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Title:Comparative reproductive biology of co-occurring endangered and common shrubland birds
Author(s):Kovar, Daniel George
Advisor(s):Sperry, Jinelle H
Department / Program:Natural Resources & Environmental Sciences
Discipline:Natural Resources & Environmental Sciences
Degree Granting Institution:University of Illinois at Urbana-Champaign
Subject(s):comparative ecology
habitat selection
interspecific competition
endangered species management and conservation
avian ecology
nest site selection
nest survival
brood parasitism
black-capped vireo
Vireo atricapilla
white-eyed vireo
Vireo griseus
Abstract:Black-capped vireos (Vireo atricapilla) and white-eyed vireos (Vireo griseus) are closely related and ecologically similar. Despite these similarities, white-eyed vireos are widely distributed and common, whereas the black-capped vireo has a restricted breeding range and is federally endangered. Here I address this apparent paradox with a comparative ecological study of co-occurring black-capped and white-eyed vireos. I studied vireos in shrublands and woodlands in central Texas, USA in 2013 and 2014. I used point count surveys (n = 256) and nest monitoring (n = 145) to determine arrival dates, settlement patterns, nest site selection, and, ultimately, nest survival relative to temporal and habitat factors. Additionally, I conducted reciprocal playback trials (n = 16) to test for the presence of interspecific aggression. White-eyed vireos arrived first and established territories in shrub and woodland habitat with equal probability. Black-capped vireos arrive after white-eyed vireos and settled in greater numbers in shrubland habitat. White-eyed vireos begin initiating nests earlier than black-capped vireos and selected nest sites surrounded by taller, more mature, and more densely wooded vegetation. Playback trials failed to detect evidence of interspecific aggression, suggesting that competition with white-eyed vireos is not currently limiting black-capped vireos. For both species, nest survival declined as the season progressed, and was greater for nests in taller, more mature habitat. Accordingly, overall nest survival appeared greater for white-eyed vireos than black-capped vireos suggesting that the flexibility demonstrated by white-eyed vireos in where and when they nest confers a reproductive advantage.
Issue Date:2015-11-30
Rights Information:Copyright 2015 Daniel George Kovar
Date Available in IDEALS:2016-03-02
Date Deposited:2015-12

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