Western Scrub-Jay

On the wild side—October, 2013

by Tina Mitchell

I don’t know about where you live, but we have been in the midst of a major “jay invasion” these past few weeks.  One morning, we counted at least 15 Western Scrub-Jays (and a bonus of maybe a dozen Steller’s Jays).  Usually, by this time of year, the scrub-jay family groups have started to spread out and we only have 4 or 6—but not this year!  Of course, this jay-a-palooza wouldn’t be complete without the marauding hordes of Pinyon Jays—75 at one count this weekend.  Do not get me started on those rowdy hooligans…

But let’s focus on scrub-jays.  A large, crestless jay with blue upperparts, the Western Scrub-Jay shows a gray mask, a gray patch on the back, a white throat with faint blue edging, a hint of a light eyebrow, and grayish underparts.  (Males and females can’t be distinguished very easily.)  Affectionately known as “scrubbies,” they tend toward noisy and social, usually arriving in small family groups.  They move easily on the ground and can also bound up the branches of a tree as if they had springs on their feet.  They can be confused with Pinyon Jays, if you have both in your area.  (And my sincerest sympathies, if you do.)  But Western Scrub-Jays have noticeably longer tails than Pinyon Jays do and Pinyons are more of a dusty blue overall.  Colorado’s scrubbies breed in pinyon/juniper habitats 3 times more often than the next runner up (scrub oaks), according to the Colorado Breeding Bird Atlas.  Throughout the American West, though, the Western Scrub-Jay is the familiar jay of a broad range of lowland and even lower montane habitats.

A scrub-jay’s diet runs the gamut and varies by season.  In summer, it eats a wide variety of insects, spiders, fruit, small rodents and herptiles, and even the eggs and young of other songbirds.  In winter, it shifts to acorns, seeds, nuts, and berries.  If you live in appropriate habitat and put feeders out with suet or sunflower seeds, scrubbies will visit—and, sometimes, pretty much just set up camp.

Scrub-jays mate for life although if a mate dies, he or she will quickly be replaced.  (As with most songbirds, scrubbies do not spend much time mourning.)  Once pairs form, breeders remain together to defend their territories year-round.  Although scrubbies generally announce their presence loudly and incessantly, they become shockingly silent when nesting.  Both adults work together to build their extremely well-hidden nest.  Incubated only by the female for about 15 – 17 days, a typical clutch contains 3 – 6 eggs.  Both parents feed the young, who remain in the nest for 18 – 20 days.  Juveniles depend on the adults for food and protection for a month or so after fledging.  With such a long “apprenticeship” period for the youngsters, most Western Scrub-Jays produce only one brood a year.  While they don’t migrate, family groups do generally disperse a bit by late winter because the new generation have to find their own territories.

Western Scrub-Jays bear the scientific name of Aphelocoma californica.  The genus name refers to the lack of a crest:  Aphelocoma means “smooth hair,” from the Greek apheles (meaning smooth) and kome (hair of the head).  The species name demonstrates that the prototypical bird was found in California (which also has the largest population in the U.S., at ~50%).  The common name arises from this species’ frequenting scrub-like habitats; “Western” distinguishes our Scrub-Jay from the Island Scrub-Jay (found only on Santa Cruz Island, California) and the Florida Scrub-Jay—all of which were once thought to be the same species.

Since they are members of the very intelligent Corvid family (along with crows and magpies), we shouldn’t be surprised that scrubbies have a mischievous streak.  They’ve been observed sneaking acorns from Acorn Woodpecker caches and stealing seeds and cones from Clark’s Nutcrackers.  They even seem to know that they could be both victim and perpetrator.  Researchers report that some have swiped food they’ve watched other jays hide. When these felons head out to hide their own food, they wait until the coast is clear to that make sure no other jays are watching.  It takes a thief to know a thief…

You can learn more about this species here.