Western scrub-jays are usually 29.21 cm long, from the tip of their beak to the end of their tail. They can weigh between 70 to 100 g, although they average 85 g. Males of this species are usually bigger than females. These birds are brown, gray, white, and blue. They have fairly long beaks and tails. Their forehead is blue with white eyebrows and they have gray or black around their eyes. Their breast, sides, and belly are gray or white and the base of their neck is brown or black. On their wings, their primary and secondary feathers are blue. Western scrub-jays look different than other jay species because they do not have a crest or white on their wings, likewise, they are the only jays with their specific color combination. (Curry, 2002; Sibley, 2003; Stokes, 2013)
Western scrub-jays (Aphelocoma californica) are found in western North America. They can be found from the West Coast of the United States, north to northern Oregon, south to dry, southern areas of Mexico, and east to central Texas. These birds do not migrate, but during the winter months they may move to the lowland edges of their range. (Curry, 2002; Delaney, et al., 2008)
Western scrub-jays are often found in very dry, open, hot coastal areas. They are often found near large populations of humans. They can live up to 3,700 m in elevation, but they are usually found in lower elevation areas with thick grass and low shrubs. These birds are often found in dense forested areas. (Curry, 2002; Ramamoorthy, et al., 1993; Sibley, 2003; Woolfenden, 1985)
Western scrub-jays form monogamous breeding pairs, where each bird only mates with one other bird. To attract mates, males show off by preening their feathers, this involves using their bill to clean lice and other insects from their feathers. Preening helps them stay healthy and increases their chances of mating. Males usually establish a territory and build a nest in March. To court females, males sing a series of soft-pitched tones. (Clayton, 2002; Curry, 2002; Vleck and Brown, 1999)
Western scrub-jays breed from March to April. In many cases, these birds only have one brood per year, but if a brood is unsuccessful, they may try again. They usually lay 3 to 6 eggs that hatch in about 18 days. When they hatch, chicks usually weigh 5.6 to 7.5 g. After 16 to 26 days, western scrub-jays enter their fledgling stage, which means they are ready to leave the nest. These birds are physically ready to mate after about a year, however, until males are able to defend a territory, females will not mate with them, these males are considered 'floaters'. They can stay in their 'floating' stage for up to 7 years. (Carmen, 2004; Curry, 2002)
After a male finds a mate, he builds a nest before mating. Nests are made from plant material and twigs, as well as horse and cow hair. Females cover their chicks after they hatch. Nestlings usually eat moth or butterfly larvae and acorns. Males keep their nest clean by removing waste while the nestlings develop. (Curry, 2002)
In the wild, the longest lifespan for this species is 15 years and 9 months, while in captivity, this species has survived up to 19 years and 8 months. A study in Monterey County, California found about 65% of birds survived their first year, but only 13% survived to their second year and only one bird lived past 5 years. (Clapp, et al., 1983; Linsdale, 1949; Vandersande, 2002)
Western scrub-jays use a gliding flight, but move their wings more when they spot a prey item, or when they are trying to avoid a predator. When they are on the ground, western scrub-jays travel by hopping. Like other jays, these birds are diurnal, social, and rather vocal. Males defend territories during the breeding season and form social hierarchies based on the quality of their territory. When western scrub-jays find a dead member of their species, they call other jays to the spot by making loud calls. (Carmen, 2004; Curry, 2002; Iglesias, et al., 2012; Sibley, 2003)
Western scrub-jays communicate in several ways. If they see a dead western scrub-jay on the ground, they react by flying from tree to tree and making loud screams, when they do this, other nearby western scrub-jays also begin vocalizing. They also have a specific vocalization for finding a mate. Western scrub-jays sing to possible mates in a sequence of tones with a soft pitch. Likewise, western scrub-jays use a specific call to defend their territory from an outsider. While resting on a branch, they make loud, repetitive screams from low to high pitch while raising their bill in the air. By using their sense of sight and smell, they are able to determine the food quality of the seeds they find. (Curry, 2002; Iglesias, et al., 2012)
Western scrub-jays are omnivorous. Depending on the time of year, these birds eat plant or animal material. From October to February, they mostly eat acorns and from May to June they mostly eat fruit. They are most likely to eat animal matter during the month of April. Western scrub-jays eat fruits, mainly cherries and prunes, as well as other grains and vegetables such as oats and corn. These birds also eat insects including beetles, bees, moths, grasshoppers, and planthoppers. Western scrub-jays may prey on animals including small birds and their eggs, amphibians such as California slender salamanders, and reptiles such as western fence lizards. Depending on where they live, their bills have different shapes to help feeding. Jays found in areas with dense oak trees have deep, hooked bills, which helps them eat nuts. Jays found in areas with dense pinon pines have a more pointed bill, which helps them open pinon cones. They usually hide seeds in the ground, but they may also hide them under rocks or on top of telephone poles and cover them with leaves. (Clayton, 2002; Curry, 2002; Dunn and Tessaglia-Hymes, 1999)
Western scrub-jays use high-pitched vocalizations when they feel threatened by predators such as raccoons, long-tailed weasels, western spotted skunks, striped skunks, western gray squirrels, fox squirrels and a host of snake and bird species. Common avian predators include American crows, Cooper's hawks, sharp-shinned hawks, golden eagles, red-tailed hawks, and prairie falcons. (Clayton, 2002; Curry, 2002)
Western scrub-jays help disperse seeds throughout their habitats. They disperse seeds from a variety of oak, pine, and juniper species, specifically Colorado pinon pines, and bury them to eat them later. If, however, they do not return, the seeds have a chance to germinate. These jays also host lice species including Philopteras cassipes, Brueelia deficiens and Myrsidea species. Western scrub-jays form mutualistic relationships with Columbian black-tailed deer by eating ticks, hippoboscid flies (keds or louse flies), and deer flies from the deer's skin. (Bush, et al., 2009; Clayton, 2002; Francis, et al., 2012; Isenhart and Desante, 1985)
Humans often provide food for western scrub-jays, especially during winter months when less food is available. This can be pleasant for bird-watchers and beneficial to bird seed sales. These birds have also been researched to develop a better understanding of their role in their habitats. (Francis, et al., 2012; Jones and Reynolds, 2008)
Western scrub-jays currently have a stable population and are not endangered. However, 5,283 western scrub-jays have died over an 18-year period due to wind turbines. These jays are also found in areas with large populations of humans and domestic cats. Sadly, cats kill billions of birds in the United States every year. (Curry, 2002; Milius, 2013)
Jimmy Scott (author), Radford University, Karen Powers (editor), Radford University, Leila Siciliano Martina (editor), Animal Diversity Web Staff.
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