Global ETD Search
Search theses and dissertations gathered from participating repositories worldwide. Every result links back to the library that holds it. No account is needed.
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Showing 1 to 20 of 29 for “"cowbird"”.
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Is timing everything? Examining the importance of the timing of parasitism to cowbird reproductive success
Submission original under an indefinite embargo labeled 'Open Access'. The submission was exported from vireo on 2025-10-19 without embargo terms
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Assessing the Imprint of Geography, Host Species, Land Cover and Space on the Local Abundance of a Generalist Nest Parasite, the Brown-headed Cowbird
The Brown-headed Cowbird is an obligate nest parasite suspected of causing local population declines in several threatened and endangered passerine species. Much attention has been directed towards uncovering the fundamental factors that affect cowbird abundance; however, no study has evaluated …
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Reproductive success of a generalist brood parasite predicts the rate of parasitism in the subsequent year
Brown-headed cowbirds (Molothrus ater) rely solely on hosts to raise their young. Although cowbirds parasitize 200+ species, recent evidence suggests that females avoid unsuitable hosts that either reject parasitic eggs or provide incompatible parental care. Female cowbirds may be able to improve …
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Mechanisms underlying population dynamics of a migratory songbird in a fragmented forest
… considered edge effects (nest predation and cowbird brood parasitism), whereas others are attributed to fragment size and isolation (low pairing success, area sensitivity, unstable population sizes). I studied the impact of Brown-headed Cowbird (Molothrus ater) brood parasitism and of nest …
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Population Dynamics of the Endangered Black-capped Vireo (Vireo atricapilla)
… high rates of parasitism by the brown-headed cowbird (Molothrus ater) across its breeding range from northeastern Mexico to southern Oklahoma. The largest population located on the Fort Hood Military Reservation in central Texas is well-studied, but its role in landscape-level vireo population …
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Natal dispersal and first-year survival in a neotropical migratory songbird
… the effects of season, presence of a cowbird nestmate, brood size, and nestling body condition on the first-year survival probabilities. To date, this is the first study to document that both fledging date and the presence of a cowbird nestmate affect first-year survival in a migratory …
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Nest Predation by brown-headed cowbirds (Molothrus ater)
… this ‘farming’ hypothesis for the brown-headed cowbird (Molothrus ater). I found evidence that cowbird attacks are not uncommon, a basic requirement of the hypothesis. Furthermore, I found multiple lines of evidence that cowbird attacks are not indiscriminate, but directed at non-parasitized …
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The Effects of Global Change on Avian Biodiversity
… at risk of nest parasitism from Brown-headed Cowbirds, an obligate brood parasite. Because cowbird parasitism can reduce the reproductive success of the host species, some rare and endangered species have been managed with cowbird removals. I found that there are fewer cowbirds than expected …
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Nesting ecology and conservation of shrubland birds in a fragmented urbanized landscape in northeastern Illinois
… species, and abandonment due to Brown-headed Cowbird (Molothrus ater) parasitism were also documented. All nests experiencing Brown-headed Cowbird parasitism failed (n=5). Red-winged Blackbird (Agelaius phoeniceus) was one of the most successful species; Willow Flycatcher (Empidonax traillii) …
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The nest defense and nest-destroying behaviors of house wrens
… the house wren model compared to the bluebird or cowbird model in the egg stage but showed no differences among model species in the nestling stage. Females exhibited no defense differences among model species. Male defense levels were affected by their breeding strategy, as attentive males were …
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An Experimental Study of Behavioral Responses to Nest Predation and Brood Parasitism in a Migratory Songbird
… where brood parasitism by Brown-headed Cowbirds (Molothrus ater) and nest predation can greatly reduce reproductive success. I studied populations of Prothonotary Warblers (Protonotaria citrea) in a fragmented bottomland forest during 1993--2000 and conducted field experiments to …
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Behavioral ecology of juvenile brown-headed cowbirds: implications for the evolution and maintenance of avian brood parasitism
… I conducted research on juvenile brown-headed cowbirds (Molothrus ater) to elucidate the factors that contribute to the evolution and persistence of avian brood parasitism. To avoid adopting the behaviors and mate choice preferences (sexual imprinting) of the foster species, juvenile cowbirds …
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Age-specific mortality, pre- to post-fledging carryover effects, and the timing of fledging in altricial songbirds
… if carryover effects occur in brood parasitic cowbirds. I found evidence for pre- to post-fledging carryover effects of wing development in all species I examined, with individuals with less developed wings exhibiting poorer flight ability and experiencing higher rates of mortality after …
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Testing proximate causes and ultimate explanations of social cue use for habitat selection by songbirds
… Results from an experiment with Brown-headed Cowbird models (Molothrus ater; a brood parasite that reduces reproductive success) revealed that Yellow Warblers behaved more aggressively towards cowbirds when apparent conspecific density was high. Results from these studies provide insight as to …
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Effects of Grazing on Nongame Breeding brids, Insects, and Vegetation in Conservation Reserve Program Grasslands in North Dakota
… Sparrow, Red-winged Blackbird, and Brown-headed Cowbird composed a majority of the species composition in 1992 and 1993. Mean density of male birds (all species combined) exhibited a downward trend from 1992 to 1993 which was most likely due to colder temperatures and greater precipitation in …
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Survey of Nasal Mites (Acari: Rhinonyssidae, Ereynetidae, Turbinoptidae) in Birds from Three States in the United States
… collected from the brood parasite, brown-headed cowbird (Molothrus ater), in specimens from Texas and Arkansas. For this survey, 126 individuals were analyzed, and 84 (66.6 %) were found to be infested with nasal mites, which included new host records for the cowbirds. I addressed the question of …
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Landscape Fragmentation and Grassland Patch Size Effects on Non-game Grassland Birds in Xeric Mixed-grass Prairies of Western South Dakota
… sparrows, western meadowlarks, brown-headed cowbirds, chestnut-collared longspurs, bobolinks and red-winged blackbirds. Grasshopper sparrows and western meadowlarks were observed in >99% of grassland patches. Avian community composition was affected by landscape fragmentation and grassland …
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Using Occupancy Models to Predict Grassland Bird Distributions in Southeastern Alberta
… Sparrow (Ammodramus bairdii), Brown-headed Cowbird (Molothrus ater), Chestnut-collared Longspur (Calcarius ornatus), Clay-colored Sparrow (Spizella pallida), Horned Lark (Eremophila alpestris), Long-billed Curlew (Numenius americanus), Marbled Godwit (Limosa fedoa), McCown's Longspur …
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Wildlife Use of Wastewater Ponds at the Idaho National Engineering Laboratory
… blackbird, Brewer's blackbird, and brown-headed cowbird. Most of the common species nested at or near the ponds. Species richness was greatest in May and September. Waterfowl had highest use in April, May, August, and September. Shorebirds were most common in May and July. The greatest number of …
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