Xirouchakis S.M.,University of Crete |
Fric J.,Hellenic Ornithological Society BirdLife Greece |
Kassara C.,University of Patras |
Portolou D.,Hellenic Ornithological Society BirdLife Greece |
And 7 more authors.
Ecological Research | Year: 2012
We gathered data for a four-year period (2004-2007) on the nesting ecology and reproductive performance of Eleonora's falcon in the Aegean Sea. We investigated in an indirect way the relation between clutch size and pre-laying food availability, the significance of site and pair quality on productivity, and the effects of habitat and intraspecific competition on breeding success. Overall, the species selected nest sites sheltered from sun exposure but not from the prevailing wind. Hatching, fledging, and breeding success rates were estimated at 64, 72%, and 60%, respectively. Fledglings per breeding pair ranged from 1.19 to 1.75, and fledglings per successful pair from 1.84 to 2.0, between the years. Productivity depended on parental care rather than nest-site quality. Breeding parameters varied significantly between the years, exhibiting a strong spatial yet local effect. Low success rates were recorded in specific colonies, which were attributed to adverse weather conditions and habitat degradation. Insect food availability prior to egg-laying, estimated via plant biomass, was positively correlated to clutch size. Meanwhile, low wind strengths in August, large distances from the mainland, and population size in the vicinity of the colonies had negative effects on breeding success. Considering data at the Mediterranean scale, a longitudinal trend is observed across the breeding range of this species, with breeding parameters slightly decreasing from west to east. © 2011 The Ecological Society of Japan.
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.