What to look for to recognize not only Florida Scrub-Jay and Island Scrub-Jay but also two forms of Western Scrub-Jay -- "California" and "Woodhouse's."
Published: February 20, 2009
If a nonbirding friend from California tells you he has blue jays in his yard, he's demonstrating one reason why ornithologists capitalize the English names of bird species. Those backyard birds on the west coast are blue jays, but they're not Blue Jays, since that official name is reserved for the familiar, crested eastern bird.
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So what should we call those jays? It seems your friend isn't the only one who's confused. Currently, we call that species the Western Scrub-Jay, but its name has changed recently and will probably change again.
Up until the 1990s, we had a widespread bird in North America called the Scrub Jay, with several very distinct-looking populations. In 1995, a committee of the American Ornithologists' Union (AOU) formally split the bird into three species: the Florida Scrub-Jay, Western Scrub-Jay, and Island Scrub-Jay.
Alert birders were not surprised by the move, because many observers had long noticed the differences among the forms. In addition, we were aware that the Western Scrub-Jay included two distinct types. One was found throughout California and Baja, extending north to extreme southern Washington. The other lived in the interior, from Nevada and the eastern edge of California east to Texas.
A study published just last October looked at the DNA of Western Scrub-Jays and found very strong divergence between the two forms. The authors suggested that the species be split in two, with the coastal form becoming "California Scrub-Jay" and the interior bird being called "Woodhouse's Scrub-Jay."
If the AOU formalizes the split, all birders will pay attention to the distinctions between the forms. In most places, range will identify the birds. The coastal (California) and interior (Woodhouse's) scrub-jays overlap only in Douglas County in western Nevada, where they interbreed to a limited extent. But there are many differences besides range.
"California Scrub-Jay" is much more colorful and contrasting than its inland relative. It seems more common over most of its range, favoring oak woodland and often living in parks and yards. "Woodhouse's Scrub-Jay" has a more muted pattern, and its behavior seems muted, too: Often uncommon and sparsely distributed, it seems shier and more elusive than the coastal bird. Often it lives in pinyon-juniper habitat. The dull colors and muted contrast of this form make it more similar to Mexican Jay, which is common in oak woodland from southern Arizona to western Texas.
Even within the "California" and "Woodhouse's" scrub-jays, there is regional variation. Within the state of California, the birds average a little paler toward the east and smaller toward the south. In the interior, the birds in central Texas are somewhat brighter and more colorful than those in the western part of the range. These local flavors remind us that traveling birders should look for variation in all birds, even those that may be common backyard species for some.
What to look for
Blue collar. How distinct and contrasting is it? Does it set off a very white throat patch, or is the throat more blended and gray?
Back patch. Is it brown, gray, or pale gray, and how much does it contrast with the surrounding blue?
Head features. Bill shape, forehead color, and contrast of ear patch are all significant.
Range. Scrub-jays are mostly sedentary, so looking at the map will usually tell you the bird's identity.
The biggest difference between Florida Scrub-Jay and other scrub-jays is its cooperative breeding system. Territories are held by family groups, and young birds stay on the territory, sometimes for years, helping to raise subsequent generations. Among other scrub-jays in the U.S. and northern Mexico, territories are held by pairs, not family groups. However, the Mexican Jay is also a social breeder, especially in its Arizona populations. And the southernmost form of scrub-jay in Mexico - which may deserve status as a separate species, Sumichrast's Scrub-Jay - may also hold group territories and practice cooperative breeding.
Scrub-jays and relatives in North America
• Western Scrub-Jay (including "California Scrub-Jay" and "Woodhouse's Scrub-Jay")
• Island Scrub-Jay
• Florida Scrub-Jay
• Mexican Jay
The California form of Western Scrub-Jay was the subject of an ingenious observation by field biologist Joseph Grinnell in the 1930s. Noting that acorns always rolled downhill, Grinnell wondered how there could be any oaks growing on hilltops. Then he noticed that scrub-jays, industriously gathering acorns to hide them away in the ground, often flew uphill. Observations elsewhere have since confirmed the importance of various jays (including Blue Jays in the east) as acorn dispersers.