Mortality cases among the Egyptian vultures [ 2011-08-25 13:48:13 ]

 

During the months April and May the Egyptian vultures’ breeding season was promising to be more successful than the last year. From 32 known pairs, 24 have started incubation, which is with two pairs more than the previous year. Every year due to different reasons some pairs do not succeed in hatching their eggs and part of the juveniles die after hatching. On average two breeding pairs (the ones which laid eggs) are not successful each year, and this year their number reached five. Two pairs did not have success in the incubating of the eggs and the juveniles of three other pairs died.

At least two of the pairs were unsuccessful because of the death of one of the adult birds – one during the incubation, the other during the chick rearing period, which was at least 50 days old and was found dead too. The reasons for the failure of the three other pairs are unknown till now. For one of them, a pair of ravens could be the reason for the death of the juvenile, which perished at about 10-20 days age. The nest of the ravens was only at about 10 meters from the vultures’ nest. Being more maneuverable, the Ravens have advantage in the air conflicts and use every case to attack the vultures. Possibly they may had killed the juvenile, when the parents were not in the nest.

Hard times had the Egyptian vultures in the Nature park “Rusenksi Lom”, where one pair broke the national record for latest egg laying. There are only two pairs left in the area and in the middle of April the adult male from the older and more experienced pair disappeared. We suppose that the bird have been poisoned after eating from illegally set poison for carnivores. Georgi Georgiev – the biodiversity expert from the Nature park has found poisoned jackals, stray and domestic dogs and even an adult Goshawk (Accipiter gentilis). The crime is still not convicted because of lack of interest of the responsible state authorities. The female bird which remained alone continued to repair the nest and in the end of May she was observed with two other adult birds. And highly unexpectedly on 1st June we observed a bird incubating in the nest and in the middle of July volunteers of the Nature park registered hatching of a juvenile.
With laying of the eggs in the last days of May, this pair lags behind with ten days after the latest recorded laying pairs till now. We expect the juvenile to fledge in the last days of September, when almost all Egyptian vultures should already have left the country headed on migration to Africa. The two nests of the Egyptian vultures in Rusenski Lom are being observed every day by the volunteers of BSPB and the Nature park.

Considering the high rate of mortality in the years before reaching maturity only several birds from 10 juveniles survive till acquiring adult plumage. During this year the breeding success in Bulgaria numbers 23 juveniles, some of them are already flying around their nests. From totally 19 successful pairs, 15 produced one chick, while four of them raised two chicks.

We hope for all the juveniles to fledge successfully and make their way to Africa.

For more information visit: http://www.neophron.bspb.org/index-en.html


Dead Egyptian vulture found under the nest cliff. Remains from juvenile, died before leaving the nest at about 60-65 days age. Monitoring in a traditional nesting area, which was unoccupied during the last year and this year taken by newly established pair. Monitoring of vultures at a feeding site.
Dead Egyptian vulture found under the nest cliff. Remains from juvenile, died before leaving the nest at about 60-65 days age. Monitoring in a traditional nesting area, which was unoccupied during the last year and this year taken by newly established pair. Monitoring of vultures at a feeding site.