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Dyulgerova S.,Bulgarian Academy of Science | Gramatikov M.,GeoMarine Center Ltd. | Pedashenko H.,Bulgarian Academy of Science | Vassilev K.,Bulgarian Academy of Science | And 2 more authors.
Acta Zoologica Bulgarica | Year: 2015

Farmland birds are reported to decrease strongly in numbers throughout Europe over the last 30 years. Agricultural land abandonment is considered amongst the main drivers for the negative population trends. This process has been studied widely in Western Europe but the evidence for Central and Eastern Europe is limited. We examined the differences in the bird community structure among several secondary succession stages after land abandonment (since the 1940s) in central Bulgaria. Our results demonstrated that avian species richness and diversity decreased with the secondary succession, while no significant difference in the overall bird abundance was observed. The shifts in bird community pattern were mainly related to grassland specialists, which decreased in species richness, diversity and abundance along the succession gradient. Birds of European Conservation Concern were also negatively affected by the woody vegetation overgrowth. We think that in order to stop and reverse the loss of farmland bird diversity in the low-productive mountainous regions of Bulgaria, the rural sustainable development should be reinforced by implementation of agri-environmental and other policy measures that encourage effectively small-scale extensive farming. © 2015, Bulgarian Academy of Sciences. All rights reserved.


VELEVSKI M.,Macedonian Ecological Society | NIKOLOV S.C.,Bulgarian Society for Protection of Birds BirdLife Bulgaria | HALLMANN B.,40008 Rapsani | DOBREV V.,Bulgarian Society for Protection of Birds BirdLife Bulgaria | And 15 more authors.
Bird Conservation International | Year: 2014

The Egyptian Vulture has been classified as ‘Endangered’ due to a rapid population decline in India and long term declines in Europe and Africa. Although the species has been reported to be declining in Eastern Europe, no quantitative assessment of the magnitude or the causes for population declines are available. We used monitoring data from the Balkan Peninsula to estimate changes in population size and extent of occurrence of Egyptian Vultures between 1980 and 2013. We quantified population trends in three countries (Bulgaria, Greece and the former Yugoslav Republic [FYR] of Macedonia) to assess whether population declines are similar within the Balkan range states. We found a rapid and consistent decline of the Egyptian Vulture population that was largely similar among the three countries (λ = 0.940 in FYR of Macedonia, 0.951 in Bulgaria, 0.920 in Greece). As a consequence of population declines, the breeding range of Egyptian Vultures has contracted and the population in the Balkan Peninsula has fragmented into six subpopulations separated by more than 80 km. Population declines may be driven by factors such as poisoning, electrocution, direct persecution and changes in food availability which operate at large spatial scales and affect birds both on breeding grounds as well as during migration and wintering. Because the relative importance of threats to the survival of Egyptian Vultures are poorly understood, there is a critical need for research into causes of mortality and potential conservation actions that may halt and reverse population declines. Copyright © BirdLife International 2014


Oppel S.,Center for Conservation Science | Dobrev V.,Bulgarian Society for Protection of Birds BirdLife Bulgaria | Arkumarev V.,Bulgarian Society for Protection of Birds BirdLife Bulgaria | Saravia V.,Hellenic Ornithological Society | And 6 more authors.
Ibis | Year: 2015

Many populations of long-distance migrants are declining and there is increasing evidence that declines may be caused by factors operating outside the breeding season. Among the four vulture species breeding in the western Palaearctic, the species showing the steepest population decline, the Egyptian Vulture Neophron percnopterus, is a long-distance migrant wintering in Africa. However, the flyways and wintering areas of the species are only known for some populations, and without knowledge of where mortality occurs, effective conservation management is not possible. We tracked 19 juvenile Egyptian Vultures from the declining breeding population on the Balkan Peninsula between 2010 and 2014 to estimate survival and identify important migratory routes and wintering areas for this species. Mortality during the first autumn migration was high (monthly survival probability 0.75) but mortality during migration was exclusively associated with suboptimal navigation. All birds from western breeding areas and three birds from central and eastern breeding areas attempted to fly south over the Mediterranean Sea, but only one in 10 birds survived this route, probably due to stronger tailwind. All eight birds using the migratory route via Turkey and the Middle East successfully completed their first autumn migration. Of 14 individual and environmental variables examined to explain why juvenile birds did or did not successfully complete their first migration, the natal origin of the bird was the most influential. We speculate that in a declining population with fewer experienced adults, an increasing proportion of juvenile birds are forced to migrate without conspecific guidance, leading to high mortality as a consequence of following sub-optimal migratory routes. Juvenile Egyptian Vultures wintered across a vast range of the Sahel and eastern Africa, and had large movement ranges with core use areas at intermediate elevations in savannah, cropland or desert. Two birds were shot in Africa, where several significant threats exist for vultures at continental scales. Given the broad distribution of the birds and threats, effective conservation in Africa will be challenging and will require long-term investment. We recommend that in the short term, more efficient conservation could target narrow migration corridors in southern Turkey and the Middle East, and known congregation sites in African wintering areas. © 2015 British Ornithologists' Union.


Oppel S.,Center for Conservation Science | Dobrev V.,Bulgarian Society for Protection of Birds BirdLife Bulgaria | Arkumarev V.,Bulgarian Society for Protection of Birds BirdLife Bulgaria | Saravia V.,Hellenic Ornithological Society BirdLife Greece | And 7 more authors.
Biological Conservation | Year: 2016

Assessing the effectiveness of conservation measures to reverse population declines is essential to evaluate management strategies. Management solutions such as direct protection or supplementary feeding typically aim at reducing mortality or increasing productivity, but demonstrating such demographic consequences of adopted management is often difficult. Here we assess the effectiveness of large-scale management actions aimed at the conservation of an endangered vulture on the Balkan Peninsula by extending a novel analysis to estimate seasonal adult survival from observations of unmarked individuals. We monitored Egyptian Vulture Neophron percnopterus breeding success and territory occupancy over 11 years in three countries during which both nest guarding and supplementary feeding were carried out. We found little evidence that nest guarding and supplementary feeding increased breeding propensity (mean = 0.88 ± 0.32 standard deviation, n = 463), breeding success (0.82 ± 0.39), or the number of fledglings raised by successful pairs (1.3 ± 0.74). We estimated adult survival during the 23-week breeding season (mean = 0.936, 95% credible interval 0.889-0.968) and found no significant increase due to management. In the last 13 years 43 dead adult birds have been found during the breeding season, and 77% of confirmed mortalities were due to poisoning. Overall, the current management measures may have so far failed to halt ongoing population declines because the beneficial effects are insufficient to offset the loss of adult birds for example due to poisoning. We suggest that additional measures to slow the decline of Egyptian Vultures in the Balkans are required. In the short term, we urge governments to enforce anti-poison regulations that already exist. In the medium term, alternative approaches need to be developed that reduce the use of poisons and the associated accidental mortality of vultures and other wildlife species. © 2016 Elsevier Ltd.


Gerdzhikov G.,Bulgarian Society for Protection of Birds BirdLife Bulgaria | Iliev M.,Bulgarian Society for Protection of Birds BirdLife Bulgaria | Nikolov S.C.,Bulgarian Society for Protection of Birds BirdLife Bulgaria
Acta Zoologica Bulgarica | Year: 2014

A lot of studies exist on the soaring bird migration along the Eastern Mediterranean migration route. However, most of them are focused on the avian species composition and numbers, while the migration patterns and the influence of weather conditions are still poorly investigated. The present study is focused on the migration of White Storks in northeastern Bulgaria, based on data collected for 6-year period (2004- 2010) from 33 observation points. Our aim was to investigate the horizontal and vertical distribution of migrating storks, and how the dynamics of these distributions was influenced by the weather conditions. We demonstrated that the migration route of White Storks in the study area extends up to 70 km inland from the coast. The most intensive was the migration in the early afternoon, during the last 10 days of August and under north-coming winds. The majority of storks was flying above 400 m and the altitude of flight was influenced by the air temperatures and the day hour. The main driver for the flight distance from the sea was the wind direction. Considering the potential negative cumulative effects due to the high concentration of wind parks in northeastern Bulgaria, we emphasise that the prospective intentions for construction of wind farms, even located at 70 km from the coast, should be subjected to careful studies on the soaring bird migration through the area. © 2014 Institute of Biodiversity and Ecosystem Research - BAS.

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