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The globally threatened imperial eagle reaches the southern and southwestern border of its distribution in Asia Minor, however, there had been scanty data available regarding the local breeding population until recently.
Although sporadic data of nesting and eagle observations in the 20th century were published in the literature, experts were aware of only three cases of proven nesting in Anatolia, so the possibility of the local population being on the verge of extinction could not be excluded. Surveys carried out with Hungarian coordination in the past five years fortunately confirmed the opposite.
In 1998, MME organized the 4th Imperial Eagle Symposium in Csillebérc, where the species specialists could hear about the Turkish imperial eagles for the first time. Mehmet Gursan, who wrote his dissertation on the species, presented those three known imperial eagle nesting habitats, and estimated the breeding population around 35-70 pairs. In the next ten years, we did not hear any new information about the Turkish population, which was still considered to be small, since Turkish conservationists did not carry out targeted surveys and even checking known territories was unresolved.
In 2007, MME’s volunteers prepared an expedition to Georgia for the purpose of surveying imperial eagles in the country. On the way to Georgia, they visited three sites in Turkey, from where Bulgarian and Turkish colleagues had earlier observations of the species. Fortunately, two sites yielded imperial eagle observations and a few more possible territories were taking shape within those two days. Based on these promising signs, during conversations with Bulgarian (BSPB) and Turkish (Doga Dernegi) Birdlife partner organizations we proposed to initiate targeted imperial eagle surveys in Turkey. Within the framework of a joint Life project running from 2009 through 2013, MME started expeditions in Anatolia while BSPB in Thrace (European part of Turkey) in collaboration with Turkish experts.
During five years, we executed two trips to the inner parts of Anatolia to Bolu, Ankara, Eskisehir, Corum and Cankiri regions. Main aim of the spring studies (late March-early April) was to locate nest sites, which were checked back during summer expeditions (late June-early July) to collect data on breeding success, diet and threatening factors. Usually, one MME worker and three experienced volunteers participated in an expedition using a 4x4 truck of MME. As a result of 10 expeditions, we found 50 territories, of which 47 were unknown to Turkish conservationists before. Altogether, we found about 100 active or formerly active nests, thereby data on Anatolian imperial eagles have been multiplied.
Satellite tagged eagles provide wealth of information to scientists and
conservationists regarding the species (Source: satellitetracking.eu).
The species nests mainly on black and Scots pine at 700-1400 m above sea level. Their distribution primarily follows the pine forest-steppe line. Based on our diet studies, it seems that eagles may adopt two different feeding strategies. Wherever the eagle density is high, strong populations of prey species such as susliks or mole-rats also exist similarly to the situation found in eastern steppes. Nevertheless, eagles also feed on semi-wild poultry, as well as mole-rats and hedgehogs, but we also found 15 other prey species ranging from the marbled polecat to the white stork.
Furthermore, we found eagles in habitat where natural prey was scarce, but high numbers of illegal dumps maintained by local poultry farms existed providing easy meal for the pairs. These illegal dumps provided food for not only imperial eagles, but also to several other endangered species at European level such as the Egyptian, black and griffon vulture. Despite all this, authorities have been trying to eliminate these with varying degree of success referring to hazards to human and animal health. It is clear that one of the most urgent and hardest task of Turkish nature conservation will be getting an agreement over the maintenance of legal and controlled waste dumps in the future.
Nowadays, Turkey has been showing incredibly fast infrastructural development, expansion of towns, settlements and factories, building of roads and electric lines and vast open pit mines, all of which pose serious threat to natural habitats, and by which we have already experienced lower breeding success and nest site desertion despite the time period of our study being quite short. At present, number of grazing livestock is still significant compared to that of Central-Europe, however, Turkish colleagues have already reported about certain level of decrease in animal numbers, which would cause degradation of grazing lands in the long run. Despite worrying signs, populations of raptors still seem to be numerous and healthy, and local experts need to continue the surveys and conservation work in collaboration with foreign experts in the future more intensively.
Parallel to the surveys conducted by Hungarians, Bulgarian colleagues identified 40 imperial eagle territories in Thrace proving that the small Bulgarian population, totalling about 20 pairs, is virtually the extension of that, consequently, it may be in connection with distant populations in the Caucasus region and even more eastern steppe populations through that. The currently known 90 pairs do not allow proper estimate for the whole country, but based on what we know from the expeditions the number of breeding population high likely hovers around a few hundred pairs. Therefore, Turkey probably hosts the third largest imperial eagle population after Russia and Kazakhstan. Due to the fast infrastructural development and the small area covered by expeditions yet, today Turkey is the most important target in the world in relation to the conservation of the species.
The expeditions were carried out in part by BSPB’s “Save the raptors” Life Nature project (www.saveraptors.org), as a contract between MME, RSPB and Doga Dernegi, in which Jose Tavares (RSPB), Süreyya Isfendiyaroglu (Doga Dernegi), Svetoslav Spasov, Dimitar Demerdzhiev and Stoycho Stoychev (BSPB) helped a lot. Rest of the expeditions’ budget was covered by the participants (number of expeditions in parenthesis): Attila Bereczky (1), István Béres (5), Iván Demeter (2), Dobromir Dobrev (1), Szabolcs Farkas (1), Márton Horváth (8), Tibor Juhász (3), Róbert Kazi (2), Antal Klébert (1), András Kleszó (3), András Kovács (3), László Kozma (1), László Losonczi (1), Bertalan Majercsák (1), Gábor Papp (3), László Pénzes (1), Nándor Seres (2), Balázs Szelényi (1), Tamás Szitta (3).
Satellite tagging also helped to discover habitats of the species
Between 2009 and 2013, 25 young imperial eagles were fitted with satellite transmitters in Bulgaria by the associates of BSPB. The fixes have provided a wealth of new and indispensable information to conservationists regarding the migration routes and wandering habits of the species. One of the most important information was that almost all Bulgarian eagles visited the Turkish eagle habitats and spent the winter there, during which a few birds also perished unfortunately. It is obvious that the conservation of the Bulgarian population is impossible without knowing threatening factors in Turkey and mitigating them. Besides Bulgarian eagles, one Hungarian and one Macedonian eagles also wandered as south as Turkey, where they met their fate. Satellite data clearly show that despite vast suitable habitats, wide variety of sources of danger is present in the country, which affects not only local populations but also all other European and Asian populations migrate through it.
Hybridisation of eagle species
It has been proved recently that individuals of different raptor species may pair up and even breed successfully. The closely related spotted and lesser spotted eagles form a hybridisation zone in Poland the Baltic States. However, it has been suspected only in a few occasions in other eagle species, mainly based on plumage characters of immature eagles. During one of MME’s expeditions, we could reveal a rare case, when a female imperial eagle mated with a phenotypically steppe eagle-looking male and they reared chicks in at least two years. The currently known closest breeding pairs of steppe eagles located 200 km from here. Genetic samples taken from the feathers of the chicks and parents and the preliminary results surprisingly showed the male steppe eagle being an F1 hybrid already, therefore their chicks were F2 generation hybrids. This interesting discovery encourages experts to carry out further studies since in the one hand there might be an unknown Anatolian steppe eagle population, in the other hand the hybridisation of the two species may be more frequent then it was thought before.
Márton Horváth