The Island Scrub Jay (Aphelocoma insularis) is a conspicuous corvid endemic to Santa Cruz Island in the Santa Barbara Channel. Though similar in appearance, A. insularis is distinguished from it's mainland relative, the Western Scrub Jay (Aphelocoma californica), by a larger overall size, longer bill, broader skull, longer tarsi (Isitt 1989) and bolder coloration. Like its relatives, the Island Scrub Jay is omnivorous with a diet consisting of arthropods, seeds (particularly acorns), and some vertebrate animals such as lizards (Atwood 1978, Curry et. al. 2002). The Island Scrub Jay is territorial, though approximately 50% of the adult population consists of nonterritorial and nonbreeding "floaters" (Kelsey and Collins 2000). Its prime nest-building habitat consists of Quercus dominated chapparal (Atwood and Collins 1997), but it may also be found occupying less optimal habitat such as thickets of Mule Fat (Baccharis salicifolia) and groves of invasive Eucalyptus spp. (Atwood et. al. 1990). Mating pairs are monagomous and may remain together for several years with separation of the pair usually being the result of the death of one (or both) members (Atwood 1980). Nests are constructed by both sexes and consist of twigs and rootlets (Beck 1899) and are believed to be single-use (Atwood 1980). Eggs are ovate with an incubation period of 18 days (Baicich and Harrison 1997). Little information is currently available regarding how much time fledglings remain with parents. The IUCN lists this species as Near-Threatened (NT) due to its moderate susceptibility to stochastic events.
- Atwood, J. L. 1978. Breeding biology of the Santa Cruz Island Scrub Jay, Aphelocoma coerulescens insularis. Master's Thesis. California State Univ. Long Beach.
- Atwood, J. L. 1980. Breeding biology of the Santa Cruz Island Scrub Jay. Pages 675-688 in The California Islands: proceedings of a multidisciplinary symposium. (Power, D. M., Ed.) Santa Barbara Mus. Nat. Hist. Santa Barbara.
- Atwood, J. L. and C. T. Collins. 1997. The Island Scrub-Jay: origins, behavior, and ecology. Birding 29:476-485.
- Atwood, J. L., M. J. Elpers, and C. T. Collins. 1990. Survival of breeders in Santa Cruz Island and mainland California scrub jay populations. Condor 92:783-788.
- Baicich, P. J. and C. J. O. Harrison. 1997. A guide to the nests, eggs, and nestlings of North American birds. Academic Press, San Diego, CA.
- Beck, R. H. 1899. Nesting of the Santa Cruz Jay. Condor 1:6.
BirdLife International 2008. Aphelocoma insularis. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2.
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- Curry, Robert L. and Kathleen Semple Delaney. 2002. Island Scrub-Jay (Aphelocoma insularis), The Birds of North America Online (A. Poole, Ed.). Ithaca: Cornell Lab of Ornithology; Retrieved from the Birds of North America Online: http://bna.birds.cornell.edu/bna/species/713
- Isitt, J. J. 1989. Evolution of the Scrub Jay, Aphelocoma coerulescens in the western United States. Master's Thesis. California State Univ. Long Beach.
- Kelsey, R. and C. T. Collins. 2000. Estimated population size of the Island Scrub-Jay Aphelocoma insularis. Bird Conserv. Int. 10:137-148.