Scrub-Jay Split

Scrub Jay_ColoSpgs-CO_LAH_2272In case you haven’t heard, we have a new bird on the block. Last summer the familiar Western-Scrub Jay was split into two species—the California Scrub-Jay (Aphelocoma californica) and the Woodhouse’s Scrub-Jay (Aphelocoma woodhouseii).

As you might guess, the California species lives in California. More precisely, its range runs from Baja California to as far north as Vancouver, B.C., west of the Sierras and Cascades (except where it straggles into Idaho and Nevada). You can see the map generated by birders’ sightings on ebird. Woodhouse’s Scrub-Jays are found from the Sierras east to Texas, north to Idaho, and south well into Mexico. There’s an ebird map for this species, too. I’m well acquainted with this bird—I even have them at my feeders.

I was thrilled to hear about this split. I’ve seen both birds so I suddenly added a new species to my life list—without even leaving my recliner. Yet, I wondered—why the split? I’ve always thought the birds looked a bit different, but why now, and not years ago? What convinced the ornithologists that these are in fact two species and not just regional variation in a single species?

IWestern Scrub Jay_Smartsville-CA_LAH_0537t turns out that the American Ornithological Union (AOU, the august body that makes these decisions) has been examining the species for decades. The Florida Scrub-Jay and the Island Scrub-Jay were split off in 1995, but the Western Scrub-Jay split was tabled pending more research.

In the meantime, scientists looked at both DNA and the extent of hybridization. They concluded that inter-specific mating does occur, mainly in Nevada, but it’s rare. That finding, added to the DNA studies, eventually led to last year’s decision to split the species in two. The issue is far from settled; we can likely expect further splits of Mexican subspecies in the future.

Since the two species overlap in a few places, it’s helpful to know how to tell them apart. The California Scrub-Jay is darker, its colors a bit more saturated—a more intense, deeper blue accented with whiter whites, especially on the throat and on the extended white eyebrow. The brown “mantle” on their upper back is more pronounced as well. The interior jay has a gray overtone, appropriate for a dryer climate. It’s less contrasty, and the blue collar doesn’t extend as far around the throat.

You can see the differences in these photos:

The California Scrub-Jay is on the left. (Now can you ID the birds in the other two photos? The answer is below.)

As I struggle to remember the new name, Woodhouse’s Scrub-Jay, I became curious—who is this Woodhouse, and why does he merit a bird named after him?

Samuel Washington Woodhouse (1821 – 1904) was a physician and naturalist from Philadelphia with a special interest in birds. He took part in several expeditions to the southwestern part of the U.S. His first expedition led through Oklahoma, where he was the first to compile an extensive list of the resident species. As a result, he’s known as the father of Oklahoma ornithology. In addition to the Scrub-jay, the Woodhouse’s Toad (Anaxyrus woodhousii) and Woodhouse’s Aster (Aster woodhousei) were named in his honor.
The top bird is a Woodhouses Scrub-Jay, and the lower bird is a California Scrub-Jay.


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