Reproductive Strategies in the European Blackbird, Turdus merula

Creighton, Emma (2000). Reproductive Strategies in the European Blackbird, Turdus merula. PhD thesis The Open University.

DOI: https://doi.org/10.21954/ou.ro.0000f97d

Abstract

In this thesis I explore the reproductive strategies of European blackbirds, Turdus merula in Oxford Botanic Garden using detailed observation of marked individuals and tests of genetic paternity. In Chapter Two I establish that the population's breeding ecology is comparable to other studies on the species and identify the importance of nesting cover in both territorial distribution and nesting success. In Chapters Three, Four and Five I demonstrate that both males and females pursue mixed reproductive strategies and engage in extra-pair copulations. Female tactics are covert and, backed up by a review of the literature, I suggest that they are constrained by the costs of attracting sexual harassment from males. I find that males employ counter-strategies of mate guarding and territorial defense and that their tactics vary according to social circumstances. In contrast, I find that females do not use counter-strategies of either close association or repeated copulation, and review of the literature suggests a reconsideration of female mate guarding theory. In Chapter Six I link earlier research into European blackbird breeding ecology with observations from this study to show the influence that availability of dense vegetation for nesting cover has on mate acquisition and subsequent sexual strategies during the breeding season. In addition to the contributions to sexual selection theory described above, this thesis contributes to knowledge of the breeding biology of the European blackbird by adding explanations of the mate acquisition and sexual strategies that give rise to this biology.