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Characterizing the genetic diversity and structure of populations is essential for understanding their evolutionary history and planning species conservation. The lesser spotted eagle (Clanga pomarina) is a large migratory raptor with a relatively small breeding range concentrated in Eastern Europe. We evaluated the level of genetic diversity and population structuring by estimating the length diversity of 23 microsatellite markers in 306 individuals and sequencing 473 nucleotides from the mitochondrial pseudo-control region in 265 individuals across the distribution range. The microsatellite data suggested shallow differentiation between geographical regions and moderate genetic diversity across the range; no recent population bottlenecks were detected. Mitochondrial diversity was relatively low; however, high values were recorded at the southern edge of the distribution range. This, in combination with the star-like distribution of mitochondrial haplotypes, suggests the expansion of the European population from a single (Balkan) refugium during the late Pleistocene or early Holocene after the glacial population bottleneck. However, the Caucasian population may have survived in a separate refugium. We conclude that the lack of clear population structuring and ongoing gene flow across Europe support the treatment of the geographically restricted global population of the lesser spotted eagle as a single evolutionary and conservation unit.

Forest-dwelling raptors nest in the same close, mature forest stands over many years. As mature stands are targets for timber harvesting, the conservation of nest sites should be integrated into commercial forestry practices. Ecological data supporting conservation decisions are essential for ensuring effective conservation, and minimising costs and conflicts among different stakeholders. Here, we analysed nest site selection and nest site turnover patterns in a typical mature-forest-dwelling raptor in the core area of its global population. Our aim was to provide a basis for nesting habitat conservation in the context of commercial forestry. The lesser spotted eagle Clanga pomarina was found to prefer mature stands, located close to the forest’s edge, for nesting. Pine stands were largely avoided by nesting pairs, but the composition of other tree species was similar to stands located in surrounding forests. The lesser spotted eagle occupied the nest for an average of three years, and the number of used nests within a territory increased progressively with the longevity of its occupation. Within a territory, the pair moved between alternate nests mostly up to 600 m. The results of this study suggest that long-term conservation approaches for mature-forest-dwelling raptors should use breeding territory, which contains several nest sites (or suitable stands) spaced at certain distances and covered by temporal buffer, as a target unit in conservation-supporting forestry practices.

The ontogeny of migration routines used by wild birds remains unresolved. Here we investigated the migratory orientation of juvenile lesser spotted eagles (LSE; Clanga pomarina) based on translocation and satellite tracking. Between 2004 and 2016, 85 second-hatched juveniles (Abels) were reared in captivity for release into the declining German population, including 50 birds that were translocated 940 km from Latvia. In 2009, we tracked 12 translocated juveniles, as well as eight native juveniles and nine native adults, to determine how inexperienced birds come to use strategic migration routes. Native juveniles departed around the same time as the adults and six of eight used the eastern flyway around the Mediterranean, which was used by all adults. In contrast, translocated juveniles departed on average 6 days before native LSEs, and five travelled southward and died in the central Mediterranean region. Consequently, fewer translocated juveniles (4/12) than native juveniles (7/8) reached Africa. We conclude that juvenile LSEs have a much better chance of learning the strategic southeastern flyway if they leave at an appropriate time to connect with experienced elders upon departure. It is not clear why translocated juveniles departed so early. Regardless, by the end of the year, most juveniles had perished, whether they were translocated (10/12) or not (6/8). The small number of surviving translocated juveniles thus still represents a significant increase in the annual productivity of the German LSE population in 2009., Highlighted Article: In 2009, most juvenile eagles translocated from Latvia to Germany departed earlier than native juveniles and adults, and consequently failed to learn the species' traditional eastern detour around the Mediterranean.

We assessed whether populations of the migratory, philopatric, territorial Lesser Spotted Eagle Clanga pomarina are regulated through territoriality and density-dependent reproduction rates. In the north-western part of the distribution to the east of the Baltic Sea, territories were spaced regularly and consistently between years. We did not find strong support for an improvement of reproductive output with an increase in distance to the nearest neighbour or with a decrease of the number of conspecifics within a 2-km radius around nest sites. Eagles differed greatly in territory spacing across three studied geographical areas, but breeding performance did not follow the same pattern. Performance of birds at the northern limit of their distribution did not differ from that in an adjacent southern area. Moreover, breeding performance fluctuated synchronously across different geographical areas, perhaps indicating climatic spatial autocorrelation or trophic interactions with synchronous vole population fluctuations over large areas. Our data suggest population regulation through territoriality, but do not identify density-dependent breeding performance in this internationally-protected raptor. Population density may be a good criterion for the selection of priority sites for conservation, but synchronous fluctuations in reproductive success over large geographical areas suggest that habitat conservation should similarly be focused at large scales. This article is protected by copyright. All rights reserved.

Hybridization is a significant threat for endangered species and could potentially even lead to their extinction. This concern applies to the globally vulnerable Greater Spotted Eagle Aquila clanga ...

The Lesser Spotted Eagle belongs to a species with obligatory cainism, which means that in the natural state it is rare that two young eagles fledge, although as a rule two chick’s hatch. The breeding population in Germany is at the western edge of the species’ range and is declining (a 23% decrease between 1993 and 2007). Local extinction can be anticipated and therefore nestling management has been implemented in the German federal state of Brandenburg since 2004 as a conservation measure by using human intervention to prevent the death of the younger sibling. This is in addition to other methods such as nest-site protection, habitat preservation, legislation etc. Furthermore, in 2007, second hatched eagle chicks (Abels) from Latvia were translocated for the first time. The managed pairs (nests physically inspected) were on average more successful than the unmanaged pairs (nests not physically inspected). It cannot be determined as to whether the inspection of the nests had a negative effect on breeding. Breeding success of the pairs present in Brandenburg, including non-breeders, increased by 57 % in 2007 due to nestling management, and that of the managed pairs alone by 67 %. In 2007 the behaviour of six young eagles was studied using satellite telemetry. This study determined that the Abels migrated as well as the first hatched eagle chicks (Cains), and that their survival chances were equally good. The Abels imported from Latvia migrated in two out of three cases along the same route as the German Lesser Spotted Eagles to the Bosporus. One Latvian Abel which fledged in Germany was tracked by satellite to Zambia where many Lesser Spotted Eagles winter. A German Abel wintered North of the Equator in the Sudan and neighbouring countries for over six months and started its return migration on 27 April 2008. Abstrakt: Orol krikľavý je druh s pravidelným kainizmom, co v prirodzených podmienkach sposobuje len výnimocne vyletenie dvoch mlaďat napriek vyliahnutiu dvoch mlaďat zo znasky. Hniezdiaca populacia v Nemecku sa nachadza na zapadnom okraji arealu druhu a jej veľkosť klesa (23% pokles v obdobi 1993–2007). Je možne ocakavať lokalne vyhynutie, preto sa od roku 2004 v Nemeckej spolkovej republike Brandenbursko použiva ako prostriedok ochrany hniezdny manažment. Predstavuje ľudsku intervenciu s cieľom zabraniť smrti mladsieho surodenca spolocne s ďalsimi metodami napr. ochrana hniezdisk a habitatov, legislativa atď. V roku 2007 sa prvýkrat premiestnili z Lotysska druhe vyliahnute mlaďata (Abelovia). Manažovane hniezda (s priamou kontrolou) boli priemerne uspesnejsie ako hniezda bez manažmentu (priamej kontroly). Negativny vply kontrol hniezd na hniezdnu uspesnosť nebol rozhodujuci. Hniezdna uspesnosť parov vyskytujucich sa v Brandenbursku, zahŕňajuc aj nehniezdiace jedince, vzrastla kvoli hniezdnemu manažmentu na 57 % v roku 2007, pri manažovaných paroch samotných na 67 %. V roku 2007 sa studovalo satelitnou telemetriou spravanie sa siestich mladých orlov. Studia ukazala, že Abelovia migrovali aspoň tak ako prve vyliahnute orlicata (Kainovia) a ich sance na prežitie boli rovnako dobre. Abelovia privezeni z Lotysska migrovali k Bosporu v dvoch z troch pripadov po rovnakých trasach ako nemecke orly krikľave. Jeden lotysský Abel, ktorý vyletel v Nemecku, bol sledovaný satelitom do Zambie, kde zimuje veľa orlov krikľavých. Nemecký Abel zimoval severne od rovnika v Sudane a v okolitých krajinach viac ako sesť mesiacov pricom zacal migraciu spať 27. aprila 2008.

Greater and lesser spotted eagles (Aquila clanga, A. pomarina) are two closely related forest eagles overlapping in breeding range in east-central Europe. In recent years a number of mixed pairs have been observed, some of which fledged hybrid young. Here we use mitochondrial (control region) DNA sequences and AFLP markers to estimate genetic differentiation and possible gene flow between these species. In a sample of 83 individuals (61 pomarina, 20 clanga, 2 F1-hybrids) we found 30 mitochondrial haplotypes which, in a phylogenetic network, formed two distinct clusters differing on average by 3.0% sequence divergence. The two species were significantly differentiated both at the mitochondrial and nuclear (AFLP) genetic level. However, five individuals with pomarina phenotype possessed clanga-type mtDNA, suggesting occasional gene flow. Surprisingly, AFLP markers indicated that these “mismatched” birds (originating from Germany, E Poland and Latvia) were genetically intermediate between the samples of individuals in which mtDNA haplotype and phenotype agreed. This indicates that mismatched birds were either F1 or recent back-cross hybrids. Mitochondrial introgression was asymmetrical (no pomarina haplotype found in clanga so far), which may be due to assortative mating by size. Gene flow of nuclear markers was estimated to be about ten times stronger than for mtDNA, indicating a sex-bias in hybrid fertility in accordance with Haldane’s rule. Hybridization between the two species may be more frequent and may occur much further west than hitherto assumed. This is supported by the recent discovery of a mixed pair producing at least one fledgling in NE Germany.