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Where have the Western grebes gone?

Western grebe tending a floating nest. Photo by Daniel Poleschook, Jr. and Ginger GummDo you remember seeing flocks of Western grebes in the Salish Sea numbering in the thousands?

Grebes are pretty amazing. They never go on land. In the winter they forage in marine waters and in the summer they breed on freshwater lakes in the US and Canada where they actually make floating nests (pictured above). They used to be abundant in the Salish Sea. But some estimates suggest that Western Grebes in the Salish Sea have declined by 95% over the last few decades.

So if you were out looking for grebes this past winter, you probably didn't see many.

SeaDoc has been supporting Western grebe research for many years. We've written a draft status review for their listing, which is under review with the State. They were part of Nacho Vilchis' study on marine bird declines (currently in review for publication). And we even developed an improved surgical technique for implanting transmitters in them to track their movements.

One important thing we didn't know is how wintering marine sites and summer freshwater nesting sites are connected, and whether Western grebes return to the same wintering sites or the same nesting sites year after year.

Photo by Daniel Poleschook, Jr. and Ginger Gumm of Western Grebe

Western grebe tending a floating nest. Photo by Daniel Poleschook, Jr. and Ginger Gumm

To address this question, SeaDoc helped support Diana Humple's graduate research. We just posted her Master's Thesis on the SeaDoc website. She developed genetic markers for Western Grebes and looked to see if there were differences between grebe populations.

She found there wasn't much difference between birds at 3 wintering sites (Washington, Northern California, and Southern California) or at 2 breeding colonies (Eagle Lake, California and Lake Wabauman in Alberta, Canada).

This suggests a pretty high level of gene flow between Western Grebes from different locations and means it's likely that they move between wintering sites as well as between breeding sites.

From the Salish Sea perspective, this means there's is a good possibility that "our" once large Western Grebe population has "moved" further south in an effort to find more food, as was suggested in a recent publication by Scott Wilson and others (2013)

Download Diana Humple's thesis:

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