About Calocitta colliei (Vigors, 1829)
Calocitta colliei (Vigors, 1829) measures 58.5 to 76.5 cm (23.0 to 30.1 in) in total length, with over half of this length consisting of the tail. Individuals weigh between 225 and 251 g (7.9–8.9 oz). Only a small number of other corvid species, including the black-billed magpie, red-billed blue magpie, and the closely related white-throated magpie-jay, have a tail length comparable to this species. The species' upperparts are blue, with white tips on the tail feathers, while its underparts are white. Its bill, legs, head, and prominent crest are black, with the exception of a pale blue crescent marking above the eyes and a patch of pale blue below the eye. Juvenile individuals have a white tip to their crest, and their under-eye patch is smaller and darker blue than that of adults. For most birds of this species, the throat and chest are also black, but some individuals from the southern portion of the species' range have varying amounts of white on these areas. The calls of Calocitta colliei are varied, loud, raucous, and sometimes similar to the calls of parrots. This species occurs in pairs or small groups. It inhabits woodland (excluding humid woodland) and partially open areas on the Pacific Slope of Mexico, ranging from southern Sonora south to Jalisco and northwestern Colima. The total area of its native range is 160,000 km² (62,000 sq mi). As of 1993, there was some evidence that the species' population was declining. By 2013, the species had become established in southern San Diego County, California, particularly in the Tijuana River Valley. The established birds are likely descendants of escapees from nearby Tijuana, Baja California, where bird trade is unregulated.
