A paper [1] about Greater Spotted Eagle and their hybrids with Lesser Spotted Eagle has been published. The ranging areas at breeding and wintering grounds have been studied for birds in Poland and Estonia. Results are based on 26 individuals (including 11 hybrids) monitored 2008 to 2022.
Individual ranging areas at both breeding and wintering grounds become smaller as the birds mature. As Greater Spotted Eagle becomes older they arrive earlier at breeding sites. Moreover, immature eagles extend their stay at breeding areas. Some birds begin to limit their ranging areas starting their 4th or 5th calendar year, while others continue to move across wide ranges by their 7th year.
For males a philopatry phenomenon could be observed. They visited nests of existing pairs within their natal population prior to their own involvement in breeding. Immature individuals were first observed at nests between their 3rd and 7th calendar years, but confirmed breeding typically occurred later between their 8th and 10th calendar years.
No behavioral differences have been noticed between Greater Spotted Eagle and their hybrids. It was proven that both Greater Spotted Eagle and their hybrids exhibit the slow maturation and prolonged preparation for breeding.
This study is a continuation of earlier work, which was also published as an article [2]. 28 Greater Spotted Eagles from populations in Estonia, Poland and Belarus were studied. The birds migrated to Africa, Europe and Asia. The birds wintered in wetlands, of which 15 out of 29 were legally protected. One-third of the individuals wintering in Europe stayed in the same national park in Greece. Only two locations in Africa were protected.
The behaviour and migration patterns of the hybrid Greater Spotted Eagle (Aquila clanga) and Lesser Spotted Eagle (Aquila pomarina) after fledging, tracked by satellite telemetry, can also be read in another article [3].
[1] Grzegorz Maciorowski, Michał Polakowski, Ülo Väli, Artur Golawski, Paweł Mirski, GPS tracking reveals range size and movement patterns in immature eagles (Clanga clanga and C. clanga x pomarina) with delayed maturation, Ornithology, Volume 143, Issue 1, January 2026, Pages 1–10, doi
[2] Ülo Väli, Valery Dombrovski, Grzegorz Maciorowski, Urmas Sellis, Adham Ashton-But, Spatial and temporal differences in migration strategies among endangered European Greater Spotted Eagles Clanga clanga. Bird Conservation International. 2023;33:e6. doi
[3] Bernd-U. Meyburg, Christiane Meyburg, Post-fledging Behavior and Outward Migration of a Hybrid Greater × Lesser Spotted Eagle (Aquila clanga × A. pomarina), Journal of Raptor Research, 41(2), 165-170, (1 June 2007)