Covariation between plumage colour polymorphism and diet in the Barn Owl Tyto alba

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serval:BIB_64FF3344F751
Type
Article: article from journal or magazin.
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Institution
Title
Covariation between plumage colour polymorphism and diet in the Barn Owl Tyto alba
Journal
Ibis
Author(s)
Roulin A.
ISSN
0019-1019
Publication state
Published
Issued date
2004
Peer-reviewed
Oui
Volume
146
Number
3
Pages
509-517
Language
english
Abstract
Several hypotheses might explain the evolution and maintenance of colour morphs within animal populations. The 'alternative foraging strategy' hypothesis states that alternative colour morphs exploit different ecological niches. This hypothesis predicts that morphs differ in diet, either because foraging success on alternative prey species is morph-dependent or because differently coloured individuals exploit alternative habitats. I examined this prediction in the Barn Owl Tyto alba, a bird that varies in plumage coloration continuously from dark reddish-brown to white. On the European continent, Owls are light-coloured (subspecies T. a. alba) in the south and reddish-brown (T. a. guttata) in the north; in central Europe the two subspecies interbreed, generating many colour variants. If plumage coloration indicates alternative foraging strategies, in sympatry dark- and light-coloured owls should consume prey species that are typical of the diets of T. a. guttata and T. a. alba in allopatry, respectively. In line with this prediction, both in allopatry and in sympatry in Switzerland T. a. guttata fed primarily upon Common Voles Microtus arvalis and T. a. alba upon Wood Mice Apodemus spp. Statistical analyses suggest that morph-dependent diet did not arise from a non-random habitat distribution of owls with respect to plumage coloration. This suggests that foraging success upon alternative prey is morph-dependent.
Keywords
APOSTATIC SELECTION, PREDATION, FEMALE, DIMORPHISM, BEHAVIOR, RODENTS, ARANEAE, MORPHS, PREY
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Create date
24/01/2008 18:42
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20/08/2019 15:21
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