The passerine birds of the genus Aphelocoma include the scrub-jays and relatives. They are New World jays found in Mexico, western Central America and the western United States, with an outlying population in Florida. This genus belongs to the group of New World (or "blue") jays - possibly a distinct subfamily - which is not closely related to other jays, magpies or treepies (Ericson et al, 2005 ). They live in open pine-oak forests, chaparral, and cloudforests.
mtDNA NADH dehydrogenase subunit 2 sequence data (Rice et al. 2003 ) is unable to properly resolve the relationships of the species. Judging from New Wold jay biogeography, the Unicolored or Mexican Jays might represent the most basal lineage; morphology would tentatively lean towards the latter which retains more of the group's color patterns, while the available molecular data allows no robust conclusions whatsoever. In any case, the data of Rice et al. (2003) suggests - albeit also with very low confidence - that the Mexican Jay comprises 2 clades which might constitute different species. However, far too few individuals have been sampled to say anything definite on that matter, except that the lineages - if they indeed exist - do not correspond to the geographical pattern of intraspecific variation (see species article for more).
On the other hand, it is somewhat more likely that the Western Scrub-Jay is made up of 2 species. These would be separated by the Great Basin, with the Pacific coastal lineage ("California" Scrub-Jay) and the Island Scrub-Jay, as well as the inland lineage ("Woodhouse's" Scrub-Jay) and the Florida Scrub-Jay being sister species. This treatment fails to address the problem of birds from inland southern Mexico. What is known about the paleogeography of North America supports these findings, but they must be considered preliminary pending analysis of much more data (Rice et al. 2003 ). Nonetheless, it is actually because the molecular diversity pattern is so badly resolved that it supports the view that rapid Late Pliocene radiation of the North American Scrub-Jays led to the present diversity.
Aphelocoma jays are slightly larger than the Blue Jay and differ in having a longer tail, slightly shorter, more rounded wings, and no crest on the head. The top of the head, nape, and sides of the head are a rich deep blue. Some species have a white stripe above the eye and dark ear coverts. The breast is also white or grey-white and the back is a grey-brown contrasting with the bright blue tail and wings in most species. One species, Unicolored Jay, is blue all over, superficially similar to the Pinyon Jay from much further north. The bill, legs, and feet are black.
Wild Aphelocoma jays are frequent visitors at campsites and picnics and have frequently learned to eat from the hands of people where they have become accustomed to being fed.
The nest is in a tree or a bush, sometimes quite low down. The nests are compact and lined with hair and fine roots with an outer diameter of about 30cm to 60cm. Usually 2 to 4 eggs are laid and incubated over 14 to 16 days. There are two main variations of egg shell color: green with olive markings or a paler background of grayish-white to green with red-brown markings. The Florida Scrub-Jay and the Mexican Jay both have cooperative breeding systems involving several 'helpers' at each nest, usually siblings of the main pair.
Aphelocoma jays are quite vocal and have a huge range of sounds and calls; common calls include a cheek, cheek, cheek and a guttural churring krr'r'r'r'r. Aphelocoma jays are also, like all other jays, often quite aggressive at feeding areas, and sometimes regarded as a nuisance.
Reproductive Success, Territory Size, and Predation Pressures of the Florida Scrub-Jay (Aphelocoma Coerulescens) at Savannas Preserve State Park
Jan 01, 2005; Abstract The Florida Scrub-jay is found only in the fire-dependent xeric oak communities of Florida. The number of scrub-jays...