Aphelocoma

The genus Aphelocoma was introduced in 1851 by the German ornithologist Jean Cabanis. He placed four species in his new genus but did not specify the type. In 1858 the American naturalist Spencer Baird designated the type as Garrulus californicus Vigors, 1839, the California scrub jay. The genus name combines the Ancient Greek αφελης/aphelēs meaning "smooth", "sleek" or "simple" with κομη/komē meaning "hair". The species in this genus 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. Phylogenetic analysis based on mitochondrial DNA sequences suggests three clades within the genus: the unicolored jays, scrub jays, and Mexican jays. Relationships among these clades are incompletely resolved, but suggest that the unicolor jays are sister to the remaining two clades. The genus contains seven species: ==Description==

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, the unicolored jay, is blue all over, superficially similar to the pinyon jay from much further north. The bill, legs, and feet are black. ==Behavior==

The diet consists mainly of acorns and pine nuts. However, grain, berries, and other fruits are often eaten as well. These birds can also be omnivorous; their diet can include insects, eggs and nestlings, small frogs, mice, and reptiles. As food-storing birds, the scrub jays demonstrate a unique episodic memory. They can find their food hiding places with great precision, even several days after the initial cache. 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 30 cm to 60 cm. Usually two to four 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 relatives of the breeding pair. Increased prolactin in the breeding pair leads to the expression of parental behavior and physiology. The source of the alloparental behavior found in helper birds has been the focus of many studies. A positive correlation was found between increased prolactin levels during the breeding period and helping behavior in non-breeding Aphelocoma jays. Scrub jays are members of the family Corvidae, which are considered the most intelligent of the birds and among the most intelligent of all animals. 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, antagonistic at feeding areas and sometimes regarded as a nuisance. ==References==