Human disturbance of an avian scavenging guild

Ecological Applications
By: , and 

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Abstract

In order to investigate the effects of human activities on relationships within foraging guilds, we examined inacanus dynamics of eagles, crows, and gulls scavenging on spawned salmon in the Pacific Northwest. We examined several hypotheses that postulate the asymmetric foraging relationships of the three guild members and that reveal the influence of competition and facilitation in these relationships. Spatial and temporal patterns of resource use by the three primary guild members varied with the presence and absence of human activity at experimental feeding stations. At control (undisturbed) stations, eagles preferred to feed >100 m from vegetative cover, whereas gulls fed <50 m from cover. At experimental (disturbed) stations, eagles rarely fed, and feeding activity by gulls increased at both near and far stations. Crows often fed on alternate food sources in fields adjacent to the river, especially when salmon carcasses were scarce, whereas eagles and gulls rarely did so. We also examined if and how the behavior of single guild members changes in the presence or absence of other guild members. In the absence of eagles, gulls and crows preferred stations far from cover, numbers of both increased at feeding stations, birds were distributed nearer to carcasses, and they fed more. We emphasize that guild theory lends important insights to our understanding of the effects of human disturbance on wildlife communities.
Publication type Article
Publication Subtype Journal Article
Title Human disturbance of an avian scavenging guild
Series title Ecological Applications
DOI 10.2307/1941814
Volume 1
Issue 1
Year Published 1991
Language English
Publisher Ecological Society of America
Publisher location Tempe, AZ
Description 11 p.
Larger Work Type Article
Larger Work Subtype Journal Article
Larger Work Title Ecological Applications
First page 215
Last page 225
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