Costs and benefits of host use by brood parasitic birds

Interactions between hosts and their brood parasites have dramatic effects on reproductive outcomes and survival for all participants. Using an integrative approach, my dissertation focuses on the effects of these interactions through both large-scale comparative patterns of host use across brood parasites and nest-scale social dynamics between the obligate parasitic brown-headed cowbirds (Molothrus ater) and a cavity-nesting host species, the prothonotary warbler (Protonotaria citrea). First, I use comparative methods to evaluate ecological, climatic, and behavioral factors predicted host use across 81 different species of brood parasites. My findings are consistent with the theoretical expectation that ecological risks and environmental unpredictability should favour the evolution of bet-hedging in the evolution of brood parasitic host use. Second, I utilize existing data on experimental parasitism of prothonotary warbler nest boxes that measured circulating corticosterone, immune response, and return rates in adult warblers raising broods with or without cowbirds. This study reveals that male, but not female cowbirds, show increased baseline corticosterone when rearing a brood parasite and in turn lower return rates in following breeding seasons. Brood parasitism also decreased both the body condition and immune response of both sexes of host parents. Finally, I use field experiments in prothonotary warbler nest boxes to determine the effects of internal nest dynamics between parasitic nestlings, host nestlings, and host parents. These experiments support the hypothesis that the social nest environment has profound effects on cowbird nestling survival and their interaction with competition from host nestlings.

Name thesis:degree_name

Ph.D.

Level thesis:degree_level

Dissertation

Discipline thesis:degree_discipline

Biology

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2022

Author dc:creator

• Antonson, Nicholas Dolan

Contributors dc:contributor

• Hauber, Mark E
• Schelsky, Wendy M
• Bell, Alison
• Dugas, Matthew
• London, Sarah

• Brood Parasitism
• Cowbird
• Protonotaria
• Citrea
• Niche Construction
• Bet-hedging
• Brood Reduction

Statement dc:rights

• Copyright 2022 Nicholas D. Antonson

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/117776

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F117776