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Thesis Abstract – Cowen (2016)


Offspring dispersal and territory acquisition of Western scrub-jays (Aphelocoma californica californica) at the Bernard Field Station

Author and college:

Madeline Cowen, Pomona College


Spring 2016


Bachelor of Arts in Biology


Rachel Levin, Department of Biology, Pomona College


The Corvid genus Aphelocoma is ecologically diverse, consisting of species ranging from Mexico to Florida to Oregon. Although cooperative breeding is thought to be basal in the genus, Aphelocoma contains some species that are cooperative breeders and some that are not. The Western scrub-jay, Aphelocoma californica, is a non-cooperatively breeding species that, although widely distributed, is not widely studied. As dispersal patterns vary between cooperatively and non-cooperatively breeding species, understanding the movement and territory patterns of this species could better inform our understanding of the evolution of breeding systems in this genus, especially as it relates to habitat availability. I observed the territory distribution of Western scrub-jays on an isolated parcel of Southern California native coastal sage scrub and performed microsatellite analysis on DNA samples collected from them.

Understanding genetic kinship confirmed sex-biased dispersal patterns and the presence of a floater region in the study site, thus supporting a model that Western scrub-jay females typically disperse and males remain close to their natal territory. This method of combining microsatellite data with field observation should be used to address future questions on dispersal patterns and territory acquisition by including kinship as a necessary part of the analysis.

For more information:

Contact Wallace Meyer – Wallace.Meyer@Pomona.edu

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