TY - JOUR
T1 - Simultaneous decline in Steppe Eagle (Aquila nipalensis) populations and Levant Sparrowhawk (Accipiter brevipes) reproductive success
T2 - Coincidence or a Chernobyl legacy?
AU - Yosef, Reuven
AU - Fornasari, Lorenzo
N1 - Funding Information:
Acknowledgements — We thank B MeybguKB,rd islPHtBeo lionm, and DA Ellis for improving earlier versions of the manuscript. We thank the hundreds of voluns wtehheahorve celpo tenehdd uct visual migration su.W rSCv ealayAnHridnka d irnees tinrumental the raptor-banding prograEata mDirtls.N mCheesrho nevelpt ed find Russian manuscripts and M Markovets translated from the Russian.
PY - 2004/1/1
Y1 - 2004/1/1
N2 - Visual migration surveys, especially at bottlenecks, can be a vital tool to evaluate population fluctuations in environmentally sensitive species. Raptors are considered to be important bioindicators that can help identify environmental catastrophes. Substantial proportions of the global population of Steppe Eagles (Aquila nipalensis) and Levant Sparrowhawk (Accipiter brevipes) concentrate at Eilat, Israel, during the spring and autumn migrations, but counts from seven autumn and seven spring migration surveys indicate a constant decline in Steppe Eagle numbers. Further, the number of juveniles observed in these counts dropped steadily from 30% in the early 1980s, to 1.4% in 2000. The numbers observed at Eilat are well below the range of the numerical fluctuations observed in previous surveys. In Levant Sparrowhawks, no decline in total numbers is evident, but a significant change in the adult to juvenile age ratio was noted between the population trapped in the 1980s and that sampled in the late 1990s. The cumulative evidence of the decrease in the total numbers of Steppe Eagles, the decreasing proportion of subadults within the population, and the decrease in adult:young ratio in the Levant Sparrowhawk population trapped leads us to suggest that the Chernobyl accident on 26 April 1986 may have negatively affected wildlife populations, not only to the west with the spread of the radio-active plume, but farther east than previously assumed.
AB - Visual migration surveys, especially at bottlenecks, can be a vital tool to evaluate population fluctuations in environmentally sensitive species. Raptors are considered to be important bioindicators that can help identify environmental catastrophes. Substantial proportions of the global population of Steppe Eagles (Aquila nipalensis) and Levant Sparrowhawk (Accipiter brevipes) concentrate at Eilat, Israel, during the spring and autumn migrations, but counts from seven autumn and seven spring migration surveys indicate a constant decline in Steppe Eagle numbers. Further, the number of juveniles observed in these counts dropped steadily from 30% in the early 1980s, to 1.4% in 2000. The numbers observed at Eilat are well below the range of the numerical fluctuations observed in previous surveys. In Levant Sparrowhawks, no decline in total numbers is evident, but a significant change in the adult to juvenile age ratio was noted between the population trapped in the 1980s and that sampled in the late 1990s. The cumulative evidence of the decrease in the total numbers of Steppe Eagles, the decreasing proportion of subadults within the population, and the decrease in adult:young ratio in the Levant Sparrowhawk population trapped leads us to suggest that the Chernobyl accident on 26 April 1986 may have negatively affected wildlife populations, not only to the west with the spread of the radio-active plume, but farther east than previously assumed.
UR - http://www.scopus.com/inward/record.url?scp=2442431719&partnerID=8YFLogxK
U2 - 10.2989/00306520409485407
DO - 10.2989/00306520409485407
M3 - Article
AN - SCOPUS:2442431719
SN - 0030-6525
VL - 75
SP - 20
EP - 24
JO - Ostrich
JF - Ostrich
IS - 1-2
ER -