La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Wind speed as a determinant of kleptoparasitism by Eurasian Kestrel Falco tinnunculus on Short-eared Owl Asio flammeus
Auteurs :	H. Fritz, Auteur
Type de document :	Article
Dans :	Journal of Avian Biology (29(3) SEP 1998)
Article en page(s) :	331-333
Langues:	Anglais
Résumé :	Twenty-five kleptoparasitic attempts by Kestrels on Short-eared Owls were recorded in 16 afternoons of observation (70 hours) during the winter of 1996-97 in western France. Nine attempts were successful. The daily hunting yield of Kestrels is related to the time spent flight-hunting, an energetically costly hunting technique. Medium to strong winds allow Kestrels to use flight-hunting at a lower cost, hence increasing the rate of net energy intake. I found that kleptoparasitism occurred more frequently when wind speed was unfavourable for flight-hunting (i.e. weak winds). Food theft was more successful when done by a pair; the female always initiated the attacks. One stolen prey per day was estimated to compensate for 50% of the potential reduction in hunting yield caused by the lesser time spent flight-hunting in poor wind conditions.

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