Scale-Dependent Habitat Selection of Nesting Great Egrets and Snowy Egrets

Stolen, Eric D. and Collazo, Jaime A. and Percival, H. Franklin (2007) Scale-Dependent Habitat Selection of Nesting Great Egrets and Snowy Egrets. Waterbirds, 30(3), pp. 384-393.

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Foraging habitat selection of nesting Great Egrets ( Ardea alba ) and Snowy Egrets ( Egretta thula ) was investigated within an estuary with extensive impounded salt marsh habitat. Using a geographic information system, available habitat was partitioned into concentric bands at five, ten, and 15 km radius from nesting colonies to assess the relative effects of habitat composition and distance on habitat selection. Snowy Egrets were more likely than Great Egrets to depart colonies and travel to foraging sites in groups, but both species usually arrived at sites that were occupied by other wading birds. Mean flight distances were 6.2 km (SE = 0.4, N = 28, range 1.8-10.7 km) for Great Egrets and 4.7 km (SE = 0.48, N = 31, range 0.7-12.5 km) for Snowy Egrets. At the broadest spatial scale both species used impounded (mostly salt marsh) and estuarine edge habitat more than expected based on availability while avoiding unimpounded (mostly fresh water wetland) habitat. At more local scales habitat use matched availability. Interpretation of habitat preference differed with the types of habitat that were included and the maximum distance that habitat was considered available. These results illustrate that caution is needed when interpreting the results of habitat preference studies when individuals are constrained in their choice of habitats, such as for central place foragers.

Item Type: Article
Title: Scale-Dependent Habitat Selection of Nesting Great Egrets and Snowy Egrets
Personal Creator/Author:
Stolen, Eric D.
Collazo, Jaime A.
Percival, H. Franklin
Journal or Publication Title: Waterbirds
Volume: 30
Number: 3
Page Range: pp. 384-393
Date: 2007
ISSN: 1524-4695
Issuing Agency: Florida Cooperative Fish and Wildlife Research Unit
Additional Information: This document was submitted by the Florida Cooperative Fish and Wildlife Research Unit
Uncontrolled Keywords: foraging habitat, habitat selection, flight distance, scale, Great Egret, Ardea alba, Snowy Egret, Egretta thula, impounded habitat, coastal wetlands
Subjects: Biology
Item ID: 5592
Depositing User: Stephanie Haas
Date Deposited: 01 Jun 2011 14:07
Last Modified: 29 Sep 2011 14:46

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