Productivity and Diet of Lesser Spotted Eagle ( Aquila Pomarina ) in Lithuania in 2001–2003

Bergmanis²,

Väli

2017

Ibis

Self Cite

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.

“…10–90%) of the pairs in a local population may not raise any fledglings in a given year (Meyburg et al . , Lõhmus & Väli , Treinys & Dementavičius , Bergmanis et al . ).…”

mentioning

confidence: 99%

Strong territoriality and weak density‐dependent reproduction in Lesser Spotted Eagles Clanga pomarina

Bergmanis²,

Väli

2017

Ibis

Self Cite

“…Osprey and Whitetailed Eagle prey on similar fish species (e.g., Drobelis 2004;Tuvi and Väli 2007), whereas Black Stork, though it also preys mainly on fish , takes fish of different species (mainly Rutilus rutilus and Alburnus alburnus; authors data). Amphibians constitute a significant part of both Lesser Spotted Eagle and Black Stork diet (Treinys and Dementavičius 2004;). The diet similarities of two species groups (i. e., White-tailed Eagle-Osprey and Lesser Spotted Eagle-Black Stork) correspond to the nesting habitat overlap too (see Fig.…”

Section: Discussionmentioning

confidence: 99%

“…The first breeding pairs in Lithuania were found in 1987, and latest figures suggest the breeding population to be ∼90 pairs (Dementavičius 2007). White-tailed Eagles prey mainly on fish and waterfowl (Cramp and Simmons 1980), but is known to kill other raptors (Dementavičius 2004;Helander 1983;Mikkola 1983). The Lesser Spotted Eagle is a migratory species with a body mass of ∼1.1-2.2 kg (Cramp and Simmons 1980).…”

Section: Introductionmentioning

confidence: 98%

Coexistence of protected avian predators: does a recovering population of White-tailed Eagle threaten to exclude other avian predators?

Dementavičius

Mozgeris³

et al. 2011

Eur J Wildl Res

Self Cite

The processes of competition and predation determine the degree to which species can coexist; the importance of competition in particular has been emphasized at high trophic levels. Competition exclusion will occur when habitat overlap between sympatric species is high. In this study, we investigated nesting habitat overlap between internationally protected diurnal tree-nesting avian predators of central Europe, namely, White-tailed Eagle (Haliaeetus albicilla), Lesser Spotted Eagle (Aquila pomarina), Black Stork (Ciconia nigra), and Osprey (Pandion haliaetus). We found significantly different nesting habitats among the study species and suggest that this could be a consequence of the resource-based segregation, but not a consequence of asymmetrical interspecific competition. The results also show that habitat of the recovering populations of White-tailed Eagle overlapped with the habitat used by the Lesser Spotted Eagle, Black Stork, and Osprey to varying extents with a niche overlap values being below the competition exclusion threshold. Nevertheless, we suggest that competition by White-tailed Eagle at a population level may limit Osprey, though not Lesser Spotted Eagle or Black Stork.

“…Transition to the market economy and restoration of private land property during the recent 15 years have brought about dramatic changes in the national forest and agriculture sector, which might have affected the population of Lesser Spotted Eagle. No changes in the species productivity were recorded during the study period, except those in nest-site selection and foraging habits (Treinys & Dementavièius 2004;Treinys & Mozgeris 2006). The lack of coordinated and nationwide monitoring did not allow to evaluate the actual population trend.…”

Section: Introductionmentioning

confidence: 99%

“…At present, Lesser Spotted Eagle still remains one of the most abundant birds of prey distributed in all regions of the country (Drobelis 2004). The estimates of the population for 19942001 changed from 300500 to 9001,200 pairs (Treinys & Dementavièius 2004). Recent studies (20012005) suggest that 1,5001,800 pairs breed in Lithuania (Treinys 2005).…”

Section: Introductionmentioning

confidence: 99%

CHANGES IN THE ABUNDANCE OF THE LESSER SPOTTED EAGLE (AQUILA POMARINA) BREEDING POPULATION IN LITHUANIA IN 1980–2006

Acta Zoologica Lituanica

Drobelis²,

Šablevičius³

et al. 2007

Self Cite

Abstract. In the mid-20 century, Lesser Spotted Eagle (Aquila pomarina) was considered to be one of the most abundant species among the birds of prey in the forests of Lithuania. The estimates of the national population changed from 300500 to 1,5001,800 pairs in 1994 and 2005, respectively. Changes in the population estimates did not reflect the actual population trend, but rather the level of investigation of the species in the country. In reality, the current status of the species population is unknown due to the lack of regular, nationwide monitoring. The aim of this work was to estimate the status of the Lesser Spotted Eagle population in Lithuania. Field studies in 10 sample plots in various regions of Lithuania during the period 20032006 showed that the number of breeding pairs declined by 31% on average as compared to the period 19801998. We suggest that the population of Lesser Spotted Eagle decreased by 26% across the country during the period 19802006. Possible reasons of such decline are discussed in this study.