What homebody island birds could tell us about adaptation and evolution

13Aug, 2018

By Anne Manning

In nature, organisms are constantly adapting to their surroundings. It’s why animal or plant populations with the same set of genes will do different things in different environments.

These adaptive divergences can occur within fewer generations, and at smaller spatial scales, than classic evolutionary theory would have us believe. Launching a new study, Colorado State University biologists are diving into the question of just how small these scales could be. To find out, they’re studying a rare, isolated bird that, it turns out, is a bit of a homebody.

Researchers led by Cameron Ghalambor, professor in the Department of Biology, are launching a National Science Foundation-supported study of what evolutionary biologists term “microgeographic” adaptation strategies of island scrub-jays, North America’s only island-endemic bird. Island scrub-jays live exclusively on Santa Cruz Island, one of the Channel Islands off the southern California coast.

The study is aimed at understanding how isolated species like scrub-jays somehow manage to genetically diverge, creating sub-populations that reflect specific, adaptive traits. That’s despite living in an area of less than 100 square miles, with plenty of opportunity to interbreed. What the researchers learn could provide new insight into the mechanisms by which individuals in a single population diverge across habitats, and what that could mean for conservation biology, biodiversity and evolution.

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