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Conspecific brood parasitism: reevaluating a bird’s-eye view

Dailey, Helen Kay (2022) Conspecific brood parasitism: reevaluating a bird’s-eye view. Masters thesis, Northern Arizona University.

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Conspecific brood parasitism, also known as intraspecific brood parasitism, is characterized by individuals depositing eggs into the established nests of others of the same species. One of the most widely held explanations for this behavior is that the brood parasites “make the best of a bad job,” or the BOBJ hypothesis, put forward by Dawkins (1980). That is, they are able to reproduce successfully via parasitism and persist within the population despite having fitness that is less than the average of the non-parasitic, nesting individuals. We show that brood parasitism in modern birds may instead represent a conditional polymorphism that persists because nest loss, social interactions, or other environmental influences may prevent a fraction of the population from rearing offspring within their own nests. When the fitness of unsuccessful females is included in the form of a “zero class” along with the fitness of successful females, calculations of average fitness reveal that the fitness of parasitic and non-parasitic females is equivalent. These conditions are necessary and sufficient to maintain quantitative genetic variation underlying the tendency to become a brood parasite. These findings suggest that the BOBJ hypothesis as the de facto interpretation of brood parasitism should be re-examined and open the door to new understandings of the relationship between conspecific brood parasitism (CBP) and population ecology. A potential next step in this re-examination of CBP is to look to the ancestral lineage of modern birds. Like many other aspects of modern bird biology, CBP as a polymorphism in the breeding population may have a dinosaurian origin. Using a published literature review by Yom-Tov (2001) which identifies the nest characteristics of modern birds that engage in CBP, we suggest non-avian dinosaur taxa that could be viewed in the context of potential CBP.

Item Type: Thesis (Masters)
Publisher’s Statement: © Copyright is held by the author. Digital access to this material is made possible by the Cline Library, Northern Arizona University. Further transmission, reproduction or presentation of protected items is prohibited except with permission of the author.
Keywords: Bird; Brood; Conspecific; Intraspecific; Nest; Parasitism; Brood prasitism; Nessting behavior;
Subjects: Q Science > QL Zoology
NAU Depositing Author Academic Status: Student
Department/Unit: Graduate College > Theses and Dissertations
College of the Environment, Forestry, and Natural Sciences > Biological Sciences
Date Deposited: 15 Jul 2022 17:45
Last Modified: 15 Jul 2022 17:45
URI: https://openknowledge.nau.edu/id/eprint/5862

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