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Home ยป Antipredation Role of Clumped Nesting by Marsh-Nesting Red-Winged Blackbirds
Antipredation Role of Clumped Nesting by Marsh-Nesting Red-Winged Blackbirds
Publication Type: | Journal Article |
Year of Publication: | 1988 |
Authors: | Picman, J, Leonard, M, Horn, A |
Journal: | Behavioral Ecology and Sociobiology |
Volume: | 22 |
Issue: | 1 |
Date Published: | 1988 |
ISBN Number: | 03405443 |
Keywords: | Agelaius, Agelaius phoeniceus, Cistothorus, Cistothorus palustris, Icteridae, Troglodytes, Troglodytes troglodytes, Troglodytidae, Turdidae, Turdus, Turdus iliacus, Turdus maximus, Turdus merula |
Abstract: | Red-winged blackbirds, Agelaius phoeniceus, breed in marshes in high densities and their nests are frequently clumped. Because predation is consistently the most important cause of redwing nesting mortality, high densities of breeding individuals could be an anti-predation adaptation. In our study site predation by marsh wrens, Cistothorus palustris, was the main cause of redwing nesting losses. In situations when marsh wrens were near, predation rates on redwing nests decreased with increasing female density. Group life could reduce predation because of improved nest defense, selfish herd effects, or predator dilution effects. We differentiated between these possibilities by introducing experimental colonies consisting of 3, 6, and 9 artificial nests near and away from active redwing nests. The experimental colonies near active nests suffered less predation, but predation rates were not correlated with colony size or a nest's location within the colony. Therefore, the advantage of group life in this population is probably mutual nest protection. |
URL: | http://www.jstor.org/stable/4600113 |
Short Title: | Behavioral Ecology and Sociobiology |
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