation of polar bear hair as a non-invasive matrix representative of concentrations and profiles in internal organs and blood plasma. Because of low sample weights (13-140mg), only major bioaccumulative OHCs were detected above the limit of quantification: five polychlorinated biphenyl (PCB) congeners (CB 99, 138, 153, 170 and 180), one polybrominated diphenyl ether (PBDE) congener (BDE 47), oxychlordane, trans-nonachlor and β-hexachlorocyclohexane. The PCB profile in hair was similar to that of internal tissues (i.e. adipose, liver, brain and blood), with CB 153 and 180 as the major congeners in all matrices. A gender difference was found for concentrations in hair relative to concentrations in internal tissues. Females (n=6) were found to display negative correlations, while males (n=5) showed positive correlations, although p-values were not found significant. These negative correlations in females may reflect seasonal OHC mobilisation from periphery adipose tissue due to, for example, lactation and fasting. The lack of significance in most correlations may be due to small sample sizes and seasonal variability of concentrations in soft tissues. Further research with larger sample weights and sizes is therefore necessary to draw more definitive conclusions on the usefulness of hair for biomonitoring OHCs in polar bears and other fur mammals.

Application of mass spectrometry in the analysis of polybrominated diphenyl ethers

This review summarized the applications of mass spectrometric techniques for the analysis of the important flame retardants polybrominated diphenyl ethers (PBDEs) to understand the environmental sources, fate and toxicity of PBDEs that were briefly discussed to give a general idea for the need of analytical methodologies. Specific performance of various mass spectrometers hyphenated with, for example, gas chromatograph, liquid chromatograph, and inductively coupled plasma (GC/MS, LC/MS, and ICP/MS, respectively) for the analysis of PBDEs was compared with an objective to present the information on the evolution of MS techniques for determining PBDEs in environmental and human samples. GC/electron capture negative ionization quadrupole MS (GC/NCI qMS), GC/high resolution MS (GC/HRMS) and GC ion trap MS (GC/ITMS) are most commonly used MS techniques for the determination of PBDEs. New analytical technologies such as fast tandem GC/MS and LC/MS become available to improve analyses of higher PBDEs. The development and application of the tandem MS techniques have helped to understand environmental fate and transformations of PBDEs of which abiotic and biotic degradation of decaBDE is thought to be one major source of Br(1-9)BDEs present in the environment in addition to direct loading from commercial mixtures. MS-based proteomics will offer an insight into the molecular mechanisms of toxicity and potential developmental and neurotoxicity of PBDEs.

Flaws and pitfalls in the chemical analysis of feathers: bad news-good news for avian chemoecology and toxicology

Ecologists have frequently used biochemical assays as proxies for processes or phenomena too difficult to explore by traditional means of investigation. Feathers have been subjected to a number of chemical analyses to study such things as their elemental composition, contaminants, and hormones. The reliance on standard methodology of using concentrations to express quantities of chemical substances is seriously problematic because it creates artifacts by ignoring the physiology of feathers. Some elements and compounds are incorporated into the feather as part of the very building blocks of the keratin. However, others that are less functionally important to feathers (but not necessarily to the bird) enter the developing cells in proportion to their abundance in the bloodstream; in other words, feathers are merely receptacles, and deposition of chemicals is time dependent. In the latter case, one that applies to much of the work done on feather chemistry, data expressed as concentrations are meaningless because the varying mass across the feather alters concentrations in a way that has no biological significance. I discuss this problem and various pitfalls in the chemical analysis of feathers, and offer solutions that ultimately will offer a better understanding of the mechanisms influencing feather composition and, thus, the ecological patterns and processes they were meant to study.