Integrating active and passive monitoring to assess sublethal effects and mortality from lead poisoning in birds of prey

Lead poisoning of raptors: state of the science and cross-discipline mitigation options for a global problem

Lead poisoning is an important global conservation problem for many species of wildlife, especially raptors. Despite the increasing number of individual studies and regional reviews of lead poisoning of raptors, it has been over a decade since this information has been compiled into a comprehensive global review. Here, we summarize the state of knowledge of lead poisoning of raptors, we review developments in manufacturing of non-lead ammunition, the use of which can reduce the most pervasive source of lead these birds encounter, and we compile data on voluntary and regulatory mitigation options and their associated sociological context. We support our literature review with case studies of mitigation actions, largely provided by the conservation practitioners who study or manage these efforts. Our review illustrates the growing awareness and understanding of lead exposure of raptors, and it shows that the science underpinning this understanding has expanded considerably in recent years. We also show that the political and social appetite for managing lead ammunition appears to vary substantially across administrative regions, countries, and continents. Improved understanding of the drivers of this variation could support more effective mitigation of lead exposure of wildlife. This review also shows that mitigation strategies are likely to be most effective when they are outcome driven, consider behavioural theory, local cultures, and environmental conditions, effectively monitor participation, compliance, and levels of raptor exposure, and support both environmental and human health.

Third-generation cephalosporin resistant Escherichia coli in dogs and cats in Germany in 2019-2021

OBJECTIVES

Antimicrobial resistance (AMR) poses a worldwide challenge, threatening global health. The objective of this research was to determine the 3rd generation cephalosporin resistance (3GCR) proportion in Escherichia (E.) coli isolated from clinical samples of dogs and cats in Germany.

METHODS

The study utilized result data from antimicrobial susceptibility testing (AST) of isolates obtained from diagnostic samples collected from dogs and cats send in for bacterial examination. Data includes AST results from 3,491 veterinary practices in Germany spanning the years 2019 to 2021, representing 33.1% of practices and clinics nationwide. Out of 175,171 clinical samples, a total of 25,491 E. coli strains (14,6%) were evaluated for their susceptibility to antimicrobials, in particular the 3rd generation cephalosporin cefovecin, but also aminoglycosides (gentamicin, GEN), fluoroquinolones (enrofloxacin, ENR), tetracyclines (doxycycline), phenicols (chloramphenicol), folate pathway inhibitors (sulfamethoxazole + trimethoprim), and nitrofurans (nitrofurantoin).

RESULTS

The cefovecin resistance proportion was 11.6% in the study period. Geographical analysis showed local variations in 3GCR in E. coli of ±3%. Regarding all E. coli isolates investigated, resistance proportions were observed as follows: 12% for sulfamethoxazole-trimethoprim, 7% for enrofloxacin, 8% for chloramphenicol and 4% for gentamicin. Notably, 3GCR E. coli showed significantly higher resistance proportions, specifically 30% for sulfamethoxazole-trimethoprim, 28% for chloramphenicol, 18% for enrofloxacin and 14% for gentamicin.

CONCLUSIONS

This study represents the first of its kind to utilize an extensive dataset encompassing dogs and cats across Germany. Companion animals have close contact to their owners and transmission of 3GCR between them is likely as well as acquisition from other environmental sources. Resistance proportions (6.7%) against the antibiotic ceftazidime as reported by the German AMR surveillance for human medicine were lower than in our veterinary data. Our study provides an overview of the current 3GCR resistance proportion in Germany and demonstrates the importance of integrated AMR monitoring.

Elevated Heavy Metal(loid) Blood and Feather Concentrations in Wetland Birds from Different Trophic Levels Indicate Exposure to Environmental Pollutants

The research assessed the exposure to total mercury (THg), lead (Pb), and arsenic (As) in Colombian wetland species of different trophic levels Platalea ajaja, Dendrocygna autumnalis and Nannopterum brasilianus. The results show high THg blood levels in P. ajaja (811.00 ± 349.60 µg L-1) and N. brasilianus (209.50 ± 27.92 µg L-1) with P. ajaja possibly exhibiting adverse effects. Blood Pb concentration was high in D. autumnalis (212.00 ± 208.10 µg L-1) and above the threshold for adverse effects, suggesting subclinical poisoning. Levels of blood As were below the assumed threshold for detrimental effect (20 μg L-1). The mean concentration of feather THg was below the assumed natural background levels (5 µg g-1) for all three species. Feather Pb levels exceeded the levels for assumed threshold effects in all sampled N. brasilianus (7.40 ± 0.51 µg g-1). Results for feather As concentration were below the threshold for adverse impacts in all species, although a positive correlation between As and THg concentrations was detected in P. ajaja feathers. The overall results could help understand how metal(loid)s biomagnify through trophic levels and how wetland species may serve as environmental indicators. By exploring the interactions of metal(loid)s within different matrices and body, this study offers insights into the dynamics of contaminant accumulation and distribution in the environment. This concept can be applied to wetlands worldwide, where bird species can serve as indicators of ecosystem health and the presence of contaminants such as heavy metals and metalloids.

Blood lead levels in an endangered vulture decline following changes in hunting activity

Lead ammunition stands out as one of the most pervasive pollutants affecting wildlife. Its impact on bird populations have spurred efforts for the phase-out of leaded gunshot in several countries, although with varying scopes and applications. Ongoing and future policy changes require data to assess the effectiveness of adopted measures, particularly in the current context of biodiversity loss. Here, we assessed the long-term changes in blood lead (Pb) levels of Egyptian vultures from the Canary Islands, Spain, which have been severely affected by Pb poisoning over the past two decades. During this period, the reduction in hunting pressure and changes in legislation regarding firearms usage for small game hunting likely contributed to a decrease in environmental Pb availability. As anticipated, our results show a reduction in Pb levels, especially after the ban on wild rabbit hunting with shotgun since 2010. This effect was stronger in the preadult fraction of the vulture population. However, we still observed elevated blood Pb levels above the background and clinical thresholds in 5.6% and 1.5% of individuals, respectively. Our results highlight the positive impact of reducing the availability of Pb from ammunition sources on individual health. Nonetheless, the continued use of Pb gunshot remains an important source of poisoning, even lethal, mainly affecting adult individuals. This poses a particular concern for long-lived birds, compounding by potential chronic effects associated with Pb bioaccumulation. Our findings align with recent studies indicating insufficient reductions in Pb levels among European birds of prey, attributed to limited policy changes and their uneven implementation. We anticipated further reductions in Pb levels among Egyptian vultures with expanded restrictions on hunting practices, including a blanket ban on Pb shot usage across all small game species.

Toxicological effects assessment for wildlife in the 21st century: Review of current methods and recommendations for a path forward

Model species (e.g., granivorous gamebirds, waterfowl, passerines, domesticated rodents) have been used for decades in guideline laboratory tests to generate survival, growth, and reproductive data for prospective ecological risk assessments (ERAs) for birds and mammals, while officially adopted risk assessment schemes for amphibians and reptiles do not exist. There are recognized shortcomings of current in vivo methods as well as uncertainty around the extent to which species with different life histories (e.g., terrestrial amphibians, reptiles, bats) than these commonly used models are protected by existing ERA frameworks. Approaches other than validating additional animal models for testing are being developed, but the incorporation of such new approach methodologies (NAMs) into risk assessment frameworks will require robust validations against in vivo responses. This takes time, and the ability to extrapolate findings from nonanimal studies to organism- and population-level effects in terrestrial wildlife remains weak. Failure to adequately anticipate and predict hazards could have economic and potentially even legal consequences for regulators and product registrants. In order to be able to use fewer animals or replace them altogether in the long term, vertebrate use and whole organism data will be needed to provide data for NAM validation in the short term. Therefore, it is worth investing resources for potential updates to existing standard test guidelines used in the laboratory as well as addressing the need for clear guidance on the conduct of field studies. Herein, we review the potential for improving standard in vivo test methods and for advancing the use of field studies in wildlife risk assessment, as these tools will be needed in the foreseeable future. Integr Environ Assess Manag 2024;20:699-724. © 2023 His Majesty the King in Right of Canada and The Authors. Integrated Environmental Assessment and Management published by Wiley Periodicals LLC on behalf of Society of Environmental Toxicology & Chemistry (SETAC). Reproduced with the permission of the Minister of Environment and Climate Change Canada. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.

Exposure to Persistent Organic Pollutants in Australian Waterbirds

There is growing worldwide recognition of the threat posed by persistent organic pollutants (POPs) to wildlife populations. We aimed to measure exposure levels to POPs in a Southern Hemisphere aquatic waterbird species, the nomadic gray teal (Anas gracilis), which is found across Australia. We collected wings from 39 ducks harvested by recreational hunters at two sites (one coastal, one inland) in Victoria, southeastern Australia, in 2021. We examined three groups of POPs: nine congeners of polychlorinated biphenyls (PCBs), 13 organochlorine pesticides (OCPs), and 12 polycyclic aromatic hydrocarbons (PAHs). The PCBs, OCPs, and PAHs were detected at quantifiable levels in 13%, 72%, and 100% of birds, respectively. Of the congeners we tested for in PCBs, OCPs, and PAHs, 33%, 38%, and 100% were detected at quantifiable levels, respectively. The highest levels of exposure to POPs that we found were to the PAH benzo[b]fluoranthene, occurring at a concentration range of 1.78 to 161.05 ng/g wet weight. There were some trends detected relating to differences between geographical sites, with higher levels of several PAHs at the coastal versus inland site. There were several strong, positive associations among PAHs found. We discuss potential sources for the POPs detected, including industrial and agricultural sources, and the likely role of large-scale forest fires in PAH levels. Our results confirm that while Australian waterbirds are exposed to a variety of POPs, exposure levels are currently relatively low. Additional future investigations are required to further characterize POPs within Australian waterbird species. Environ Toxicol Chem 2024;43:736-747. © 2023 The Authors. Environmental Toxicology and Chemistry published by Wiley Periodicals LLC on behalf of SETAC.

Elevated lead (Pb) in urban European starling (Sturnus vulgaris) feathers is not correlated to physiology or behavior

Urbanization is rapidly changing the environment and creating new challenges in the lives of animals across the globe. Anthropogenic contaminants-like heavy metals-can persist within the environment for prolonged periods of time and present a widespread problem for those living near contaminated areas. Lead (Pb) was a commonly used heavy metal that continues to threaten the health of all organisms despite being phased out, especially in urban areas where historical use was more common. In this study, a common urban-adapter, the European starling (Sturnus vulgaris), was trapped to explore whether feather Pb burden is greater in birds from urban habitats than rural habitats, as well as whether Pb burdens were correlated with behavior, physiology, and feather development. Across four sites (two rural and two urban), soil Pb concentrations were measured and 197 free-living starlings were captured to measure feather Pb concentrations. Using linear mixed models, this study found that urban starling nestlings had elevated feather Pb burdens compared to rural nestlings. In contrast, there was no correlation between Pb and urbanization in adult birds whose exposure to Pb may reflect a larger spatial range compared to nestlings. For both nestlings and adults, feather Pb was uncorrelated to corticosterone, testosterone, aggressive behavior, or feather growth rates. These findings suggest that starlings may be a useful biomonitoring tool to detect Pb in the local environment, however, the age and spatial range of birds is a critical consideration in applying this tool. Further work is needed to understand the intricate relationship between heavy metals, behavior, morphological development, and physiology in free-living organisms.

Temporal and spatial trends in lead levels in the blood and down of Black Stork nestlings in central Europe

Young birds at an intensive growth stage are especially vulnerable to the deleterious effects of contaminants such as lead (Pb). This element negatively influences organs, development and even behavior, which can consequently lead to lower survival and reproductive success of the population. There was a suspicion that these mechanisms, along with other factors, retarded population growth of the Black Stork - still a heavily understudied species in respect to pollution, especially Pb. Therefore, we undertook a study concerning Pb concentrations in the down and blood of Black Stork nestlings from breeding grounds in central and southern Poland (Europe). To investigate the effects of Pb exposure on nestling condition, scale mass index and reduced glutathione levels were also studied, but results indicated that Pb did not influence either of these parameters. The highest blood Pb concentration reached 0.247 μg/g, while the highest down Pb concentrations was significantly higher reaching 4.95 μg/g. Concentrations in blood and down were not correlated with each other. Nest location and year of sampling were not influential for blood but were influential for down Pb concentrations. Relationships between Pb concentrations, habitat characteristics and proximity to emitters were not significant. Overall Pb concentrations in Black Stork nestlings were below the toxicity threshold and did not have negative effects on specimens studied. They were probably related to maternal exposure during migration, on stopover and breeding grounds as well as with food provided by parents.

Medicated livestock carcasses and landfill sites: Sources of highly toxic veterinary pharmaceuticals and caffeine for avian scavengers

Veterinary drugs are of concern in terms of potential environmental pollution and their negative impacts on avian scavengers. These pharmaceuticals reach vultures through the consumption of carcasses of previously treated livestock. Here, we analysed samples from livestock carcasses (n = 159), avian scavenger tissues (n = 116) and plasma (n = 312) for 49 compounds commonly used in veterinary medicine in Aragon (NE Spain) and nearby regions. Samples were analysed using liquid chromatography with electrospray ionization mass spectrometry (LC-ESI-MS/MS). We detected pharmaceuticals in 54.1% of livestock carcasses analysed (50.3% with antibiotics, 10.8% with NSAIDs). For veterinary pharmaceuticals in tissues and plasma from avian scavengers, we detected pharmaceuticals in 51.7% and 28.5% of samples, respectively. Antibiotics were detected in 50.9% and 25.3% while NSAIDs were determined in 6.0% and 5.5% of tissues and plasma from avian scavengers, respectively. Moreover, caffeine was detected in plasma in 73.7% of vultures sampled at landfill sites, indicating its usefulness as a biomarker of urban garbage ingestion. We found an association between livestock carcasses, especially pigs and chickens, and the presence of veterinary pharmaceuticals in avian scavengers. We highlight that carcass disposal for feeding avian scavengers must address the potential risks posed by veterinary pharmaceutical residues.

Molecular Mechanisms of Selenium Mitigating Lead Toxicity in Chickens via Mitochondrial Pathway: Selenoproteins, Oxidative Stress, HSPs, and Apoptosis

Lead (Pb), a hazardous heavy metal, can damage the health of organisms. However, it is not clear whether Pb can damage chicken cerebellums and thalami. Selenium (Se), an essential nutrient for organisms, has a palliative effect on Pb poisoning in chickens. In our experiment, a model of chickens treated with Pb and Se alone and in combination was established to investigate the molecular mechanism of Se alleviating Pb-caused damage in both chicken cerebellums and thalami. Our morphological results indicated that Pb caused apoptotic lesions, such as mitochondrial and nuclear damage. Further, the anti-apoptotic gene Bcl-2 decreased; on the contrary, four pro-apoptotic genes (p53, Bax, Cyt c, and Caspase-3) increased under Pb treatment, meaning that Pb caused apoptosis via the p53-Cyt c-Caspase-3 pathway. Furthermore, we further demonstrated that Pb elevated four HSPs (HSP27, HSP40, HSP70, and HSP90), as well as HSP70 took part in the molecular mechanism of Pb-caused apoptosis. In addition, we found that Pb exposure led to oxidative stress via up-regulating the oxidant H2O2 and down-regulating four antioxidants (CAT, SOD, GST, and GPx). Moreover, Pb decreased three Se-containing factors (Txnrd1, Txnrd2, and Txnrd3), further confirming that Pb caused oxidative stress. Interestingly, Se supplementation reversed the above changes caused by Pb and alleviated Pb-induced oxidative stress and apoptosis. A time dependency was demonstrated for Bcl-2, Bax, and Cyt c in the cerebellums, as well as CAT, GPx, and p53 in the thalami of Pb-exposed chickens. HSP70 in cerebellums and HSP27 in thalami were more sensitive than those in thalami and cerebellums, respectively, under Pb exposure. Pb-induced apoptosis of thalami was more severe than cerebellums. In conclusion, after Pb treatment, Txnrds mediated oxidative stress, oxidative stress up-regulated HSPs, and finally, HSP70 triggered apoptosis. Se supplementation antagonized Pb-induced oxidative stress and apoptosis via the mitochondrial pathway and selenoproteins in chicken cerebellums and thalami. This study provides new information for the mechanism of environmental pollutant poisoning and the detoxification of Se on abiotic stress.

Lead exposure of mainland Australia's top avian predator

Lead (Pb) toxicity, through ingestion of lead ammunition in carcasses, is a threat to scavenging birds worldwide, but has received little attention in Australia. We analyzed lead exposure in the wedge-tailed eagle (Aquila audax), the largest raptor species found in mainland Australia and a facultative scavenger. Eagle carcasses were collected opportunistically throughout south-eastern mainland Australia between 1996 and 2022. Lead concentrations were measured in bone samples from 62 animals via portable X-ray fluorescence (XRF). Lead was detected (concentration >1 ppm) in 84% (n = 52) of the bone samples. The mean lead concentration of birds in which lead was detected was 9.10 ppm (±SE 1.66). Bone lead concentrations were elevated (10-20 ppm) in 12.9% of samples, and severe (>20 ppm) in 4.8% of samples. These proportions are moderately higher than equivalent data for the same species from the island of Tasmania, and are comparable to data from threatened eagle species from other continents. Lead exposure at these levels is likely to have negative impacts on wedge-tailed eagles at the level of the individual and perhaps at a population level. Our results suggest that studies of lead exposure in other Australian avian scavenger species are warranted.

Heavy metal(loid) effect on multi-biomarker responses in apex predator: Novel assays in the monitoring of white stork nestlings

The goal of the present study was to investigate differences in biomarker responses related to metal(loid)s in white stork (Ciconia ciconia) nestling's blood from continental Croatia. To achieve this, a battery of biomarkers that can be affected by environmental pollutants, including metal(loid)s, was assessed (esterase activity, fluorescence-based oxidative stress biomarkers, metallothionein levels, glutathione-dependent enzyme activity). The research was conducted during the white stork breeding season in diverse areas (a landfill, industrial and agricultural sites, and an unpolluted area). White storks' nestlings near the landfill exhibited reduced carboxylesterase (CES) activity, elevated glutathione (GSH) concentration, as well as high Pb content in the blood. Increased As and Hg concentrations in blood were attributable to environmental contamination in agricultural area and an assumed unpolluted area, respectively. Furthermore, agricultural practices appeared to affect CES activity, as well as elevate Se levels. In addition to the successful implementation of biomarkers, present research showed that agricultural areas and a landfill are areas with increased metal(loid) levels possibly causing adverse effects on the white storks. This first-time heavy metal and metalloid analyses in the white stork nestlings from Croatia point to the necessary monitoring and future assessments of pollution impact to prevent irreversible adverse effects.

Elevated lead exposure in Australian hunting dogs during a deer hunting season

There is growing recognition of the threat posed by toxic lead-based ammunition. One group of domestic animals known to be susceptible to harmful lead exposure via this route is hunting dogs. Scent-trailing dogs ('hounds') are used to hunt introduced sambar deer (Cervus unicolor) during a prescribed eight-month (April-November) annual hunting season, during which they are fed fresh venison, in Victoria, south-eastern Australia. We used this annual season as a natural experiment to undertake longitudinal sampling of dogs for lead exposure. Blood was collected from 27 dogs owned by four different deer hunters and comprising three different breeds just prior to the start of the hound hunting season (March 2022) and in the middle of the season (August 2022), and blood lead levels (BLLs) (μg/dL) were determined via inductively coupled plasma mass spectrometry (ICP-MS). Using Tobit regression, the expected BLLs across all dogs were significantly lower before the season (0.50 μg/dL, standard error [SE] = 0.32 μg/dL) than during the season (1.39 μg/dL, SE = 0.35 μg/dL) (p = 0.01). However, when the breed of dog was included in the analyses, this effect was only significant in beagles (P < 0.001), not bloodhounds (p = 0.73) or harriers (p = 0.43). For 32% of the dogs before the season, and 56% during the season, BLLs exceeded the established threshold concentration for developmental neurotoxicity in humans (1.2 μg/dL). Time since most recent venison feeding, sex of dog and owner were not associated with BLLs. The finding that BLLs more than doubled during the hunting season indicates that lead exposure is a risk in this context. These results expand the sphere of impact from environmental lead in Australia from wild animals and humans, to include some groups of domestic animals, a textbook example of a One Health issue.

Naringin administration mitigates oxidative stress, anemia, and hypertension in lead acetate-induced cardio-renal dysfunction in cockerel chicks

Lead is one of the major pollutants that is harmful to both animals and humans. It is found in every aspect of the environment such as the air, water, and soil. This pollutant affects both wild and domestic birds. Naringin has an active principle called flavonoid that has been found to have medicinal properties, mostly because of its antioxidant and metal chelating properties. This study was carried out to investigate the protective effect of naringin as an antioxidant against lead-induced anemia, cardio and nephrotoxicity, and hypertension. This study also aimed at elucidating the use of naringin as a heavy metal binder in poultry feed. Thirty-six cockerel chicks were used for this study, and randomly grouped into six groups per group; group A served as the control, group B received Pb-only (300 ppm), group C (Pb and naringin; 80 mg/kg), group D (Pb and naringin; 160 mg/kg), group E (naringin 80 mg/kg), and group F (naringin 160 mg/kg), respectively, for 8 weeks. Lead (Pb) was administered via drinking water, while naringin was administered via oral gavage. Lead acetate intoxication precipitated anemia as indicated by significant reductions in the values of PCV, RBC, and Hb concentration in lead-treated chicks when compared with the controls. Also, lead administration induced hypertension together with increased oxidative stress, depletion of the antioxidant defense system, reduced nitric oxide production, and an increase in high blood pressure. Immunohistochemistry indicated high expressions of cardiac troponin, renal angiotensin-converting enzymes, and renal neutrophil gelatinase-associated lipocalin. Treatment with naringin corrected anemia, reduced oxidative stress, improved antioxidant system, reduced high blood pressure, and offered protection against lead acetate-induced cardio-renal dysfunction in cockerel chicks. We recommend that naringin should be incorporated poultry feeds as a metal binder.

Lead, cadmium, and other trace elements in the liver of golden eagles and white-tailed eagles: recent data from Poland and a systematic review of previous studies

The golden eagle (Aquila chrysaetos) and the white-tailed eagle (Haliaeetus albicilla), being apex predators and facultative scavengers, can bioaccumulate different environmental contaminants, including toxic elements that may adversely affect their health. We analyzed the levels of cadmium (Cd), lead (Pb), and other metals and metalloids, including arsenic (As), barium (Ba), beryllium (Be), cobalt (Co), chromium (Cr), copper (Cu), iron (Fe), magnesium (Mg), manganese (Mn), molybdenum (Mo), selenium (Se), thorium (Th), thallium (Tl), uranium (U), vanadium (V), and zinc (Zn) in liver samples taken from three golden eagles and 36 white-tailed eagles that were found dead across Poland to verify their exposure. We also used a systematic review to summarize the available literature data on Cd, Pb, and other studied elements in the liver of both eagle species. Analyses of trace elements in the liver samples of the Polish eagles revealed interspecific differences in Cd, Cu, and Mn and differences in Co, Mn, Tl, and Zn among study regions. All elements tested except Pb were below the suggested thresholds linked with adverse health effects in birds. The hepatic Pb found in almost half of all the tested individuals suggests environmental exposure to this toxic element. One of the tested white-tailed eagles had hepatic Pb above the threshold of sublethal poisoning. Although our results seem optimistic, as previous Polish studies showed a higher prevalence of birds with hepatic Pb exceeding the toxicity threshold, they indicate that exposure to this toxic metal could still pose an additional threat to the health of Polish eagles.

Second-generation anticoagulant rodenticides in the blood of obligate and facultative European avian scavengers

The widespread use of second-generation anticoagulant rodenticides (SGARs) and their high persistence in animal tissues has led to these compounds becoming ubiquitous in rodent-predator-scavenger food webs. Exposure to SGARs has usually been investigated in wildlife species found dead, and despite growing evidence of the potential risk of secondary poisoning of predators and scavengers, the current worldwide exposure of free-living scavenging birds to SGARs remains scarcely investigated. We present the first active monitoring of blood SGAR concentrations and prevalence in the four European obligate (i.e., vultures) and facultative (red and black kites) avian scavengers in NE Spain. We analysed 261 free-living birds and detected SGARs in 39.1% (n = 102) of individuals. Both SGAR prevalence and concentrations (ΣSGARs) were related to the age and foraging behaviour of the species studied. Black kites showed the highest prevalence (100%), followed by red kites (66.7%), Egyptian (64.2%), bearded (20.9%), griffon (16.9%) and cinereous (6.3%) vultures. Overall, both the prevalence and average ΣSGARs were higher in non-nestlings than nestlings, and in species such as kites and Egyptian vultures foraging in anthropic landscapes (e.g., landfill sites and livestock farms) and exploiting small/medium-sized carrions. Brodifacoum was most prevalent (28.8%), followed by difenacoum (16.1%), flocoumafen (12.3%) and bromadiolone (7.3%). In SGAR-positive birds, the ΣSGAR (mean ± SE) was 7.52 ± 0.95 ng mL^-1; the highest level detected being 53.50 ng mL^-1. The most abundant diastereomer forms were trans-bromadiolone and flocoumafen, and cis-brodifacoum and difenacoum, showing that lower impact formulations could reduce secondary exposures of non-target species. Our findings suggest that SGARs can bioaccumulate in scavenging birds, showing the potential risk to avian scavenging guilds in Europe and elsewhere. We highlight the need for further studies on the potential adverse effects associated with concentrations of SGARSs in the blood to better interpret active monitoring studies of free-living birds.

Determinants of the exposure of Eurasian griffon vultures (Gyps fulvus) to fluoroquinolones used in livestock: The role of supplementary feeding stations

Veterinary pharmaceuticals, including antibiotics, are emerging contaminants of concern worldwide. Avian scavengers are exposed to pharmaceuticals through consumption of livestock carcasses used for feeding wildlife for conservation purposes at supplementary feeding stations. Here we tested the hypothesis that griffon vultures (Gyps fulvus) would be more exposed to antibiotics (i.e., quinolones) when feeding on livestock carcasses from intensive farming than when they rely on carcasses from extensive farming or wild animals. We sampled 657 adult griffon vultures captured between 2008 and 2012. In addition, we sampled tissues from domestic livestock supplied at feeding stations in the study area between 2009 and 2019; pig (n = 114), sheep (n = 28), cow (n = 1) and goat (n = 2). Samples were analysed by liquid chromatography with electrospray ionization mass spectrometry (LC-ESI-MS). Quinolones were detected in plasma from 12.9% of the griffon vultures analysed. Quinolone prevalence in griffon vultures varied significantly among feeding stations but was also affected by the total amount of carcasses supplemented, especially the mass of pig carcasses. These results aligned with a 21.1% quinolone prevalence in pig carcasses sampled at feeding stations, wherein enrofloxacin and ciprofloxacin levels of up to 3359 ng/g and 1550 ng/g, respectively, were found. Given enrofloxacin pharmacokinetics in pig tissues, 5.3% of the analysed pigs may have died no more than one day after treatment. Quinolone presence in vultures was negatively associated with blood lead levels, which mostly originates from lead ammunition and indicates a higher consumption of game animal carcasses. Carcass disposal for feeding avian scavengers must always assess and manage the risks posed by veterinary pharmaceuticals, especially when livestock provided may have died soon after treatment.

Enhancing monitoring and transboundary collaboration for conserving migratory species under global change: The priority case of the red kite

Calls for urgent action to conserve biodiversity under global change are increasing, and conservation of migratory species in this context poses special challenges. In the last two decades the Convention on the Conservation of Migratory Species of Wild Animals (CMS) has provided a framework for several subsidiary instruments including action plans for migratory bird species, but the effectiveness and transferability of these plans remain unclear. Such laws and policies have been credited with positive outcomes for the conservation of migratory species, but the lack of international coordination and on-ground implementation pose major challenges. While research on migratory populations has received growing attention, considerably less emphasis has been given to integrating ecological information throughout the annual cycle for examining strategies to conserve migratory species at multiple scales in the face of global change. We fill this gap through a case study examining the ecological status and conservation of a migratory raptor and facultative scavenger, the red kite (Milvus milvus), whose current breeding range is limited to Europe and is associated with agricultural landscapes and restricted to the temperate zone. Based on our review, conservation actions have been successful at recovering red kite populations within certain regions. Populations however remain depleted along the southern-most edge of the geographic range where many migratory red kites from northern strongholds overwinter. This led us to a forward-looking and integrated strategy that emphasizes international coordination involving researchers and conservation practitioners to enhance the science-policy-action interface. We identify and explore key issues for conserving the red kite under global change, including enhancing conservation actions within and outside protected areas, recovering depleted populations, accounting for climate change, and transboundary coordination in adaptive conservation and management actions. The integrated conservation strategy is sufficiently general such that it can be adapted to inform conservation of other highly mobile species subject to global change.

Method to assess the potential magnitude of terrestrial European avian population reductions from ingestion of lead ammunition

Current estimates of terrestrial bird losses across Europe from ingestion of lead ammunition are based on uncertain or generic assumptions. A method is needed to develop defensible European-specific estimates compatible with available data that does not require long-term field studies. We propose a 2-step method using carcass data and population models. The method estimates percentage of deaths diagnosed as directly caused by lead poisoning as a lower bound and, as an upper bound, the percentage of possible deaths from sublethal lead poisoning that weakens birds, making them susceptible to death by other causes. We use these estimates to modify known population-level annual mortality. Our method also allows for potential reductions in reproduction from lead shot ingestion because reductions in survival and reproduction are entered into population models of species with life histories representative of the most groups of susceptible species. The models estimate the sustainability and potential population decreases from lead poisoning in Europe. Using the best available data, we demonstrate the method on two taxonomic groups of birds: gallinaceous birds and diurnal raptors. The direction of the population trends affects the estimate, and we incorporated such trends into the method. Our midpoint estimates of the reduction in population size of the European gallinaceous bird (< 2%) group and raptor group (2.9–7.7%) depend on the species life history, maximum growth rate, population trend, and if reproduction is assumed to be reduced. Our estimates can be refined as more information becomes available in countries with data gaps. We advocate use of this method to improve upon or supplement approaches currently being used. As we demonstrate, the method also can be applied to individual species of concern if enough data across countries are available.

Old World Vultures Reflect Effects of Environmental Pollutants Through Human Encroachment

African wildlife face challenges from many stressors including current and emerging contaminants, habitat and resource loss, poaching, intentional and unintentional poisoning, and climate-related environmental change. The plight of African vultures exemplifies these challenges due to environmental contaminants and other stressors acting on individuals and populations that are already threatened or endangered. Many of these threats emanate from increasing human population size and settlement density, habitat loss from changing land use for agriculture, residential areas, and industry, and climate-related changes in resource availability. Environmental chemicals that are hazardous include legacy chemicals, emerging chemicals of concern, and high-volume-use chemicals that are employed as weed killers and in other agricultural applications. Furthermore, there are differences in risk for species living in close proximity to humans or in areas affected by habitat loss, climate, and industry. Monitoring programs are essential to track the status of nesting pairs, offspring survival, longevity, and lifetime productivity. This is important for long-lived birds, such as vultures, that may be especially vulnerable to chronic exposure to chemicals as obligate scavengers. Furthermore, their position in the food web may increase risk due to biomagnification of chemicals. We review the primary chemical hazards to Old World vultures and the interacting stressors affecting these and other birds. Habitat is a major consideration for vultures, with tree-nesters and cliff-nesters potentially experiencing different risks of exposure to environmental chemicals. The present review provides information from long-term monitoring programs and discusses a range of these threats and their effects on vulture populations. Environ Toxicol Chem 2022;41:1586-1603. © 2022 SETAC.

The Impact of Pb from Ammunition on the Vegetation of a Bird Shooting Range

Hunting with lead ammunition represents a source of heavy metal pollution to the environment that can be potentially high at the local scale. Intensive hunting of small game species can concentrate high levels of ammunition discharging in small areas. This type of hunting is a relevant economic resource for private landowners in some regions of Spain, and current legislation allows the use of lead ammunition in these scenarios. It becomes, therefore, highly relevant to study whether this activity may pose concerns to the conservation of the environment in the areas where it takes place. Using a red-legged partridge (Alectoris rufa) shooting range as a study area, we examined the effect of intensive hunting on this species on the vegetation present. We found significantly higher lead levels in the sprouts of plants of shooting areas related to control sites of the same property where partridge shooting does not occur. We found differences in the presence of lead between sprouts of different plant species. In addition, old sprouts of existing vegetation in shooting areas also showed higher lead levels than newly emerged sprouts of the same plants. These results demonstrate the impact of lead ammunition on vegetation in terms of persistence over time and differences between species. Further analyses using chemical and ecotoxicological data are necessary to evaluate the extent of environmental pollution risks. Our results provide new support in favor of the use of alternative ammunition, with particular emphasis on scenarios where hunting activity is intensive.

Exposure of predatory and scavenging birds to anticoagulant rodenticides in France: Exploration of data from French surveillance programs

Wild raptors are widely used to assess exposure to different environmental contaminants, including anticoagulant rodenticides (ARs). ARs are used on a global scale for rodent control, and act by disruption of the vitamin K cycle that results in haemorrhage usually accompanied by death within days. Some ARs are highly persistent and bioaccumulative, which can cause significant exposure of non-target species. We characterized AR exposure in a heterogeneous sample of dead raptors collected over 12 years (2008-2019) in south-eastern France. Residue analysis of 156 liver samples through LC-MS/MS revealed that 50% (78/156) were positive for ARs, with 13.5% (21/156) having summed second-generation AR (SGAR) concentrations >100 ng/g ww. While SGARs were commonly detected (97.4% of positive samples), first-generation ARs were rarely found (7.7% of positive samples). ARs were more frequently detected and at greater concentration in predators (prevalence: 82.5%) than in scavengers (38.8%). Exposure to multiple ARs was common (64.1% of positive samples). While chlorophacinone exposure decreased over time, an increasing exposure trend was observed for the SGAR brodifacoum, suggesting that public policies may not be efficient at mitigating risk of exposure for non-target species. Haemorrhage was observed in 88 birds, but AR toxicosis was suspected in only 2 of these individuals, and no difference in frequency of haemorrhage was apparent in birds displaying summed SGAR levels above or below 100 ng/g ww. As for other contaminants, 17.2% of liver samples (11/64) exhibited Pb levels compatible with sub-clinical poisoning (>6 μg/g dw), with 6.3% (4/64) above the threshold for severe/lethal poisoning (>30 μg/g dw). Nine individuals with Pb levels >6 μg/g dw also had AR residues, demonstrating exposure to multiple contaminants. Broad toxicological screening for other contaminants was positive for 18 of 126 individuals, with carbofuran and mevinphos exposure being the suspected cause of death of 17 birds. Our findings demonstrate lower but still substantial AR exposure of scavenging birds compared to predatory birds, and also illustrate the complexity of diagnosing AR toxicosis through forensic investigations.

Portable X-ray fluorescence for bone lead measurements of Australian eagles

Lead (Pb) toxicity from ammunition has been shown to be a threat to scavenging birds across the globe. Toxic levels of lead have recently been found in Australia's largest bird of prey, the wedge-tailed eagle (Aquila audax), through inductively coupled plasma mass spectrometry (ICP-MS) analysis of liver and bone samples. However, ICP-MS is consumptive (causing damage to archived specimens), time-consuming, and expensive. For these reasons, portable X-ray fluorescence (XRF) devices have been optimized to measure bone lead in North American avian species, humans, and other environmental samples. In this study, we assessed portable XRF for bone lead measurement in Australian raptors in two parts. First, we validated the method using tissues from wedge-tailed eagles from Tasmania (A. a. fleayi), analysing bone samples taken from sites on the femur immediately adjacent to sites for which we had ICP-MS data (n = 89). Second, we measured lead via portable XRF in the skulls of wedge-tailed eagles from south-eastern mainland Australia (A. a. audax) collected during a criminal prosecution (n = 92). Portable XRF bone lead measurement demonstrated an excellent correlation with ICP-MS results using root-transformed regression (R² = 0.88). Calculated equivalent ICP-MS values revealed that greater than 50% of the eagles from mainland Australia had elevated lead levels (>10 mg/kg) and 13% had severe lead exposure (>20 mg/kg). Our results support previous studies of North American avian species and suggest that portable XRF could be a useful and inexpensive option for measurement of bone lead in Australian scavenger species.

Increasing incidence of barbiturate intoxication in avian scavengers and mammals in Spain

Pharmaceuticals are considered emerging contaminants in terms of impacts on wildlife. One chemical group of concern is euthanasia agents used in veterinary medicine. Here we present data on the occurrence of barbiturate intoxication using samples collected from 2004 to 2020 of suspected wildlife and domestic animal poisoning cases in Spain (n = 3210). Barbiturate intoxication was seen in 3.4% (45/1334) of the total number of confirmed intoxicated animals. Barbiturates were detected in 0.2% (1/448) of baits containing detectable poisons. The most frequently detected barbiturate was pentobarbital (42/45, 93.3%), but we also detected phenobarbital, barbital, and thiopental (2.2% prevalence for each). Avian scavengers were most frequently affected by barbiturate intoxication (n = 36), especially Eurasian griffon vultures (Gyps fulvus) (n = 28). Median pentobarbital concentrations detected in intoxicated griffon vultures was 27.3 mg kg^-1 in gastric content and 38.1 mg kg^-1 in liver, which highlights the acute effect of the chemical soon after ingestion. At least two large intoxication events affecting griffon vultures were related to the consumption of carcasses from euthanized livestock. We also found phenobarbital in a prepared bait linked to the intoxication of one Eurasian buzzard (Buteo buteo). This study highlights the need for stronger regulation of barbiturates to avoid secondary intoxications due to improper disposal of euthanized livestock.

Lead contamination in tissues of large avian scavengers in south-central Europe

Lead poisoning from spent ammunition is known to affect many avian species. Birds of prey ingest lead when feeding on game shot with lead gunshot or bullets. Raptors with scavenging habits are particularly vulnerable to ingesting lead in areas with intensive hunting and are good indicators of the risk of poisoning from lead ammunition. To assess how much facultative and obligate avian scavengers suffer lead contamination in south-central Europe, between 2005 and 2019 we collected and analysed 595 tissue samples from 252 carcasses of 4 species (golden eagle, bearded vulture, griffon vulture, cinereous vulture). Lead concentrations in organs showed a similar pattern across species with long and small bones revealing the highest median values (5.56 and 6.8 mg/kg w.w., respectively), the brain the lowest (0.12), and the liver and kidney the intermediate (0.47 and 0.284). Overall, 111 individuals (44.0%) had lead concentrations above background thresholds in at least one tissue (i.e. >2 mg/kg w.w. in soft tissues, >8.33 in bone) and 66 (26.2%) had values indicating clinical poisoning (>6 mg/kg w.w. in liver, >4 in kidney, >16.6 in bone). Tissue lead concentrations and incidence of clinical and sub-clinical poisoning were higher in golden eagles and griffon vultures than in bearded and cinereous vultures, likely due to different feeding habits. In all species we found a rapid increase in lead values with age, but differences between age classes were significant only in the golden eagle. Birds with lead fragments in their digestive tract, as detected by X-rays, had higher median lead concentrations, suggesting that hunting ammunition is the main source of lead poisoning. Our results imply that lead impacts the demography of these long-lived species with delayed sexual maturity and low reproduction rate. A rapid transition towards lead-free bullets and gunshot is therefore required across Europe.