Aphelocoma

The passerine birds of the genus Aphelocoma include the scrub jays and their 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. They live in open pine-oak forests, chaparral, and mixed evergreen forests. Seven species of Aphelocoma are generally recognized at the present time. They are believed to have evolved in the Pleistocene, and the Florida scrub jay is known to have been recognizably distinct and present in its current range for at least two million years. The inland, coastal, and Santa Cruz island populations of the (former) western scrub-jay are now considered three separate species: Woodhouse's, the California and the island scrub jays. Two different populations of the Mexican jay might similarly represent two separate species. mtDNA NADH dehydrogenase subunit 2 sequence data is unable to properly resolve the relationships of the species. Judging from New World 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 two clades which might constitute two separate 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). The western scrub-jay is now made up of three 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), with the Florida scrub-jay being a sister species.