Western Scrub-Jay Species Split by AOU

Birders have been known to keep all sorts of birding lists—species ever seen; those seen this year; seen in this state, this county, this park, this yard—even lists such as “birds I’ve ID’d on television,” “birds I’ve seen on a wire,” or “birds I’ve found dead in my yard.”  (Some birders are darker than others.)  I primarily keep just a list of birds I’ve seen or heard anywhere, any time (referred to as a “life list”). As this total grows, it gets harder to add a new species. But one recent day in July, that total increased by one and I didn’t even get off the couch. Score!

That day, the American Ornithologists’ Union—the organization regarded by both scientists and recreational birders as the authority on North American bird taxonomy—announced a split of the western scrub-jay species into two species:  California scrub-jay and Woodhouse’s scrub-jay.

How can you tell these new species apart?  Geographic distribution provides one of the easiest clues. California scrub-jays principally inhabit coastal regions from Washington to Baja California and reach up the western slope of the Sierra Nevada. Woodhouse’s scrub-jays range from the Great Basin and the Rocky Mountains to the Chihuahuan Desert. (The two species do overlap in a small part of western Nevada, so look carefully there!)

Differences in appearance between these two species are a bit subtle. California scrub-jays sport a more vibrant, deep blue plumage with a blue stripe—a “collar,” of sorts—stretching onto their chests. Woodhouse’s scrub-jays are a paler blue overall and usually lack the distinctive blue collar. California scrub-jays’ preferred oak woodlands habitat provides a consistent supply of acorns. These birds have evolved heavier, hooked beaks that can demolish those tough shells. Woodhouse’s scrub-jays live where pinyon pines and junipers offer the most reliable source of food. Woodhouse’s have narrower beaks, presumably due to the birds’ need to extract smaller, more delicate pinyon nuts from their cones.

The California scrub-jay kept the western scrub-jay’s original scientific name of Aphelocoma californica while Woodhouse’s scrub-jay became Aphelocoma woodhouseii. The shared genus name refers to the lack of a crest, such as that found on a steller’s or blue jay:  Aphelocoma means “smooth hair,” from the Greek apheles (“smooth”) and kome (“hair of the head”). The California’s species name (californica)denotes that the bird was first documented in—wait for it!—California. Both the species and common names of Woodhouse’s scrub-jay honor Samuel Washington Woodhouse, a 19th-century physician and naturalist who accompanied Captain Lorenzo Sitgreaves on an expedition from San Antonio to San Diego. “Scrub-jay” arises from both species’ scrub habitats—coastal and oak scrub for California scrub-jay and pinyon-juniper scrub for Woodhouse’s scrub-jay.

The Woodhouse’s scrub-jay has long been considered quite distinct from its more coastal cousins, and scientists have unofficially used that name for this group as early as the 1940s. July’sofficial change is neither the first nor likely the final word on the scrub-jay genus, if there ever is a final word in avian taxonomy. In 1998, the island scrub-jay (found only on California’s Santa Cruz Island) and the Florida scrub-jay were split off as distinct species. And some scientists believe another deserving split involves two subspecies still in the woodhouseii species. Stay tuned.

Have you seen a scrub-jay in California?  (You’d practically have to wander around the coastal slope of North County with your eyes shut and your ears plugged to miss them.)  Tick off California scrub-jay on whatever list you might keep. How about a scrub-jay in, say, Colorado or New Mexico?  Woodhouse’s scrub-jay—check!  And if you answered “yes” to both of these questions, your total also just increased by one without your ever leaving the house. Congratulations!

And some people say birding is hard work…

Photo credit -Steve Brad (2011)

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