Bird Profile

California Scrub-Jay

The blue, crestless, extremely confident jay of West Coast yards. It buries thousands of acorns a year, remembers where most of them are, and will learn your peanut schedule within a week.

The California Scrub-Jay (Aphelocoma californica) is the blue, crestless, long-tailed jay of oak woodland, chaparral and suburban yards along the Pacific slope, roughly 11 to 12 inches (28 to 30 cm) long. Blue head, wings and tail, a gray-brown saddle on the back, a white throat framed by a blue chest band, and a bold white eyebrow over a dark cheek.

If it has a crest and looks almost black in front, you are looking at a Steller's Jay instead. Those are the two common backyard jays over most of California, Oregon and western Washington, and they are easy to separate once you know that only one of them has a crest.

This profile covers the 2016 species split that makes older field guides confusing, how scrub-jays cache acorns on an industrial scale, the feeder setup that keeps them happy without letting them empty everything, and what they do the rest of the year.

How to identify a California Scrub-Jay#

Start with shape. This is a slim, long-tailed bird with a heavy straight bill and a flat head. No crest, ever. In flight it looks front-heavy and flaps in bursts with a swooping, undulating finish.

Then color. The head, wings and tail are deep azure blue. The back carries a distinct gray-brown patch, so the bird looks blue with a saddle rather than blue all over. Underneath it is pale gray, with a white throat outlined by a blue necklace that is usually complete or nearly so across the chest. A white stripe runs above the eye and a dusky mask through it.

Males and females look alike. Juveniles in summer are duller and grayer on the head and can look like a completely different bird for a few weeks.

Confusion species#

The 2016 split, and why your field guide disagrees#

Until 2016 the American Ornithological Society recognized a single species called the Western Scrub-Jay across the whole West. It was then split into the California Scrub-Jay of the Pacific slope and the Woodhouse's Scrub-Jay of the interior. Guides printed before that date, and a lot of old checklists and yard notes, still use the combined name.

The practical dividing line runs down the Cascade and Sierra Nevada crest, with a narrow contact zone in northern California and southern Oregon. West of it, in the Central Valley, coast ranges and Puget lowlands, you have California Scrub-Jays. East of it, through Nevada, Utah, Colorado, Arizona, New Mexico and west Texas, you have Woodhouse's.

The birds themselves look the part. California Scrub-Jays are saturated blue with a strong white throat and a stout, slightly hooked bill suited to hammering acorns. Woodhouse's Scrub-Jays are grayer and flatter in tone with a thinner bill better matched to pinyon pine seeds.

Where and when you will see them#

California Scrub-Jays are year-round residents and do not migrate. A pair holds a territory of a few acres for life and both birds stay on it through winter, so the jay on your fence in January is the one that nested down the block in April.

Their habitat is oak woodland, chaparral, riparian scrub, orchards and above all suburbs. Scrub-jays are among the birds that have gained from human landscaping: yards with oaks, ornamental berries, open lawn and scattered shrubs suit them nearly perfectly. They are common through California and up through the Pacific Northwest lowlands, where the species has spread north into the Puget Sound region over recent decades.

You will hear them before you see them. The usual call is a harsh rising shreeeenk, given in series, plus a dry rattle from females.

What they eat and the feeder setup that works#

The year splits in half. From spring through summer scrub-jays hunt insects and other small prey: grasshoppers, caterpillars, beetles, spiders, occasional lizards, and the eggs and nestlings of other birds. From late summer onward they switch hard to acorns and other nuts and seeds.

At a feeder they want big items they can carry.

Use an open surface. A platform or tray feeder or a wide deck rail works; a tube feeder does not, and a scrub-jay that cannot land properly will simply hang off it and knock seed to the ground. A dedicated peanut feeder with a wire mesh slows them down and makes the show last longer.

Acorn caching and a very good memory#

A single scrub-jay may bury several thousand acorns in one fall, carrying them one or a few at a time and pressing each into soil, leaf litter, lawn or a crack in bark. It does not use a larder. Each item goes in its own spot, and the bird relies on spatial memory to find them again over the following months.

That memory has made scrub-jays one of the most studied birds in animal cognition. Work on caching jays has looked at whether they remember what they hid, where, and how long ago, and at how they behave when another jay is watching: birds that have stolen caches themselves are more likely to move their own food once observed. Treat the details as an active research area rather than settled fact, but the caching itself is easy to watch from a kitchen window.

The ecological upshot is that scrub-jays plant oaks. The acorns they fail to recover are buried at exactly the right depth to germinate, which is why oak woodland and this bird are so tightly linked. If you want to give something back, native plants that include a local oak are the single most useful thing in a western yard.

Behavior worth knowing#

Boldness. Scrub-jays approach people closely, will take peanuts from a hand within a few weeks of regular feeding, and are quick to exploit picnic tables and outdoor cafes.

Tick picking on deer. Scrub-jays have been repeatedly documented landing on the backs of mule deer and picking ticks off them, with the deer standing still and even posing for it. It is uncommon to witness but well recorded.

Group gatherings around dead jays. When a scrub-jay finds a dead scrub-jay, it often calls loudly and draws in others, which gather and call for several minutes before dispersing. It looks funereal, and functionally it appears to work as a warning about a dangerous place.

Anting and bathing. They bathe hard and often. A shallow bird bath with a rough bottom gets used daily in dry weather.

Nesting#

Pairs build a bulky cup of twigs lined with fine rootlets and hair, usually 5 to 15 feet (1.5 to 4.5 m) up in a dense shrub, oak, or ornamental such as juniper or ceanothus. Both birds build.

Clutches are typically 3 to 6 pale green eggs blotched with olive. The female incubates for roughly 17 to 19 days, both parents feed the young, and chicks leave the nest around 18 days after hatching. One brood a year is normal.

Unlike the Florida Scrub-Jay, this species does not breed cooperatively. Pairs nest alone and drive off other jays, and young disperse rather than staying to help.

Population and conservation#

California Scrub-Jays are common and their numbers are broadly stable, helped by suburban planting across their range. They carry no conservation designation of concern.

The genuine threats are the ones all corvids face. West Nile virus hit jay populations hard after it arrived in the West in the early 2000s, and outdoor cats take a steady toll on fledglings that spend their first days low in shrubs.

A scrub-jay setup that works#

• Whole peanuts on an open tray, refilled at the same time each morning, 30 feet (9 m) from the small-bird feeders.
• A second tray or ground area with black oil sunflower and a little cracked corn.
• A sturdy suet cage for winter, mounted where a heavy bird can brace against something solid.
• Water, shallow and rough-bottomed, cleaned every few days.
• An oak if you have room for one. It is the whole reason this bird lives where it does.