Copulatory Behavior of the Egyptian Vulture (Neophron percnopterus) in the Eastern Rhodopes, Bulgaria

Copulatory behavior has been reported in many raptor species, possibly because their copulations are typically conspicuous and frequent. Vultures are single-brooded and long-lived birds in which pair bonds may be maintained from one year to the next. The copulatory behavior was studied in three out of the four vulture species that breed in Europe. However, a more detailed explanation of the exclusive copulatory behavior of the Egyptian vulture regarding the frequency of copulation is missing. Here we provide the first data from the Balkans on the different aspects of the copulatory behavior of the Egyptian vulture and compare it with previous studies on the species and other conspecifics. The study was carried out in the Eastern Rhodopes mountain, Bulgaria, the stronghold of the species in the Balkans. We observed 4 pairs from vantage points and 5 with trail cameras. We recorded 137 copulation attempts in total. The majority of the copulation attempts were successful (86%, n=68) with a mean duration of 17.6±11.8 sec. The daily pattern of copulation frequencies we found suggests a bimodal distribution. Regarding the seasonal pattern of copulation frequencies, two peaks were observed – at the beginning of the breeding season and before the laying. The presence of the male around the female increased with time and before the laying. In terms of conspicuousness, the number of copulation attempts increased with the linear distance from the nests of the observed pairs to the copulation site which was always visible and exposed.