La Tour du Valat

Institut de recherche pour la conservation des zones humides méditerranéennes

Titre :	Selective predation of goshawk Accipiter gentilis and common buzzard Buteo buteo on the hungry hordes? (1998)
Auteurs :	Rob G. Bijlsma, Auteur
Type de document :	Article
Dans :	Limosa (71(3) 1998)
Article en page(s) :	121-123
Résumé :	During 1995-98, frequent controls of 46 nests of Goshawks (76x during egg stage, 233x during nestling stage) and 100 nests of Common Buzzards (resp. 127x and 508x) were carried out in western Drenthe (NE-Netherlands) to monitor growth and development of nestlings and to collect prey remains. All prey items were identified, weighed and measured whenever possible. Among 101 Goshawk and 844 Common Buzzard preys. 26 and 48 Starlings were found respectively, mostly juveniles and often partly plucked and eaten. Tarsus length of 21 juvenile Starlings was on average 29.2 mm (SD = 0.55, range 28.1-30.2 mm, median 29.0 mm). This was compared with tarsus lengths (at 15 days old, in which birth date = day 0) of 20 juvenile Starlings from nest boxes in the same area: on average 29.7 mm (SD = 0.68. range 28.5-31.0 mm, median 29.9 mm). Juveniles from nest boxes showed a positive correlation between body mass and tarsus length (Fig. 1). Large broods and last born young showed lowest body masses. If nestlings from nest boxes are representative of the local population, it appears that Goshawks and Common Buzzards selectively hunted for low-weight individuals (as exemplified by short tarsi), presumably fledglings with poorest condition.

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