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

Kovar, Daniel George

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https://hdl.handle.net/2142/89023 Copy

Description

Title

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

Author(s)

Kovar, Daniel George

Issue Date

2015-11-30

Director of Research (if dissertation) or Advisor (if thesis)

Sperry, Jinelle H

Department of Study

Natural Resources & Environmental Sciences

Discipline

Natural Resources & Environmental Sciences

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

M.S.

Degree Level

Thesis

Keyword(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.

Graduation Semester

2015-12

Type of Resource

text

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http://hdl.handle.net/2142/89023

Copyright and License Information

Copyright 2015 Daniel George Kovar

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