Expedition for the Egyptian vulture in Asia Minor [ 2009-09-24 11:34:10 ]

 

During 12-19.09.2009 BSPB/BirdLife Bulgaria team in collaboration with Doga Dernegi/BirdLife Turkey conducted expedition in Asia Minor aiming research of the migration ecology of the Egyptian vulture focused on the threatening factors for the species during migration along its autumn flyway over Turkey.
The expedition was initiated as a result of the fast and large-scale decline of the species and the urgent need to discover the threats outside of the breeding grounds, which are probably significantly responsible for the worsening of the population status.

The aims of the expedition were:
• To gather additional information for the factors threatening the Egyptian vulture during the period of autumn migration on the territory of Central Asia Minor.
• To develop methodology for fast evaluation of the species population in Western and Central Asia Minor.

Implemented activities:
• Search for stopover sites along the migration way.
• Assessment of the health status of the observed birds.
• Search for the roosting sites of the species and counts of the roosting birds.
• Counting of the autumn migration in the supposed peak migration period of the Egyptian vulture in the region of Belen pass (bottleneck raptor migration site near Iskenderun bay, South Turkey).

Results:
• On 13.09.2009 was observed congregation of 123 Egyptian vultures on a dump site in the region of Ankara (the initial data for the locality of the site was kindly provided by colleagues from Doga Dernegi). The age structure of 105 of the birds was recorded: 71 adults (6 and more years old), 12 first plumage (juveniles), 4 second plumage, 7 third plumage, 3 fourth plumage, 8 fifth plumage. Six days later (19.09) most of the birds were moved and in the region were present 33 birds. In 2008 and 2009 BSPB ringed 52 juvenile Egyptian vultures, but no ringed birds were observed on the dumping site. According to data from the colleagues from Doga Dernegi, the dump site holds high numbers of birds also during the breeding season, with maximum of 121 vultures observed in July 2009 (B. Sen, pers. comm.). The site probably attracts breeding and non-breeding birds in radius of minimum 50 km around and serves as communal congregation area in the breeding season, pre-migration gathering site in August-september and stopover site during the migration.
• On the dumping site the Egyptian vultures were observed feeding exclusively with slaughter houses offal, which most probably represent their main food there.
• There were not observed birds showing signs of weakness and indications of poisoning or health problems.
• 10 more dumping sites were visited, mainly in the surroundings of Belen pas and Iskenderun bay, but nowhere were any Egyptian vultures observed, and also surprisingly low numbers of Ravens, Crows, Jackdaws and Magpies.
• I the region of Belen pass in 4 consecutive days (15-18.09.2009) for totally 15 hours of observations was conducted count of the autumn migration of the birds. There were recorded 1330 storks and 1037 migrating raptors from 17 species including 28 Egyptian vultures.
• The roost site of only one migrating Egyptian vulture was found. The bird was observed for about 40 minutes before sunset in search of roost site in a forested mountainous area 59 km northeast of Iskenderun bay. The vulture was flying over high voltage power line and after long inspection of the different pylons and several consecutive attempts for perching, finally perched on safe part of one the pylon. On the observed congregation of vultures on the dumping site only 28 birds among which all recorded juveniles, stayed for roost in the close surroundings of the dump site (26 on cliffs and 2 on safe pylons of electricity transmission line).
• There was observed one Egyptian vulture in third plumage with wrapped about 30 sm long strong nylon string around its left leg. The bird was observed tripping over in the string and even felling down. In flight the bird was vigorously attacked by several Ravens , which even often pecked its flight feathers, and caused it to land down. On the ground the Ravens also attacked it, but the vulture succeeded to drive them back and was giving an impression of bird in good health condition.
• There was observed behavior in the Egyptian vulture, which to our knowledge is not described in the literature: a bird in third plumage (about three years old) was begging food from an adult probably not breeding bird. The birds were perched one next to another and the younger staying in typical begging posture, consecutively more than 20 times with short breaks weakly was pecking the tip of the bill of the adult. The adult stayed passive and immovable and did not showed signs of agonistic behavior. Taking into account of the clear white plumage of the adult, its bright yellow face without black dots, probably it have been a bird recently obtained adult plumage and still not breeding.
• In Taurus Mountain was found Griffon vulture colony to our knowledge not described in the literature. The colony was estimated at minimum 10 pairs.
• Discovered were a breeding territory and a nest of the extinct from Bulgaria Bearded vulture, occupied most probably of polyandric trio of adult birds (two males and one female). Poluandry in the Bearded vulture is not uncommon in the Pyrenees, where up to 13,5% of the territories are occupied by trios, but till now to our knowledge it is not documented in Turkey.

Conclusions:
• In the current good knowledge of the number of the Egyptian vulture population on the Balkans, the simultaneous count of the migration of the species on the bottleneck sites in South Turkey can be used for evaluation of the current population in Western and Central Asia Minor.
• Highly needed is additional and wider-scale research of the Egyptian vulture along its migration route and in the wintering areas in Africa in order to clearly grade the importance of the different limiting factors.


3-years old Egyption vulture begging food from an adult one
3-years old Egyption vulture begging food from an adult one
The rock with the Griffon Vulture colony Migration study point at Iskenderun
The rock with the Griffon Vulture colony Migration study point at Iskenderun
39 Egyptian Vultures over the dump
39 Egyptian Vultures over the dump