Westerns Rule

Western Grebes (Aechmophorous occidentalis)

When I see the big grebes on the North Basin, they’re almost always of the Clark’s variety, with the dark crown clear of the eye and the beak bright yellow. See, e.g., “Grebe Gathering,” Mar 13 2022. This week the tables turned and Western Grebes took over. Something like fifty of them hung out in a loose flock, all wide awake in the early morning, a few of them feeding. There was no doubt about the ID. The dark crown completely covered the eye and the beak was a muddy dark with a streak of dull yellow. Here’s a few snapshots of individual members of the flock:

A few Clark’s Grebes were also on the water, performing what looked like shepherd duty among the scaup that assembled in readiness for northward migration. They didn’t interact with the Clark’s. The Western and the Clark’s are so closely related that for a century scientists thought they were just color variations of the same species. Then close observation showed that Western and Clark’s rarely formed pairs and even more rarely produced hybrids. Although the birds’ physiology and behavior are practically identical, and mixed flocks are common, they can tell one another apart in their mating choices.

Westerns do their breeding in freshwater lakes throughout California (among other places); for example, Klamath and Tule lakes, Goose and Clear lakes, Eagle Lake, Lake Almanor, Topaz Lake, and others. They come to the coast in winter because the feeding is better then on shallow salt water. Their main food is fish.

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