Distribution, abundance, breeding parameters, threats and prey preferences of the eastern imperial eagle (Aquila heliaca) in European Turkey

Abstract

Abstract During the period 2008-201 3, 32 different breeding territories were occupied by eastern imperial eagles (EIEs). These territories were mainly distributed in two regions: the Dervent Heights/Yıldız Mts. and the area to the north of the Marmara sea coast. The nearest neighbour distance established was 4.2 km. The mean distance between pairs was 1 0.44±2.95 km. The mean value of breeding success for the period 2008-201 3, including 1 07 cases of incubation, was 1 .01±0.1 0. The mean breeding success of birds in the Marmara region (1 .05±0.78) was higher than that in the Dervent Heights/Yıldız Mts. (0.91±0.84). The present study on the diet of the EIE was based on the remains of 582 prey items of at least 70 taxa. Mammals were the most common group (46.5%), followed by birds (32.4%) and reptiles (20.3%). The white-breasted hedgehog (Erinaceus roumanicus) was the most common prey, followed by two tortoises - Hermann's tortoise (Eurotestudo hermanni) and the Greek tortoise (Testudo graeca) - which together accounted for a total of 1 4.4% of the prey caught. The prey species particularly represented in the food spectrum of the studied pairs were: the yellow-legged gull (Larus michahellis), the European souslik (Spermophilus citellus), the chicken (Gallus gallus f. domestica) and the white stork (Ciconia ciconia). These species together accounted for 67.8% of the prey caught. There was a statistically significant difference (Z=2.52, p=0.01 ) in the food preferences of the EIEs in the two studied regions. Abstrakt V období 2008-201 3 bolo orlami královskými obsadených 32 rôznych hniezdnych teritórií. Tieto územia sa nachádzajú najmä v dvoch oblastiach: pohorie Derventa/Yıldız a územie na sever od Marmarského mora. Najbližšia vzdialenost medzi hniezdiskami bola 4,2 km. Stredná vzdialenost medzi pármi bola 1 0,44 ± 2,95 km. Priemerná hodnota hniezdnej úspešnosti v období 2008-201 3 vrátane 1 07 prípadov inkubácii bola 1 ,01±0,1 0. Priemerná hniezdna úspešnost vtákov v Marmarskom regióne (1 ,05±0,78) bola vyššia ako v oblasti pohorí Derventa/Yıldız (0,91±0,84). Predkladaná štúdia potravy orla královského bola založená na 582 zvyškoch koristi, obsahujúcej minimálne 70 taxónov. Cicavce boli najrozšírenejšie skupinou (46.5 %), nasledované vtákmi (32,4 %) a plazmi (20,3 %). Najcastejšou koristou bol jež bledý (Erinaceus roumanicus) a dva druhy korytnaciek - korytnacka zelenkastá (Eurotestudo hermanni) a korytnacka grécka (Testudo graeca), ktoré dohromady predstavovali celkom 1 4,4 % z ulovenej koristi. Potravné spektrum sledovaných párov obsahoval tieto druhy koristi: cajka žltonohá (Larus michahellis), sysel pasienkový (Spermophilus citellus), domáca sliepka (Gallus gallus f. domestica) a bocian biely (Ciconia ciconia). Tieto druhy dohromady tvorili 67,8 % z ulovenej koristi. Bol preukázaný štatisticky významný rozdiel (Z=2,52, p=0,01 ) v preferencii potravy orlov královských v oboch študovaných oblastiach.