Thursday, October 4, 2018

The Yellow-billed Magpie, One of California's Truly Endemic Species

We have a particularly beautiful bird inhabiting our campus, but unless you live here in California, you don't get to see it except in pictures. It's one of the few true California endemic bird species, the Yellow-billed Magpie (Pica nuttalli). It is related to the Black-billed Magpie that is common across the country, but the two populations are isolated from one another by the Sierra Nevada and they've been separated since the Ice Ages. In general, the Yellow-billed Magpie is better adapted to hot temperatures like those in the Great Valley. Besides the yellow bill, the California birds have yellow around their eyes.
The Yellow-billed Magpies are gregarious, historically gathering in huge flocks and around 2008-2009 it was almost their undoing. The West Nile Virus reached the Great Valley and the magpies were particularly susceptible to infection, which was deadly much more than 90% of the time. Their populations crashed, from more than 200,000 to around 90,000. Even though I was not watching birds carefully at that time, the sudden quiet was disconcerting. It was a real tragedy. Instead of flocks of dozens or hundreds, one would see half a dozen birds at a time.

Luckily, the bird seems to be making something of a comeback. Some of the birds may have developed some immunity to the infection, and my impression is that there are more of them on our West Campus. The flock seems to be about 25 strong. I've been having problems getting close enough to them for photography, but today one landed just outside my classroom and I just happened to have my camera at that moment. I'm hopeful for their future; the world would be a dismal world without them.

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