In recent years, the northern goshawk (Accipiter gentilis) has colonized suburban and urban areas in Berlin, Germany, and elsewhere in Europe. Because of the high proportion of feral pigeons (Columba livia f. domestica) in their diet, urban goshawks are suspected to have a high infection rate with Trichomonas gallinae. Therefore, from 1998 to 2001, we examined 269 nestlings from 90 nests for infection with T. gallinae by culture of swabs taken from the oropharynx and checked their oropharynx for the presence of caseous lesions indicative of trichomonosis. In 80% of the nest sites (nϭ90), at least one nestling was infected. The nestling infection rate with T. gallinae was 69.7% (nϭ33) in 1998, 73.0% (nϭ89) in 1999, 55.8% (nϭ77) in 2000, and 62.9% (nϭ70) in 2001. In total, 65.1% of the northern goshawk nestlings were culture positive for T. gallinae. Prevalence increased with the age of nestlings ( 2 ϭ12.4, nϭ269, dfϭ5, Pϭ0.03) and tended to increase with brood size ( 2 ϭ9.345, nϭ269, dfϭ4, Pϭ0.053). Caseous lesions were present in 12 nestlings (4.5%), but only 10 of these were culture positive for T. gallinae. Two nestlings (0.7%) had large caseous lesions (diameterϾ1 cm) characteristic of late-stage trichomonosis and died shortly after examination. It is suggested that the combination of a high prevalence of T. gallinae with a low rate of pathologicic changes is the result of an evolutionaryadapted parasite-host relationship.

Residues of the potentially toxic metals lead, mercury, and cadmium were analyzed in liver and kidney tissue of 61 free-ranging white-tailed eagles (Haliaeetus albicilla) found dead or moribund in Germany and Austria between 1993 and 2000. Highest values and the widest range were detected for lead in liver and for mercury in kidney tissue. Lead concentrations considered to induce lethal lead poisoning (>5 ppm wet wt) were determined in 28% of liver samples. Lead fragments were detected it the gizzards of two specimens, presumably having died from lead intoxication. Histopathological findings in a recently dead white-tailed eagle indicating acute lead exposure comprise degenerative Purkinje cells in the cerebrellum and inclusion bodies in renal tubular cells. Mercury residues in organs are decreasing compared to former studies in periods when organomercury compounds were used as seed dressing. All cadmium values were low or are at background levels in white-tailed eagles. The present study clearly identities lead as a toxic metal poison in white-tailed eagles in Germany and Austria.

We analysed 123 white-tailed sea eagles (Haliaeetus albicilla) from (primarily central) Europe with respect to variability and differentiation based on 499 bp of the mitochondrial control region and genotypes at seven unlinked nuclear microsatellites. Variability was high (overall expected heterozygosity, haplotype and nucleotide diversity being 0.70, 0.764 and 0.00698, respectively) and both marker systems showed a subdivision into two main genetic clusters (microsatellites) or haplogroups (mtDNA). In line with earlier analyses focusing on populations from northern and eastern Europe, as well as from Asia, we found a high level of admixture in Europe and no signs of a bottleneck -despite a severe decline of white-tailed sea eagle populations during the 20 th century. Europe is thus a global stronghold for this species not only with respect to the number of breeding pairs but also regarding the proportion of species-wide genetic diversity. Our dense sampling revealed a possibly clinal variation within central Europe from north-west to south-east that was reflected by the distribution of mtDNA haplotypes as well as the two microsatellite-based clusters. This population differentiation in central Europe probably originated from a geographically structured postglacial colonization and was later enhanced by recent demographic fluctuations.

Eleven white-tailed sea eagles (WSEs) (Haliaeetus albicilla) collected in Finland between 1994 and 2001 were examined for their causes of death, including analyses of ubiquitous environmental contaminants and parasites. Four WSEs died due to electrocution. Two were lead poisoned and another had fragments of a lead bullet in its gizzard. An 11-year-old female drowned entangled in fishing gear, but also had mercury levels in its liver and kidneys known for detrimental physiological effects. One WSE was evidently killed by an intraspecific conflict, which was also assumed to be with another bird. The mortality factors of two WSEs could not be clarified, but one had a lead level of 4.604 microg g(-1) in its liver, indicating high lead exposure at a clinically relevant concentration. All organ levels of chlorinated pesticides, polychlorinated biphenyls, and cadmium were moderate and not harmful for birds of prey. Seven helminth species, but no ectoparasites or coccidians, were found in 8 of 10 WSEs investigated for parasites. The highest prevalence of 40% was found for the liver fluke Metorchis billis, but no severe parasitosis was diagnosed for the eagles. The two acanthocephalan species Corynosoma semerme and Polymorphus meyeri are both new records for WSEs.

The northern goshawk (Accipiter gentilis) is a top predator in the terrestrial food web of large parts of the Holarctic. Due to its sedentary nature and well-investigated feeding ecology, it represents the most suitable bird of prey species in continental Europe for monitoring environmental pollutants. We analyzed the levels of organochlorine pesticides, polychlorinated biphenyls (PCB), and nonessential heavy metals in organ samples of 62 free-ranging northern goshawks found dead or injured in Germany from 1995 to 2001. Our results indicate significant differences in the contaminant burden of northern goshawks between three regions in Germany. Presumably, these differences were caused by different application periods and legislative restrictions before the German reunion, especially for the use of DDT in agriculture and forestry. Extraordinarily high residues of PCBs and DDE, the main metabolite of DDT, were found mainly in livers of northern goshawks inhabiting Berlin. Body condition is highly negatively correlated with the contamination level of the individual, especially for the persistent and lipophilic organochlorines and for mercury. PCB concentrations in hepatic tissue increase rapidly with age, and birds in their first summer had significantly lower levels than birds in their first winter or older. Adult female northern goshawks from Berlin had significantly higher hepatic concentrations of most of the higher-chlorinated PCBs and of cadmium than males from the same region. Cadmium residues were in general higher in renal tissue than in hepatic tissue, and cadmium levels in kidneys increased with age. Lead concentrations indicative of acute lead poisoning were detected in one bird and suggested in two others. All other heavy metal concentrations were low and represent background levels for birds of prey in Germany.

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Twelve white-tailed sea eagles (Haliaeetus albicilla groenlandicus) found dead between 1997 and 2000 in Greenland were examined to investigate the health status, including the causes of death and the burden of organochlorine contaminants and potentially toxic heavy metals. The determined causes of death were unspecific trauma (n = 6), lead poisoning (n = 2) with 36 and 26 ppm lead in the liver tissue, infectious diseases (n = 1), injuries sustained during intraspecific conflict (n = 1), and gunshot (n = 1). One lead poisoned eagle had a single lead shot pellet in its gizzard. No diagnosis could be made in one case because of decomposition of the carcass. Four of the investigated eagles were injured with lead shot or bullet fragments; one of the birds was killed with about 69 lead shots. Levels of organochlorine pesticides, polychlorinated biphenyls, mercury, and cadmium in organs were moderate. The parasite fauna consisted of one coccidian and three helminth species. The acanthocephalas Profiliocollis botulus and Corynosoma suduche as well as the nematode Stegophorus stellaepolaris are all new records for the white-tailed sea eagle.

By 2040, roughly two-thirds of humanity are expected to live in urban areas. As cities expand, humans irreversibly transform natural ecosystems, creating both opportunities and challenges for wildlife. Here, we investigate how the Northern Goshawk ( Accipiter gentilis ) is adjusting to urban environments. We measured a variety of behavioural and ecological parameters in three urban and four rural study sites. City life appeared related to all parameters we measured. Urban female goshawks were overall 21.7 (CI 95% 5.13–130) times more likely to defend their nestlings from humans than rural females. Urban goshawks were 3.64 (CI 95% 2.05–6.66) times more likely to feed on pigeons and had diets exhibiting lower overall species richness and diversity. Urban females laid eggs 12.5 (CI 95% 7.12–17.4) days earlier than rural individuals and were 2.22 (CI 95% 0.984–4.73) times more likely to produce a brood of more than three nestlings. Nonetheless, urban goshawks suffered more from infections with the parasite Trichomonas gallinae , which was the second most common cause of mortality (14.6%), after collisions with windows (33.1%). In conclusion, although city life is associated with significant risks, goshawks appear to thrive in some urban environments, most likely as a result of high local availability of profitable pigeon prey. We conclude that the Northern Goshawk can be classified as an urban exploiter in parts of its distribution.