Comparative reproductive biology of co-occurring endangered and common shrubland birds

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

Kovar, Daniel George ; Sperry ; Jinelle H

关键词: 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;   

Others  :  https://www.ideals.illinois.edu/bitstream/handle/2142/89023/KOVAR-THESIS-2015.pdf?sequence=1&isAllowed=y

美国|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

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.