Presentation Title

Does Island Living Shift the Mechanisms of Plumage Ornamentation in Passerines?

Format of Presentation

Poster to be presented the Friday of the conference

Abstract

Mainland birds are often much more colourful than their island counterparts. Additionally, island birds commonly have little sexual dichromatism (difference in plumage colour between sexes) when compared to mainland species. These plumage trends may be due to independent trait selection in response to environmental pressures exerted by islands, in which many colourful species underwent parallel evolution, becoming duller on islands. Alternatively, fewer dull songbirds could have successfully emigrated to islands and speciated; thus, dull birds on islands are similarly the result of evolutionary happenstance. This study aimed to determine whether island and mainland songbirds differ in plumage colour and sexual dichromatism within the context of evolutionary history. To do so, I compiled island occupation status and plumage colour scores for 5811 global passerine species. I used a Phylogenetic Generalized Least Squares analysis to control for phylogenetic influence. Male plumage scores differed between island and mainland counterparts, while female and sexual dichromatism plumage scores were not significantly different. The next step will be to examine whether island size influences plumage colouration and sexual dichromatism. This will be accomplished by analyzing the relationship between average island surface area and plumage colouration of North American island passerines.

Department

Biological Sciences

Faculty Advisor

Matthew Reudink

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Does Island Living Shift the Mechanisms of Plumage Ornamentation in Passerines?

Mainland birds are often much more colourful than their island counterparts. Additionally, island birds commonly have little sexual dichromatism (difference in plumage colour between sexes) when compared to mainland species. These plumage trends may be due to independent trait selection in response to environmental pressures exerted by islands, in which many colourful species underwent parallel evolution, becoming duller on islands. Alternatively, fewer dull songbirds could have successfully emigrated to islands and speciated; thus, dull birds on islands are similarly the result of evolutionary happenstance. This study aimed to determine whether island and mainland songbirds differ in plumage colour and sexual dichromatism within the context of evolutionary history. To do so, I compiled island occupation status and plumage colour scores for 5811 global passerine species. I used a Phylogenetic Generalized Least Squares analysis to control for phylogenetic influence. Male plumage scores differed between island and mainland counterparts, while female and sexual dichromatism plumage scores were not significantly different. The next step will be to examine whether island size influences plumage colouration and sexual dichromatism. This will be accomplished by analyzing the relationship between average island surface area and plumage colouration of North American island passerines.