The western scrub-jay (Aphelocoma californica), a member of the corvid family, is found throughout most of the western United States. Western scrub-jays are medium-sized songbirds weighing 80-100 grams and measuring about 28cm in length. Males and females have nearly identical blue and grey plumage and may appear indistinguishable, but in fact they are sexually dimorphic—males are generally larger than females and have more brightly colored feathers, although only slightly so. A small hook used for tearing flesh can be found on the tip of their bills and varies in size depending on region and diet.
Like many corvids, scrub-jays occupy diverse habitats such as chaparral, riparian, and woodland. And like all corvids, they are omnivorous In the Bay Area, their diets consist of acorns and other nuts, fruits, carrion, eggs, nestling and fledgling birds, small reptiles, small mammals, insects, and many anthropogenic foods such as those found at bird feeders and garbage dumps. Scrub-jays are one of the least social corvids and as such they do not usually feed in flocks. In fact, around food they tend to be just as aggressive towards conspecifics as they are towards other species. Like other corvids, jays cache food during the spring and summer and return to these stores during autumn and winter if other food is in short supply.
Western scrub-jays, like all corvids, form long term bonds with their mates, though when a mate is lost he or she is usually replaced quickly. There are also reports of extra-pair mating and even ’divorce’. Scrub-jays are non-migratory and mated pairs defend their territory year-round.
Being highly intelligent social animals, young western scrub-jays learn much of their behavior from their parents, and will remain with them until they are about three or four months old before dispersing. Corvids have a larger brain to body size than any other family of birds, comparable to that of dolphins and, by some reports, chimpanzees. In comparison to overall brain size the hyperstriatum—the region of the avian brain responsible for intellect—is larger in corvids than in any other group of birds. Added to that, corvids have a higher density of brain cells than any other bird.
Jays are highly active, enjoy play, have diverse vocalizations, exhibit amusing food caching antics, and, like all corvids, are a pleasure to watch.
Savage, C. (1995). Bird brains. San Francisco: Sierra Club Books.
Sibly, D.A. (2000). The Sibley guide to birds. New York: Alfred A. Knopf.