- Aphelocoma californica
Identification:
11-13" (28-33 cm). Robin-sized, but large strong bill and long tail make it appear larger. Head, wings, and tail blue (conspicuous when it glides in a long, undulating flight); back dull brown; underparts light gray. No crest; dusky face mask. White throat offset by incomplete blue necklace.
There are three distinct populations, with slight range overlap. Members of the Pacific population (group californica), shown in the photo by Leslie, have more vivid colors and markings than birds further east: darker blue in back, tail, and head, whiter underside plumage, and more distinct eyebrow and facial marking contrast. The Pacific bird is also bolder in behavior than interior birds. The interior birds (group woodhouseii) have a less contrasting breast band, and a straight bill that is thinner and lacks hook near the tip. The southern birds (group sumichrasti) are larger, have bluer backs and whiter throats (when compared with woodhouseii) and a hooked bill.
Distribution
Resident from Washington, Wyoming, Utah South of the Wasatch Front, and Colorado south to Texas; also in Mexico.
Taxonomy
Currently recognized are 15 subspecies falling in three main groups:
- group californica contain the largest number of subspecies and occur mainly west of the Rocky mountains including Baja California
- group woodhouseii is mainly east of the Rockies and also include several subspecies; overlaps with previous group in western Nevada (Pine Nut Mountains)
- group sumichrasti is an internal group limited to Mexico, and includes remota
These three groups have in the past been considered separate species, and may become full species again (especially the split between californica and woodhouseii seems likely).
Habitat
Group californica: scrub oak, woodlands, and chaparral, but does not breed in low scrub because it needs watch posts; also inhabits suburban gardens. The woodhouseii group has a preference for pinyon-juniper,
Behaviour
Nesting: 3-6 eggs, spotted on darker, greenish or reddish base, in a twiggy nest well hidden in a tree or dense shrub. Voice: Call is loud, throaty jayy? or jree? In flight, a long series of check-check-check notes. There are audible differences in vocalizations between the three groups.
Like all jays, this species may be secretive and silent around its nest or while perching in a treetop in early morning but is frequently noisy and conspicuous. Scrub jays often eat the eggs or young of other birds, but in summer they are mainly insectivorous. These birds also eat acorns and have been described as "uphill planters," counter-balancing the tendency of acorns to bounce or roll downhill. The jays bury many more acorns than they consume and help regenerate oak forests that have been destroyed by fire or drought.
References
- AOU proposal including a discussion of possible split of the three groups, read August 2009
- Clements, James F. 2007. The Clements Checklist of Birds of the World. 6th ed., with updates to October 2007. Ithaca: Cornell University Press. ISBN 9780801445019
