Naturalist’s Notebook: Two Forms of the Western Scrub-Jay
By John Schmitt
October 15, 2009
Update, August 2016: The two jay “forms” described in this article were formally split into separate species by the American Ornithologists’ Union. They are now known as the California Scrub-Jay and the Woodhouse’s Scrub-Jay.
November 2008 to January 2009, Tillie Creek Campground, Kern River Valley, Kern County, California
For the second time in eight years I found an “Interior” or “Woodhouse’s” form of the Western Scrub-Jay at Tillie Creek Campground, allowing me rare opportunities over the next several weeks to compare this washed-out grayish form with the more lustrous and somewhat bulkier “Coastal” Western Scrub-Jay.
The Woodhouse’s scrub-jay wasn’t always easy to locate, and many times I failed to find it during my visits. But when I did locate it, the bird was usually in the company of the abundant resident jays to which it was submissive, quickly giving way to their aggressive attentions. Many an observation was spoiled when a bullying local jay would chase the Woodhouse’s scrub-jay away through the woods. Still, I managed to observe this wayward jay repeatedly for almost two months, and I was able to compare the plumage, behavior, and vocalizations of the two types.
My first encounter with this subspecies at this location had occurred a few weeks after I saw a remarkable flock of migrating Western Scrub-Jays on 1 October 2000. On that late autumn morning, I observed Western Scrub-Jays—numbering between 70 and 90 birds—crossing high over the Kelso Valley’s desert scrub in a long open file and, to my astonishment, I even spotted two Steller’s Jays among them. When the jays reached the hillsides rising steeply from the valley’s southern edge, they immediately started moving up toward the ridgeline by hopping and making short flights over the boulders and scrub until, one by one, they disappeared over the high ridge.