Tönn, the famous Spotted Eagle, is again overwintering in El Hondo (Alicante), eastern Spain. Tönn has been monitored aided by satellite tracking since 2008 from its breeding grounds in Estonia. Although its transmitter stopped some years ago, the bird is still holding it over its back – so it is still easy to identify – and since then returns every autumn to winter in El Hondo.
Interestingly, Tönn is actually a hybrid between a Lesser Spotted Eagle Aquila pomarina (father) and Greater Spotted Eagle Aquila clanga (mother). Both species are very close genetically and interbreeding is not rare along the hybrid zone, being a significant threat for the globally endangered Greater Spotted Eagle (more info here).
Genetic analyses and its external traits show that Tönn is more similar to its mother, therefore Tönn has been considered to be a putative Greater Spotted Eagle.
Additionaly, another presume adult Greater Spotted Eagle and a second-winter have been observed in the area this winter. Hence, this location is one of the most important sites in Spain for wintering Greater Spotted Eagles.
Other important sites in Spain for the species in winter include Ebro Delta, Doñana and the Strait of Gibraltar. For the latest site, this winter has been exceptionally good, especially for Lesser spotted eagles, recording over 10 different individuals and other hybrids including a tracked bird from Lithuania that even crossed The Strait in late November. Interestingly, in the winter 2014, other juvenil raised by the same pair, performed a more easterly migration route, crossing the Bosphorus and arriving to Kenya.
If you want to get more info, check Birding the Strait´s excellent post here.