Imperial Eagle Aquila Heliaca Research Articles

Moderate evidence for the sex‐dependent effect of poisoning on adult survival in a long‐lived raptor species

AbstractSurvival rate is usually the greatest contributor to population growth in long‐lived species, and its accurate estimation along with the evaluation of the factors influencing it is therefore essential for effective conservation. Here, we studied the survival of breeding eastern imperial eagles Aquila heliaca in Hungary between 2011 and 2022 and investigated the effect of poisoning, the leading known anthropogenic cause of mortality. We used the Cormack‐Jolly‐Seber mark‐recapture model to estimate annual apparent survival and encounter probabilities based on the capture histories of 208 males and 411 females. We obtained encounter data from the DNA profiles of shed feathers collected at the nest sites, which we also supplemented with presences inferred from parentage analysis. The most supported model estimated a constant 91.6% annual survival over the study period, but models including the effect of sex and poisoning rate on survival had similar support. Sex difference in survival was less than 1% on average, but the survival of males decreased more with poisoning rate than the survival of females. However, due to smaller encounter probabilities, the estimates for males were less precise compared to females. Males may be more at risk from poisoning than females not only due to their more active foraging behaviour during incubation and chick‐rearing but also due to their smaller body size. Apart from providing direct practical information for the conservation management of imperial eagles, our results also highlight the importance of long‐term studies for estimating population parameters of birds of prey.

Birds of Shivapuri Nagarjun National Park, Nepal

Shivapuri Nagarjun National Park harbors diverse avifauna. The last checklist of birds for Shivapuri, published by SNP and BCN (2007), covered 318 species. However, it excluded the Nagarjun Forest birds as this area wasn't incorporated into the national park until 2009. Since then, many new bird sightings have been reported in Shivapuri Nagarjun National Park (SNNP). To address this gap, we've compiled a comprehensive checklist of SNNP birds in Nepal's central mid-hills, drawing on direct observations and a literature review. A total of 396 species of birds belonging to 18 orders and 71 families were known to occur in the park. Order Passeriformes (n=260, 65%) and family Muscicapidae (n=50, 12%) have the highest record of the number of species. Out of 396 bird species, 237 species were recorded during the recent survey of 2021–2022 and 159 species were considered from the past literatures. 10.60% (n=42) of the recorded bird species are classified as nationally threatened according to Nepal’s national red list and 2% (n=8) are listed as globally threatened. The globally threatened birds include Vulnerable greater spotted eagle Aquila clanga, imperial eagle Aquila heliaca, and Kashmir flycatcher Ficedula subrubra; Endangered steppe eagle Aquila nipalensis and Pallas’s fish eagle Haliaeetus leucoryphus; and Critically Endangered white-rumped vulture Gyps bengalensis, slender-billed vulture Gyps tenuirostris and red-headed vulture Sarcogyps calvus. A total of 55 species recorded are included in the CITES Appendices; one species is also listed in the National Parks and Wildlife Conservation Act (NPWCA) Schedule I, and the park includes spiny babbler Acanthoptila nipalensis the only endemic bird of Nepal. Resident species make up the majority (n=243, 61.36%) of birds recorded in the national park. The remaining are the migrants which include summer and winter visitors, passage migrants and vagrants.

Status and Conservation of the Saker Falcon in Austria

The short lecture summarizes the results of a conservation program for the Saker Falcon (Falco cherrug) in Austria for the years 2011–2022. The species reaches the western limit of its global distribution in Austria. Therefore, it is restricted to the east of the country and naturally a scarce species with high conservation concern. When Saker Falcons showed a growing tendency to nest in abandoned corvid nests on high-voltage power lines from the late 1990s on, the Austrian Ornithological Center (AOC, formerly Vetmeduni) and Austrian Power Grid (APG) supported the species from 2007 onward by providing artificial nesting sites on several powerlines within the known breeding range. AOC and BirdLife Austria have been conducting a joint nation-wide conservation program since 2011. This includes a yearly survey of all known breeding sites, ringing Saker chicks (carried out since 2015), and monitoring reasons for mortality and potential threats. Within the surveyed period (2011–2022), the species showed a clear increase in breeding pairs, successfully breeding pairs, and fledged young per breeding attempt. The clearly positive trend in all population parameters surveyed may be attributed to several factors such as nest site availability, nest site selection, and changing weather conditions. The number of artificial nesting sites has been increased; while the conservation program began with the installation of breeding platforms, from 2014 on all additionally installed artificial aids have been nest boxes. Since then, we have observed a steep increase in the number of pairs breeding in these boxes, which most probably contributed to the population growth as well as the rising proportion of successfully breeding pairs. Despite the prospering population, the breeding range of the species has not increased significantly and is still limited to the low-lying Pannonian region in eastern Austria. Contrary to other recovering raptor species in the region (e.g. Imperial Eagle Aquila heliaca and Red Kite Milvus milvus), no clear westward expansion of the Saker’s range could be observed. Rather a rising concentration of pairs in the long-known range led to population growth. Interestingly, the most westerly historic breeding sites on the edge of the Alps and of the Bohemian Massif have been abandoned for decades. The Pannonian basin hosts a single transboundary population of Saker Falcon and the birds move regularly between the different countries. This is also true for the Austrian part of the range: Most recoveries of banded Austrian birds have been made abroad and prove the exchange of birds between Austria, Slovakia, Hungary, and Serbia. Other interesting records of Austrian ringed birds comprise a recovery from Algeria and one from Poland. Currently, we know of no threats impacting the Saker Falcon in Austria on the population level. Nevertheless, our results show some potential threats that must be closely monitored in the future to secure the species. Proven, human-caused mortality reasons comprise collisions with power line infrastructure, wind power plants and vehicles, electrocution, and deliberate shooting. Intentional as well as unintentional poisoning is highly likely to occur at least occasionally but has not yet been investigated thoroughly. Our results give rise to several research topics that should be considered in the future, including the influence of wind power development, possible nest site competition between Eagle Owl (Bubo bubo) or Northern Raven (Corvus corax) and Saker Falcon or the effects of sublethal rodenticide poisoning on the bird’s health and mortality risk.

Some results of field work in the Chelyabinsk region in 2021

We observed birds in the Chelyabinsk region in the spring and summer of 2021. Among others, the rare Imperial Eagle Aquila heliaca, Golden Eagle A. chrysaetos, Turtle Dove Streptopelia turtur, Little Owl Athene noctua and Woodlark Lullula arborea were recorded.

Новые данные о распространении и численности крупных пернатых хищников на Северном Устюрте в границах Атырауской области Казахстана

In May and June 2018 and June 2019 we surveyed breeding populations of large raptors (principally Golden Eagle Aquila chrysaetos, Eastern Imperial Eagle Aquila heliaca, Steppe Eagle Aquila nipalensis, Long-Legged Buzzard Buteo rufinus, Saker Falcon Falco cherrug and Eagle Owl Bubo bubo) in the north-west of the Ustyurt Plateau within the boundaries of the Atyrau Province, Kazakhstan. The area surveyed was ca. 1000 km2 represented the wider area of 3400 km2. Total 12 species of birds of prey were recorded and 8 of them considered as large raptors. Golden Eagle was found nesting on the Donyztau escarpment, 4 breeding territories were recorded and 3 of them successful; nesting density is estimated at about 5.0–6.7 pairs per 100 km of cliffs, the distance between neighboring pairs was ca. 6 km. Imperial Eagle: 5 breeding territories found on the Donyztau and Zheltau escarpments, 4 of them successful; average nesting density is 3.8 pairs per 100 km of cliffs. Steppe Eagle: 14 breeding territories (25 nests) revealed, among them 6 are successful (1–2 nestlings) and on other 3 breeding was failed; average nesting density is estimated at 1.3 pairs per 100 km2. Average distance between neighboring active nests is 2.5 km in Sholkara hill ridge but the distance between successful nests here is much bigger and makes about 13 km. Long-Legged Buzzard: 13 breeding territories (30 nests) found, of which 11 territories were actually occupied and 8 of them had successful breeding. Saker Falcon is found nesting on Donyztau escarpment: 4 breeding territories, including 3 successful; the average nesting density is 6.7 pairs per 100 km of cliffs. Eagle Owl recorded throughout the surveyed area; 11 breeding territories revealed, the average nesting density is 7 breeding territories per 100 km of cliffs and steep slopes. Two other species, Short-toad Eagle and Cinereous Vulture, recorded only occasionally, nesting in the area is not found. In general, our findings demonstrate the area is important for conserving several species of large raptors in the Atyrau Province.

К изучению орла-могильника на Алтае

Приводятся обобщённые сведения по распространению, численности и экологии орла-могильника Aquila heliaca на Алтае. Под Алтаем понимается территория Алтайского края (168 тыс. км2) и Республики Алтай (92,6 тыс. км2), имевшей статус Горно-Алтайской автономной области в составе Алтайского края РСФСР до 1991 г. в нынешних границах. Алтай является одним из немногих российских регионов, где могильник населяет почти все природные зоны, за исключением высокогорий. Популяция вида сокращается в Алтайском крае, но пока ещё находится в относительно благополучном состоянии в Республике Алтай. Гнездовые группировки характеризуется неравномерностью пространственного размещения. Это связано с тяготением могильника к лугово-степным участкам с интенсивной пастбищной нагрузкой.

Movements and landscape use of Eastern Imperial Eagles Aquila heliaca in Central Asia

ABSTRACTCapsule: We describe ecological factors associated with movements of a globally declining raptor species, the Eastern Imperial Eagle Aquila heliaca.Aims: To describe the movements, habitat associations and resource selection of Eastern Imperial Eagles marked in Central Asia.Methods: We used global positioning system (GPS) data sent via satellite telemetry devices deployed on Eastern Imperial Eagles captured in Kazakhstan to calculate distances travelled and to associate habitat and weather variables with eagle locations collected throughout the annual cycle. We also used resource selection models to evaluate habitat use of tracked birds during autumn migration. Separately, we used wing-tagging recovery data to broaden our understanding of wintering locations of eagles.Results: Eagles tagged in Kazakhstan wintered in most countries on the Arabian Peninsula, as well as Iran and India. The adult eagle we tracked travelled more efficiently than did the four pre-adults. During autumn migration, telemetered eagles used a mixture of vegetation types, but during winter and summer, they primarily used bare and sparsely vegetated areas. Finally, telemetered birds used orographic updrafts to subsidize their autumn migration flight, but they relied on thermal updrafts during spring migration.Conclusion: Our study is the first to use GPS telemetry to describe year-round movements and habitat associations of Eastern Imperial Eagles in Central Asia. Our findings provide insight into the ecology of this vulnerable raptor species that can contribute to conservation efforts on its behalf.

Итоги проекта «Оценка влияния воздушных линий электропередачи средней мощности на орнитофауну Мангистауской области (Республика Казахстан)»

The article highlights the project results on the assessment of the impact of middle voltage overhead power lines (PL) on avifauna of Mangistau region of the Republic of Kazakhstan. On repeated examination of 440 km of PL there was determined a fact of death of 123 birds belonging to 29 species. In particular, 23 birds died from injuries because of collision with wires, and 100 birds were electrocuted. Among the latter, about 60 % are eagles (Steppe Eagle Aquila nipalensis, Golden Eagle Aquila chrysaetos, Imperial Eagle Aquila heliaca). There is the dependence of a number of electrocuted birds on the engineering design of PL. There was an extrapolation of the bird electrocution survey results on the whole territory of Mangistau region.

Variation in offspring sex ratio of a long‐lived sexually dimorphic raptor, the Eastern Imperial Eagle Aquila heliaca

Sex ratio theory attempts to explain observed variation in offspring sex ratio at both the population and the brood levels. In the context of low‐fecundity organisms producing high‐investment offspring, the drivers of adaptive variation in sex ratio are incompletely understood. For raptors that display reverse sexual dimorphism (RSD), preferential allocation of resources to the putatively cheaper sex (male) may be a response to environmental, social or demographic stressors. To assess the extent of skew in offspring sex ratios and to evaluate possible dietary, environmental and demographic correlates of such skew to long‐lived RSD avian species, we evaluated the offspring sex ratio of 219 chicks from 119 broods in 30 territories of Eastern Imperial Eagles Aquila heliaca across 7 years and four regions at a nature reserve in Kazakhstan. Only in one region in 1 year of our study did the offspring sex ratio differ significantly from parity (10 males : 1 female in 11 territories). Whereas offspring sex ratios were independent of dietary diversity, precipitation, temperature and productivity, we found that year had a moderate effect on brood sex ratio within territories. Our results provide limited evidence of brood sex manipulation in these populations of Eastern Imperial Eagles, and no mechanistic insight into predictions associated with it. Stochastic variation is likely to explain much of the fluctuation we observed in sex ratios, but our observations are also consistent with the hypothesis that sex‐ratio manipulation may occur irregularly, in concurrence with atypical environmental or demographic conditions that fluctuate at a time scale longer than that of our 7‐year study.

Movements of imperial eagle Aquila heliaca juveniles and description of monitored areas in the border zone between Austria, Hungary and Slovakia

Abstract Five juveniles of the imperial eagle were tracked during 2011-201 2. Movements were monitored in the western part of Slovakia and in the border area between Austria, Hungary and Slovakia. Three eagles came from the Záhorská nížina Lowlands and the others from the Malé Karpaty Mts and the Podunajská nížina Lowlands. Post-fledging movements were recorded in areas around the nests. Post-fledging areas covered a large territory (minimum convex polygons - 89, 941 , 969 km2). During the postfledging period the eagles carried out exploratory flights (1 2-33 km from the nest). One temporary settlement area (TSA) was identified in the border area between Austria, Hungary and Slovakia (minimum convex polygon - 68 km2). Two eagles with radio transmitters were recorded in this area. In the TSA and the post-fledging areas two habitat categories were dominant: arable land and forests. Heterogeneous agricultural areas were also important in the TSA (8%).

Movements of imperial eagle Aquila heliaca juveniles and description of monitored areas in the border zone between Austria, Hungary and Slovakia

Movements of imperial eagle Aquila heliaca juveniles and description of monitored areas in the border zone between Austria, Hungary and Slovakia

Observaciones De Aves Raras En España, 2011

Report on rare birds in Spain 2011. Current report gives details about 452 new records on the presence of 100 rare bird taxa in the whole of Spain. Acceptance index was of 88,94% from a grand total of 579 examined records including pending, duplicated and regional rarities. Details on 12 new taxa for Spain are included for the first time in any rarities report: Asian white-winged scoter Melanitta deglandi, Fea's petrel Pterodroma feae, first and second records, black-bellied storm-petrel Fregetta tropica, eastern imperial eagle Aquila heliaca, sandhill crane Grus canadensis, south polar skua Stercorarius maccormicki, Thayer's Gull Larus thayeri, american hawk-owl Surnia ulula caparoch, buff-bellied pipit Anthus rubescens, eastern black redstart Phoenicurus ochruros phoenicuroides, semicollared flycatcher Ficedula semitorquata and Cretzchsmar's bunting Emberiza caesia. Deserta's petrel, Thayer's gull and hawk owl are new to the Spanish list which was updated in 2012 having considered the rest of the above accepted firsts. The report deals with record numbers of goosander Mergus merganser, buff-breasted sandpiper Tryngites subruficollis and pectoral sandpiper Calidris melanotos besides overwintering episodes of Baird's sandpiper Calidris bairdii and broad-billed sandpiper Limicola falcinellus. Other interesting records are third records for Spain of African white-backed vulture Gyps africanus, upland sandpiper Bartramia longicauda or Baltic gull Larus fuscus fuscus.

An overview of monitoring for raptors in Bulgaria

Abstract Since 1990, nature conservation NGOs are the main players in the running of nation-wide research and monitoring schemes for raptors in Bulgaria. Among them, the Bulgarian Society for the Protection of Birds (BSPB) and Green Balkans are most active, covering the most threatened diurnal raptors in the country. The key species covered by comprehensive monitoring schemes are the Imperial Eagle Aquila heliaca, White-tailed Eagle Haliaeetus albicilla, Egyptian Vulture Neophron percnopterus, Griffon Vulture Gyps fulvus, Black Vulture Aegypius monachus, Saker Falcon Falco cherrug and Red-footed Falcon F. vespertinus. Information on their distribution, numbers, breeding success, productivity, diet, movements etc. is gathered on annual basis. The Buzzard Buteo buteo and Kestrel F. tinnunculus are also regularly monitored at the national level by the Common Bird Monitoring scheme. Distribution of all raptor species has been studied for the purpose of the Atlas of Breeding Birds in Bulgaria. The contemporary satellite telemetry methods revealed important aspects of movements and threats to eagles and vultures from Bulgaria within the country and abroad. Main threats for the raptors in Bulgaria are related to habitat loss, unnatural mortality and disturbance. The main gaps in raptor monitoring in Bulgaria are related to the lack of coverage of most of the diurnal species and owls. There is a strong national and international cooperation in conjunction with the work concerning Imperial Eagle, Egyptian and Griffon Vultures. However, further enhancement of cooperation on other raptor species and issues such as lobbying for implementation of raptor-friendly agricultural practices and enhancement of various economic sectors are needed

Distribution, diet and winter ecology of the Imperial Eagle Aquila heliaca in Jordan

The present study is the first attempt to investigate the diet, seasonality and distribution of the globally vulnerable Imperial Eagle Aquila heliaca in a wintering habitat in Jordan. There was a temporal pattern of observations, with nearly all observations in the northwestern part of the country occurring in late December or January. The main wintering period for Imperial Eagles occurs in January and February where (84.3%) of observations were recorded, peaking in January. Adults predominated, followed by immature birds, with sub-adults being least common. Diet includes 14 identified species of mammals, birds and reptiles. Large domestic animals, most likely consumed as carrion, predominated the food composition of wintering eagles and formed 53.7 % of analyzed food items, followed by presumably live-caught birds (26%) and small and medium sized mammals (19.7%) and reptiles (0.6%) respectively. Trapping was the major threat affecting the Imperial Eagle in its wintering habitat in the eastern desert.

Important Bird Areas in Macedonia: Sites of Global and European Importance

Important Bird Areas in Macedonia: Sites of Global and European Importance

Current Efforts to Monitor and Conserve the Eastern Imperial Eagle Aquila heliaca in Hungary

The globally threatened Eastern Imperial Eagle Aquila heliaca has been one of the flagship species of Hungarian bird conservation efforts since the 1980s. Due to these conservation activities and positive land-use changes during the last 2 decades, the Hungarian Imperial Eagle population increased from as few as approximately 20 pairs in the early 1980s to 81 pairs by 2006. Between 2002 and 2005 as part of a LIFE-Nature project, MME/Birdlife Hungary carried out particularly intensive monitoring, conservation, research, and public awareness actions. The main goal of the project was to secure the long-term sustainable increase in the Imperial Eagle population after Hungary's European Union accession in 2004. New methods were developed and applied to census and monitor the breeding and wintering population sizes. Standardized baseline land-use mapping and surveys were introduced to detect long-term land-use and prey density changes in priority areas for Imperial Eagles and to monitor the effects of key mortality factors, such as electrocution. Historical information and data gathered before and during the project period were assimilated using a Geographic Information System and incorporated into a comprehensive set of Imperial Eagle Management Guidelines.

Spatial structure in the diet of imperial eaglesAquila heliacain Kazakhstan

We evaluated the relationship between spatial variability in prey and food habits of eastern imperial eaglesAquila heliacaat a 90,000 ha national nature reserve in north‐central Kazakhstan. Eagle diet varied greatly within the population and the spatial structure of eagle diet within the population varied according to the scale of measurement. Patterns in dietary response were inconsistent with expectations if either ontogenetic imprinting or competition determined diet choice, but they met expectations if functional response determined diet. Eagles nesting near a high‐density prey resource used that resource almost exclusively. In contrast, in locations with no single high‐density prey species, eagles' diet was more diverse. Our results demonstrate that spatial structuring of diet of vertebrate predators can provide important insight into the mechanisms that drive dietary decisions.

Relationship between demographics and diet specificity of Imperial Eagles Aquila heliaca in Kazakhstan

The demographic consequences of within‐population variability in predator foraging are not well understood. We assessed the relationship between the degree of diet specialization and two demographic parameters, population density and reproductive output, within a single population of Imperial Eagles Aquila heliaca at a nature reserve in north‐central Kazakhstan. Nearest‐neighbour distances between eagle nests throughout the reserve, and thus population density, were correlated with the degree to which diets were specialized. Diet diversity showed an extensive regional variability that was linked to prey distributions, but within‐year analyses of reproductive output did not show similar linkages. However, multi‐year analyses of breeding performance showed inter‐regional differences in nesting success that were paralleled, and probably driven by, similar trends in diet diversity. In contrast, brood size at fledging was not linked to diet diversity and was more probably driven by reserve‐wide influences such as weather. Finally, the decision to initiate breeding was associated neither with diet diversity nor with environmental variability. Our results indicate that the degree of dietary specialization is linked to the demographics of Imperial Eagle populations. For these and other raptor populations, it is possible that management could be used separately to increase or decrease nesting success, brood size at fledging, and the likelihood that a pair will initiate breeding.

Waterbirds in coastal wetlands along the Persian Gulf coast of Iran, January–February 2000

In January and February 2000, about 20 wetland sites were visited to count waterbirds and pay special attention to the presence of Slender-billed Curlews Numenius tenuirostris, a Globally Threatened species. At least 1,200 Eurasian Curlews N. arquata and 240 Whimbrels N. phaeopus were checked individually, but no Slender-billed Curlews were observed. More than 53,000 waterbirds of 82 species were counted during the survey, including Globally Threatened Species like Dalmatian Pelican Pelecanus crispus, Marbled Teal Marmaronetta angustirostris, Ferrugineous Duck Aythya nyroca, White-tailed Eagle Halaeetus albicilla, Greater Spotted Eagle Aquila clanga, and Imperial Eagle Aquila heliaca. Only a small part of the wetlands along the Iranian Gulf coast were counted and a total of over 240,000 waders were estimated to winter in the surveyed wetlands. Our survey suggests that the total Iranian Gulf coast is very important for waterbirds and in particular for waders and Dalmatian Pelican. Apparently suitable habitat for Slender-billed Curlews, including irrigated wheat fields, extensive salt marshes and marshland close to intertidal mudflats, was found in the Hilleh Protected Area (42,600 ha) and Monde Protected Area (46,700 ha), as well as much of the surrounding area up to Bushehr and Monde River Delta.

Migration routes of four juvenile Imperial Eagles Aquila heliaca from the Baikal region of eastern Russia

From 1950 to 1999 there was a substantial decrease in the number of Imperial Eagles Aquila heliaca breeding in the Baikal region of eastern Russia, but there have been no apparent changes in habitat or breeding success within this region. Identification of wintering and stopover sites is therefore necessary to discover whether negative impacts at these sites could be causing the observed population decline. To this end, we satellite-tracked four juvenile Imperial Eagles from Lake Baikal to their wintering grounds. Two sibling eagles were tracked in 1998 and two siblings from a different brood in 1999. The eagles migrated through eastern Mongolia and central Inner Mongolia (China), and wintered from south China to Thailand. Siblings independently used the same migration flyway, and the flyway was different between families. These results provide useful information for determining the causes of the decline in the population of Imperial Eagles in the Baikal region.