Northern Goshawk Accipiter Gentilis Research Articles

Prey preferences and recent changes in diet of a breeding population of the Northern Goshawk Accipiter gentilis in Southwestern Europe

ABSTRACTCapsule: Northern Goshawk Accipiter gentilis diet has changed significantly since the 1980s, probably due to changes in populations of preferred prey species.Aims and methods: To assess changes to the breeding season diet of the Northern Goshawk in southwest Europe over three decades. We examined prey remains at and around nests and assessed avian prey availability using point count and line transect surveys.Results: During 2008–11, Goshawks mainly ate birds, with Feral Pigeons Columba livia f. domestica being the most important prey species. Goshawks preferred prey of 100−400 g and forest prey species to non-forest species. Goshawk diet has changed significantly over recent decades: 22% of current prey items belong to species that were not part of the diet in the 1980s. We suggest that these dietary changes reflect changes in the abundance of prey species of the preferred size caused by changes in land use leading to an increase in forest cover, new prey species colonization and changes in the abundance and management of domestic prey.Conclusion: This study emphasizes that major transformations occurring in agroforestry systems are affecting the main preferred prey of important forest predators, which may have consequences for conservation of both the predators and their prey.

Density‐dependent increase in superpredation linked to food limitation in a recovering population of northern goshawks Accipiter gentilis

A better understanding of the mechanisms driving superpredation, the killing of smaller mesopredators by larger apex predators, is important because of the crucial role superpredation can play in structuring communities and because it often involves species of conservation concern. Here we document how the extent of superpredation has changed over time, and assessed the impact of such temporal variation on local mesopredator populations using 40 yr of dietary data collected from a recovering population of northern goshawks Accipiter gentilis, an archetypical avian superpredator. We then assessed which mechanisms were driving variation in superpredation, e.g. was it opportunistic, a response to food becoming limited (due to declines in preferred prey) or to reduce competition. Raptors comprised 8% of goshawk diet on average in years when goshawk abundance was high, which is higher than reported elsewhere. Additionally, there was a per capita increase in superpredation as goshawks recovered, with the proportion of goshawk diet comprising raptors increasing from 2 to 8% as the number of goshawk home‐ranges increased from ≤ 14 to ≥ 25. This increase in superpredation coincided with a population decline in the most commonly killed mesopredator, the Eurasian kestrel Falco tinnunculus, which may represent the reversal of the ‘mesopredator release’ process (i.e. mesopredator suppression) which occurred after goshawks and other large raptors declined or were extirpated. Food limitation was the most likely driver of superpredation in this system given: 1) the substantial decline of two main prey groups in goshawk diet, the increase in diet diversity and decrease in goshawk reproductive success are all consistent with the goshawk population becoming food‐limited; 2) it's unlikely to be purely opportunistic as the increase in superpredation did not reflect changes in the availability of mesopredator species; and 3) the majority of mesopredators killed by goshawks do not compete with goshawks for food or nest sites.

Female turnover rate differs between two Northern GoshawkAccipiter gentilisnesting areas, as revealed by DNA analysis of moulted feathers

The turnover rate of breeding Northern Goshawk Accipiter gentilis females in two study areas in southern Norway, which are assumed to experience different levels of illegal human persecution, was estimated using DNA extracted from moulted feathers, along with other characteristics. Female turnover rate over a 4-year period for each nesting territory during 1990–2015 was significantly higher in Aust-Agder County (31.9%; 23 territories), where hunters have long shown antipathy to Goshawks, than in Telemark County (17.3%; 25 territories). Turnover rate was not related to territory quality. The proportion of successful nesting attempts was lower in Aust-Agder (70–75%) than in Telemark (82–84%), but for newly built nests, which are less likely to be known by hunters, the difference was not significant (77.4 vs 79.6%). The proportion of juvenile female Goshawks among recruits and in the total breeding population also did not differ between the two areas. Our findings support the notion that Goshawk persecution was higher in Aust-Agder than in Telemark. We found that the use of phenotypic characteristics for individual recognition was successful in 96.2% of 130 comparisons of female Goshawks from two consecutive nesting attempts, when assessed using genetic markers.

Apparent survival, territory turnover and site fidelity rates in Northern Goshawk Accipiter gentilis populations close to the northern range limit

ABSTRACTCapsule: Mark–recapture data suggest low apparent survival and sex- and population-specific site fidelity and territory turnover in adult Northern Goshawks Accipiter gentilis breeding in northern Europe.Aims: To understand how species cope with global environmental change requires knowledge of variation in population demographic rates, especially from populations close to the species’ northern range limit and from keystone species such as raptors. We analyse apparent survival and breeding dispersal propensity of adult Northern Goshawks breeding in northern Europe.Methods: We used long-term mark–recapture data from two populations in Finland, northern Europe, and Cormack–Jolly–Seber models and binomial generalized linear models to investigate sex- and population-specific variation in apparent survival, territory turnover and site fidelity.Results: We report low apparent survival (53–72%) of breeding adult Goshawks. Breeding dispersal propensity was higher in females than males, especially in northern Finland, contrasting with previous studies that suggest high site fidelity in both sexes.Conclusion: Low apparent survival in females may be mainly due to permanent emigration outside the study areas, whereas in males the survival rate may truly be low. Both demographic aspects may be driven by the combination of sex-specific roles related to breeding and difficult environmental conditions prevailing in northern latitudes during the non-breeding season.

Development of Novel Microsatellite Markers for the Northern Goshawk (Accipiter Gentilis) and their Utility in Cross-Species Amplification

The Northern Goshawk ( Accipiter gentilis) is a large forest raptor with a Holarctic distribution and, in some portions of its range, a species of conservation concern. To augment previously reported genetic markers, 13 novel polymorphic microsatellite markers were developed to establish individual identification and familial relationships, to assess levels of genetic diversity, and to identify diagnostic markers. Of the 22 loci tested, 13 were polymorphic, seven were monomorphic, and two failed to amplify. This suite of microsatellite loci yielded a combined probability of parental exclusion of 98%; a single individual sampled from a North American population can be reliably identified using a combination of seven of the 13 polymorphic loci. Cross-species screening in Cooper's Hawks (A. cooperii) and Sharp-shinned Hawks (A. striatus) of the 20 loci that successfully amplified in Northern Goshawks identified 13 loci as polymorphic in each species. Six of these loci (Age1303, Age1308, Age1309, Age1312, and Age1314) appeared to be useful in distinguishing between Accipiter species. These markers will be useful to researchers investigating populations of North American accipiters.

Intraguild predation leads to cascading effects on habitat choice, behaviour and reproductive performance.

Intraguild predation (IGP) is a commonly recognized mechanism influencing the community structure of predators, but the complex interactions are notoriously difficult to disentangle. The mesopredator suppression hypothesis predicts that a superpredator may either simultaneously repress two mesopredators, restrain the dominant one and thereby release the subdominant mesopredator, or elicit different responses by both mesopredators. We show the outcome arising from such conditions in a three-level predator assemblage (Eurasian eagle owl Bubo bubo L., northern goshawk Accipiter gentilis L. and common buzzard Buteo buteo L.) studied over 25years. In the second half of the study period, the eagle owl re-colonized the study area, thereby providing a natural experiment of superpredator introduction. We combined this set-up with detailed GIS analysis of habitat use and a field experiment simulating intrusion by the superpredator into territories of the subdominant mesopredator, the buzzard. Although population trends were positive for all three species in the assemblage, the proportion of failed breeding attempts increased significantly in both mesopredators after the superpredator re-colonized the area. We predicted that superpredator-induced niche shifts in the dominant mesopredator may facilitate mesopredator coexistence in superpredator-free refugia. We found significant changes in nesting habitat choice in goshawk, but not in buzzard. Since competition for enemy-free refugia and the rapid increase in population density may have constrained niche shifts of the subdominant mesopredator, we further predicted behavioural changes in response to the superpredator. The field experiment indeed showed a significant increase in aggressive response of buzzards towards eagle owl territory intrusion over the course of 10years, probably due to phenotypic plasticity in the response towards superpredation risk. Overall, our results show that intraguild predation can be a powerful force of behavioural change, simultaneously influencing habitat use and aggressiveness in predator communities. These changes might help to buffer mesopredator populations against the negative effects of intraguild predation.

Intraguild predation and competition impacts on a subordinate predator.

Intraguild (IG) predation and interspecific competition may affect the settlement and success of species in their habitats. Using data on forest-dwelling hawks from Finland, we addressed the impact of an IG predator, the northern goshawk Accipiter gentilis (goshawk), on the breeding of an IG prey, the common buzzard Buteo buteo. We hypothesized that the subordinate common buzzard avoids breeding in the proximity of goshawks and that interspecific competitors, mainly Strix owls, may also disturb common buzzards by competing for nests and food. Our results show that common buzzards more frequently occupied territories with a low IG predation threat and with no interspecific competitors. We also observed that common buzzards avoided territories with high levels of grouse, the main food of goshawks, possibly due to a risk of IG predation since abundant grouse can attract goshawks. High levels of small rodents attracted interspecific competitors to common buzzard territories and created a situation where there was not only an abundance of food but also an abundance of competitors for the food. These results suggest interplay between top-down and bottom-up processes which influence the interactions between avian predator species. We conclude that the common buzzard needs to balance the risks of IG predation and interference competition with the availability of its own resources. The presence of other predators associated with high food levels may impede a subordinate predator taking full advantage of the available food. Based on our results, it appears that interspecific interactions with dominant predators have the potential to influence the distribution pattern of subordinate predators.

Spatial assessment of the potential risk of avian influenza A virus infection in three raptor species in Japan.

Avian influenza A, a highly pathogenic avian influenza, is a lethal infection in certain species of wild birds, including some endangered species. Raptors are susceptible to avian influenza, and spatial risk assessment of such species may be valuable for conservation planning. We used the maximum entropy approach to generate potential distribution models of three raptor species from presence-only data for the mountain hawk-eagle Nisaetus nipalensis, northern goshawk Accipiter gentilis and peregrine falcon Falco peregrinus, surveyed during the winter from 1996 to 2001. These potential distribution maps for raptors were superimposed on avian influenza A risk maps of Japan, created from data on incidence of the virus in wild birds throughout Japan from October 2010 to March 2011. The avian influenza A risk map for the mountain hawk-eagle showed that most regions of Japan had a low risk for avian influenza A. In contrast, the maps for the northern goshawk and peregrine falcon showed that their high-risk areas were distributed on the plains along the Sea of Japan and Pacific coast. We recommend enhanced surveillance for each raptor species in high-risk areas and immediate establishment of inspection systems. At the same time, ecological risk assessments that determine factors, such as the composition of prey species, and differential sensitivity of avian influenza A virus between bird species should provide multifaceted insights into the total risk assessment of endangered species.

Genetic markers validate using the natural phenotypic characteristics of shed feathers to identify individual northern goshawks Accipiter gentilis

The recognition of individual animals is essential for many types of ecological research, as it enables estimates of demographic parameters such as population size, survival and reproductive rates. A popular method of visually identifying individuals uses natural variations in spot, stripe or scar markings. Although several studies have assessed the accuracy of these methods in mammals, crustaceans and fish, there have been few attempts to determine whether phenotypic characteristics are accurate when used for birds. Furthermore, even less is known about whether shed or moulted body parts can be reliably used to visually identify individuals. Here we assessed the accuracy of using phenotypic characteristics to identify avian individuals using a double‐marking experiment, whereby nine microsatellite genetic markers and natural markings on shed feathers were used to independently identify northern goshawks Accipiter gentilis. Phenotypic and genetic identification of individuals was consistent in 94.4% (51/54) comparisons. Our results suggest that the phenotypic characteristics of shed feathers can be reliably used as a non‐invasive and relatively inexpensive technique to monitor populations of an elusive species, the northern goshawk, without having to physically re‐capture or re‐sight individuals. We posit that using natural markings on shed feathers will also be a reliable method of identifying individuals in avian species with similar phenotypic characteristics, such as other Accipiter species.

Habitat and weather requirements of diurnal raptors wintering in river valleys

AbstractThe winter raptor community was studied in river valleys of North Eastern Poland during the winters of 2000- 2010. Via transect counts method we showed the potential drivers of raptor abundance, and co-occurrence patterns. We analysed the influence of weather and habitat factors along on the single species abundance and diversity of the raptor assemblage. We found that higher temperatures corresponded with higher occurrence of the common buzzard Buteo buteo, rough-legged buzzard Buteo lagopus, Eurasian sparrowhawk Accipiter nisus, hen harrier Circus cyaneus and lower of the common kestrel Falco tinnunculus. When considering the effect of each habitat variable on the whole raptor assemblage, the relative proportion of urban areas to pasture had the most distinct effect on species abundance and diversity. Most of species were found to be less abundant in areas with a high proportion of urban areas, while some, like the Eurasian sparrowhawk and the northern goshawk Accipiter gentilis, occurred more often on such areas. We observed that the difference in the number of these species could be explained mainly by the different habitat requirements due to individual food preferences and flexibility of migration strategies

Lifespan Analyses of Forest Raptor Nests: Patterns of Creation, Persistence and Reuse

Structural elements for breeding such as nests are key resources for the conservation of bird populations. This is especially true when structural elements require a specific and restricted habitat, or if the construction of nests is costly in time and energy. The availability of nesting-platforms is influenced by nest creation and persistence. In a Mediterranean forest in southeastern Spain, nesting-platforms are the only structural element for three forest-dwelling raptor species: booted eagle Aquila pennata, common buzzard Buteo buteo and northern goshawk Accipiter gentilis. From 1998 to 2013, we tracked the fate of 157 nesting-platforms built and reused by these species with the aim of determining the rates of creation and destruction of nesting-platforms, estimating nest persistence by applying two survival analyses, describing the pattern of nest reuse and testing the effects of nest use on breeding success. Nest creation and destruction rates were low (0.14 and 0.05, respectively). Using Kaplan Meier survival estimates and Cox proportional-hazards regression models we found that median nest longevity was 12 years and that this was not significantly affected by nest characteristics, nest-tree dimensions, nest-builder species, or frequency of use of the platform. We also estimated a transition matrix, considering the different stages of nest occupation (vacant or occupied by one of the focal species), to obtain the fundamental matrix and the average life expectancies of nests, which varied from 17.9 to 19.7 years. Eighty six percent of nests were used in at least one breeding attempt, 67.5% were reused and 17.8% were successively occupied by at least two of the study species. The frequency of nest use had no significant effects on the breeding success of any species. We conclude that nesting-platforms constitute an important resource for forest raptors and that their longevity is sufficiently high to allow their reuse in multiple breeding attempts.

Spatial application of a predictive wildlife occurrence model to assess alternative forest management scenarios in northern Arizona

Wildlife species of conservation concern can present forest managers with a particular challenge when habitat needs appear to be in contrast with other management objectives, particularly fuel reduction to reduce wildfire risk. Proposed actions can be opposed by stakeholders, delaying management activities until a resolution is met. In the southwestern USA, the primary goal of forest management is to reduce the risk of severe wildfire through forest restoration treatments. The USDA Forest Service has designated the northern goshawk (Accipiter gentilis) a management indicator species in this region. However, it has been difficult to achieve a common understanding of goshawk habitat needs among forest stakeholders. We combined two separate and complementary modeling approaches – a statistically based occurrence model and alternative forest treatment models – to yield predictions about forest management effects on the goshawk in ponderosa pine-dominated forests (Pinus ponderosa) on the Kaibab Plateau, Arizona. Forest treatment models were developed based on USDA Forest Service recommendations for goshawk habitat and post-treatment data from ecological restoration experiments, both of which were also components of forest treatment guidance from the Kaibab Forest Health Focus collaborative planning effort. All treatment alternatives resulted in a 22–26% reduction in estimated goshawk occurrence, but the declines were not uniform across the study area, varied by forest type, and were not as large as the effects of recent and severe wildfire (44% reduction in occurrence). Considering the controversial history of forest management with respect to the goshawk, it is prudent to interpret results from this study in the context of tradeoffs between wildfire risk reduction and wildlife habitat quality that can be effectively evaluated through science-based collaborative assessment and planning. While developed for a specific, high-profile species in the southwestern USA, the approach is applicable to many other species whose occurrence has been monitored over multiple years.

Raptors as surrogates of biodiversity along a landscape gradient

Summary With biodiversity facing threats, there is a need to improve reserve selection procedures. However, detailed information about different biodiversity measures (e.g. species richness) at potential sites is often lacking, and selecting areas that protect most biodiversity is difficult. To simplify matters, biodiversity surrogate species, that is, species associated with higher biodiversity than average, have been used for area selection. However, consensus about the performance of the surrogate species concept is lacking, and there are few studies investigating potential differences in the effectiveness of multiple predators as surrogates for biodiversity over large spatial scales. We evaluated two avian predators, the northern goshawk Accipiter gentilis and the Ural owl Strix uralensis, as surrogates for biodiversity in the boreal forest biome in Western Finland. We used a study design including nest sites and two reference sites for each nest, the diversity of birds and wood‐decaying fungi (polypores). We assessed simultaneously whether surrogacy persisted at the landscape level while moving from one vegetation zone to another. We generally found more birds and polypores around the nest sites for both goshawks and Ural owls than at their respective reference sites. However, the goshawk outperformed the Ural owl. Additionally, although biodiversity was found to decrease at the landscape scale as a result of a decrease in vegetation complexity with increasing longitude, the surrogacy efficiency of the raptors remained unchanged. Synthesis and applications. These findings suggest that the surrogate species concept applied to raptors may be an efficient addition to methods for identifying areas of conservation priority, even across vegetation zones. We conclude that protecting areas around raptor nests is a method to consider in order to halt forest biodiversity loss. Finally, sampling biodiversity along diversity and landscape gradients can improve the necessary assessment of surrogate species.

Antiparasite treatments reduce humoral immunity and impact oxidative status in raptor nestlings

Parasites are natural stressors that may have multiple negative effects on their host as they usurp energy and nutrients and may lead to costly immune responses that may cause oxidative stress. At early stages, animals may be more sensitive to infectious organisms because of their rapid growth and partly immature immune system. The objective of this study was to explore effects of parasites by treating chicks of two raptor species (northern goshawk Accipiter gentilis and white-tailed sea eagle Haliaeetus albicilla) against both endoparasites (internal parasites) and ectoparasites (external parasites). Nests were either treated against ectoparasites by spraying with pyrethrin or left unsprayed as control nests. Within each nest, chicks were randomly orally treated with either an antihelminthic medication (fenbendazole) or sterile water as control treatment. We investigated treatment effects on plasma (1) total antioxidant capacity TAC (an index of nonenzymatic circulating antioxidant defenses), (2) total oxidant status TOS (a measure of plasmatic oxidants), and (3) immunoglobulin levels (a measure of humoral immune function). Treatment against ectoparasites led to a reduction in circulating immunoglobulin plasma levels in male chicks. TOS was higher when not receiving any parasite reduction treatment and when receiving both endo- and ectoparasitic reduction treatment compared with receiving only one treatment. TAC was higher in all treatment groups, when compared to controls. Despite the relatively low sample size, this experimental study suggests complex but similar relationships between treatment groups and oxidative status and immunoglobulin levels in two raptor species.

Hunting behaviour and breeding performance of northern goshawks Accipiter gentilis, in relation to resource availability, sex, age and morphology

Animal territories that differ in the availability of food resources will require (all other things being equal) different levels of effort for successful reproduction. As a consequence, breeding performance may become most strongly dependent on factors that affect individual foraging where resources are poor. We investigated potential links between foraging behaviour, reproductive performance and morphology in a goshawk Accipiter gentilis population, which experienced markedly different resource levels in two different parts of the study area (rabbit-rich vs. rabbit-poor areas). Our analyses revealed (1) that rabbit abundance positively affected male reproductive output; (2) that age, size and rabbit abundance (during winter) positively affected different components of female reproductive output; (3) that foraging movements were inversely affected by rabbit abundance for both sexes (for females, this may mainly have reflected poor provisioning by males in the rabbit-poor area); (4) that younger breeders (both in males and females) tended to move over larger distances than older individuals (which may have reflected both a lack of hunting experience and mate searching); and (5) that male body size (wing length) showed some covariation with resource conditions (suggesting possible adaptations to hunting agile avian prey in the rabbit-poor area). Although we are unable to establish firm causal relationships with our observational data set, our results provide an example of how territory quality (here, food abundance) and individual features (here, age and morphology) may combine to shape a predator's foraging behaviour and, ultimately, its breeding performance.

An updated checklist of birds of Sariska Tiger Reserve, Rajasthan, India

Surveys were carried out at 10 sites in the buffer and core zones of Sariska Tiger Reserve during 2007-2011. MacKinnon species listing method was used to compile a checklist of birds. A total of 224 bird species was recorded including 36 new records. Ashy Drongo Dicrurus leucophaeus, Marshall Iora Aegithina nigrolutea, Eurasian Eagle Owl Bubo bubo, Brown-headed Barbet Megalaima zeylanica, Indian Nightjar Caprimulgus asiaticus, Long-legged Buzzard Buteo rufinus, Northern Goshawk Accipiter gentilis, Red-necked Falcon Falco chicquera, Pheasant-tailed Jacana Hydrophasianus chirurgus, Red-whiskered Bulbul Pycnonotus jocosus, White-capped Water Redstart Chaimarrornis leucocephalus were some new records. Some important observations are given in detail.

Honey Buzzard Pernis apivorus nest‐site selection in relation to habitat and the distribution of Goshawks Accipiter gentilis

The selection of a suitable nest‐site is critical for successful reproduction. Species' preferences for nest‐sites have presumably evolved in relation to local habitat resources and/or interactions with other species. The importance of these two components in the nest‐site selection of the Eurasian Honey Buzzard Pernis apivorus was assessed in two study areas in eastern Austria. There was almost no difference in macro‐ and micro‐habitat features between nest‐sites and random plots, suggesting that Honey Buzzards did not base their choice of nest‐site on habitat characteristics. However, nests were placed significantly further from nests of Northern Goshawk Accipiter gentilis than would be expected if nest‐sites had been chosen at random. Furthermore, in one study area Honey Buzzards appeared to favour areas close to human settlements, perhaps indicating a mechanism to avoid Goshawks, which tend to avoid the proximity of humans. No habitat variable was significantly associated with the loss of Honey Buzzard young, but predation was higher in territories closer to breeding pairs of Goshawks at both study sites. Although Honey Buzzards are restricted to nesting in forests, their choice of nest‐site therefore appears to be largely dictated by the distribution of predators. Studies of habitat association may yield misleading results if the effects of predation risk on distribution are not considered.

Evaluation of artificial nests as a conservation tool for three forest-dwelling raptors

Forest age structure has become younger and the amount of old forest has decreased due to intensive forestry in Northern Europe. Consequently, large forest-dwelling hawks may lack nest sites as they need large trees to support their nests. Construction of artificial nests has been a globally adopted conservation measure to provide nest sites for several raptors, but the impact of this practice has seldom been evaluated. We compared the nesting success of northern goshawk Accipiter gentilis, common buzzard Buteo buteo, and honey buzzard Pernis apivorus in natural and artificial nests based on long-term data in Finland. The probability of successful nesting of goshawk and common buzzard was lower in artificial nests, whereas no difference was found in the nesting success of honey buzzard between the nest types. Brood size did not differ between natural and artificial nests in successful nests of any of the three species. Finally, distances to anthropogenic features had no effect on nesting success. These results indicate that hawks switching from natural to artificial nests are potentially lured to an ecological trap with higher risk of nesting failure. However, breeding at artificial nests, even with lower success than in natural nests, can still add to the population, if otherwise nonbreeding individuals settle to nest. It should be investigated which part of the population breeds in artificial nests and whether the site selection for artificial nests needs revision. Our results emphasize the importance of monitoring and evaluation of well-intentioned conservation efforts.

Plumage Aberration in Northern GoshawkAccipiter gentilis

The subspecies of Northern Goshawk Accipiter gentilis present clinal plumage variation. However, aberrant plumages are exceptional. On 2 February 2012, in Sedziszow (southern Poland), a dead Northern Goshawk with aberrant plumage was found. The bird was mostly beige but had retained the banding pattern in the flight feathers and streaking on the breast and underwing coverts. Birds in the described aberrant plumage might be confused with the Eastern Palearctic subspecies A. g. albidus.

Molecular identification of traces from the White-tailed Sea Eagle

Over the preceeding decades, after periods of dramatic decline and extinction in many parts of Europe, the White-tailed Sea Eagle (Haliaeetus albicilla) has re-colonized traditional breeding areas. However, this large apex predator remains threatened, not only by the bioaccumulation of environmental pollutants, but also by targeted poisoning and poaching. In connection with a forensic case, a novel PCR assay was developed for the sensitive and specific detection of sea eagle DNA traces in questioned samples of unknown origin. The assay amplifies a fragment of the popular phylogenetic marker gene cytochrome b. Primers were designed to bind sites with relatively high variability between homologous sequences from H. albicilla and other related European birds of prey. Assay sensitivity was sufficient for single cell analysis. Specificity was tested in vitro and the primers did not cross-detect DNA from humans, chicken and the following raptors: Common Buzzard (Buteo buteo), Northern Goshawk (Accipiter gentilis), Red Kite (Milvus milvus) and Black Kite (Milvus migrans). Applicability for the analysis of poor quality samples was demonstrated with extracts from field-collected small molted down feathers that did not contain detectable amounts of sea eagle nuclear DNA. Amplicons of the expected size were generated, purified and sequenced. Sequence data were subjected to Basic Local Alignment Search Tool analysis and affiliated with cytochrome b from H. albicilla. The novel PCR primers allowed for the correct assignment of traces from H. albicilla, even in mixed samples and in cases with limited and degraded biological material.