Cyanocitta stelleri
Steller's jay

Starting from the southern coast of Alaska, the range extends continuously southward through the Rocky Mountain region of the western United States into Mexico, and scatters through Central America, terminating in north-central Nicaragua. The western edge of distribution lies along the Pacific coast, and reaches eastward as far as eastern Colorado (Greene et al. 1998; National Geographic Society 1987).

Cyanocitta stelleri primarily reside within coniferous forests, though deciduous forests are also chosen. The altitude of habitat location ranges between 1000-3500 meters. Although C. stelleri are non-migratory birds, migration from high to lower elevation is known to take place during the winter season (Greene et al 1998; Kaufman 1996; National Geographic Society 1987; Terres 1980).

Adult C. stelleri average in length ranging from 30 to 34 cm., with a mass of 100-140 g. The wingspan varies from approximately 45 to 48 cm. Distinguishing characteristics include a black, thick, pointed bill typical of corvids. Coloration consists of dark blue/cobalt plumage throughout most of the body, including the wings, coverts and rectrices. The wings and rectrices also possess a pattern of black barring, perpendicular to the rachis of the feathers. The entire head is usually black, although certain subspecies such as C. stelleri macrolopha may have white streaks along the forehead and supercilium. Other races have even further deviations from typical C. stelleri plumage. Perhaps the most conspicuous characteristic of C. stelleri is the presence of a tall, black crest. Juveniles are distinguished by a sooty gray coloring on the head and body, as well as a shorter crest. The sexes are nearly monomorphic, with the exception of fainter and narrower bars in the barring pattern of females (Green et al. 1998; National Geographic Society 1987; Rue III 1970; Terres 1980).

The Steller's Jay is a highly social species. Flocks of various sizes form often, with mates rarely parting. As a consequence of frequent flock formation, C. stelleri have several forms of agonistic behavior. One form involves aggressive fighting while flying in the air. The two birds involved will fly upward, and attempt to grasp each other with the feet while pecking each other with their bill. Crest displays and an act called Aggressive Sidling are also used for establishing social status. Steller's Jays use wing spreading to express submission. Steller's Jays also use antipredator displays, with mobbing (gathering in large numbers to vocally harass and fly at predators)the primary form of defense. Typical predators include accipiter hawks such as Cooper's Hawks. Vocal communication is fairly complex, with calls including a harsh "shack, shooka" sound, and mimicry of a red-tailed hawk. The song consists of a moderate to soft warble (Greene et al 1998; National Geographic Society 1987).

Cyanocitta stelleri are omnivorous, with a diet consisting primarily of nuts, pine seeds and acorns. Like other corvids, Steller's Jays eat the eggs of other birds. Foraging takes place on the ground and within the trees. Scavenging is also known to take place, most of which occurs within developed areas and campgrounds. During winter, C. stelleri depend upon seeds and nuts, though they may also scavenge and even prey upon small invertebrates that happen to be active within the habitat at the time (Greene et al 1998; Kaufman 1996; Sieving et al 1999).

Since Cyanocitta stelleri are often observed scavenging at picnic and campsites within their habitats, there exists the possibility of being considered as a nuisance (Greene et al 1998; National Geographic Society 1987).

Cyanocitta stelleri do not have any strong economic/agricultural contributions, though their consumption of insects may have an impact on pest control.

Cyanocitta stelleri is neither endangered nor threatened according to any of the organizations involved with biodiversity and conservation.

Cyanocitta stelleri and the Blue Jay, Cyanocitta cristata, are a classic example of allopatric speciation, with the Rocky Mountain Range being the probable source of divergence. Hybrids have been known to occur along the central United States within the Great Plains region. The zone of hybridization is maintained through a "sink" mechanism known as dynamic equilibrium (Greene et al 1998).