Island Scrub-JayAphelocoma insularis

adult
Joe Fuhrman/VIREO
adult
Joe Fuhrman/VIREO
Island Scrub-Jay

Description

13" (33 cm). Similar in overall appearance to the crestless Western Scrub-Jay, the Island Scrub-Jay is approximately 15% larger in size with darker blue head, wings, and tail. Back dark brown; black cheeks set off from blue of head by narrow white eyebrow; white throat delineated by blue breast band from dusky breast and belly; undertail coverts bluish.

Voice

No advertising song; vocalizations similar to those of Western Scrub-Jay, although generally louder and harsher than among mainland birds. Most common calls a harsh shek-shek-shek or rising shreeenk.

Listen

calls #1
calls #2
calls #3
rattle (repeated twice)

Habitat

Oak woodlands, chaparral, dry scrub and pine forest.

Range

Endemic to Santa Cruz Island (where Western Scrub-Jays have never been recorded), approx. <40 km south of Santa Barbara. The island is the largest (250-km2) and most topographically diverse of California's Channel Islands. Scrub-Jays have probably been isolated on Santa Cruz Island for an estimated 28,000-125,000 yr.

Discussion

Island Scrub-Jays are the most distinctive member of the Channel Islands avifauna, and one of California's two endemic species (the other being the Yellow-billed Magpie). Year-to-year population fluctuations likely influenced by acorn availability. Unlike Western Scrub-Jays, population regularly includes 1-3-year-old non-breeding individuals; unlike Florida Scrub-Jays, these non-breeders do not assist breeding pairs in territorial defense or nesting activities.

Nesting

Nest a large bulky cup of twigs usually placed 2-3 m high in dense bush or tree; similar to nest of Western Scrub-Jay. Average clutch size (3.7 eggs) slightly smaller than that of Western Scrub-Jay populations on the adjacent mainland (4.1 eggs). Eggs light bluish-green with faint olive dots.

Similar Species

adult (Interior)

Western Scrub-Jay

11-13" (28-33 cm). Robin-sized, but large strong bill and long tail make it appear larger.

adult

Florida Scrub-Jay

11" (28 cm). Robin-sized, but large strong bill and long tail make it appear larger.

adult, Pacific NW

Steller's Jay

12-13 1/2" (30-34 cm). The only western jay with a crest. Front half of bird sooty black, rear dark blue-gray, with tight black crossbarring on secondaries and tail.

Vireo

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