CR 42:217-222 (2010)  -  DOI: https://doi.org/10.3354/cr00900

Rapid advances in the timing of the spring passage migration through Israel of the steppe eagle Aquila nipalensis

Piotr Zduniak1, Reuven Yosef2, Tim H. Sparks3, Henk Smit2, Piotr Tryjanowski3,*

1Department of Avian Biology & Ecology, Faculty of Biology, Adam Mickiewicz University, Umultowska 89, 61-614 Poznań, Poland
2International Birding and Research Centre in Eilat, PO Box 774, Eilat 88000, Israel
3Institute of Zoology, Pozna´n University of Life Sciences, Wojska Polskiego 71 C, 60-625 Pozna´n, Poland
*Corresponding author. Email:

ABSTRACT: We examined phenological change in the spring migratory passage of the predatory steppe eagle Aquila nipalensis from 1977 to 2008. Data were collected at Eilat, Israel, a globally important site for migrating raptors. Changes in the observation dates of spring passage migration were examined using correlation and regression analyses to assess changes over time as well as potential relationships with temperature and with the Indian Ocean Dipole, an index of climate in the wintering area. Over the study period, the number of recorded steppe eagles decreased significantly, as did the proportion of juveniles. Despite the population decrease there was a rapid advance in first spring passage date. Although changes in passage dates were related to environmental conditions in wintering and en-route areas, we suggest that one possible additional reason for such a rapid advance is due to increasing competition between individuals for breeding territories due to dwindling habitats. In addition, changes to some aspects of the passage distribution may be a consequence of a changing age structure.


KEY WORDS: Israel · Trends · Passage migration · Population size · Predation · Indian Ocean Dipole · Temperature


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Cite this article as: Zduniak P, Yosef R, Sparks TH, Smit H, Tryjanowski P (2010) Rapid advances in the timing of the spring passage migration through Israel of the steppe eagle Aquila nipalensis. Clim Res 42:217-222. https://doi.org/10.3354/cr00900

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