The Western scrub-jay is a medium-sized bird native to western North America. It has a blue head, wings, and tail, a gray-brown back, grayish underparts, and white eyebrows. The throat is whitish with a blue necklace. The Western scrub-jay doesn't migrate and can be found in urban areas, where it can become tame and will come to bird feeders.
Western scrub-jays are found from Washington State south through California and western Nevada near Reno to the west of the Sierra Nevada. They inhabit areas of low scrub, preferring pinon-juniper forests, oak woods, and edges of mixed evergreen forests. They can also be found in suburban gardens and backyards.
Western scrub-jays are social birds that are active during the day. They usually forage on the ground in pairs, family groups, or small non-kin groups, outside of the breeding season. Western scrub-jays store food in scattered caches within their territories and are able to recover the hidden caches even after long periods of time. In the process of collecting and storing this food, they often plan ahead in choosing cache sites to provide adequate food volume and variety for the future. Due to their accurate observational memories, these birds may steal food from caches made by other jays and may also steal acorns from acorn woodpecker caches. Western scrub-jays are playful and noisy in their nature. Their call or "screech" is described as "harsh and scratchy". They also utter loud and harsh quay-quay-quay calls.
Western scrub-jays are omnivores. They feed on small animals, such as frogs and lizards, eggs and young of other birds, insects, and (particularly in winter) grains, nuts, and berries. They will also eat fruit and vegetables growing in backyards.
Western scrub-jays are monogamous and form pair bonds that last for many years. They breed from March to April. To attract a female, the male performs a courtship display; he hops around her with erected head and fanned tail dragging. When the pair is formed, the female starts to construct the nest which is usually located low in trees or bushes, 1-10 m (3.3-32.8 ft). During the nest construction, the male guards the female from the nearest perch. The nest is sturdy, with an outside diameter of 33-58 cm (13-23 in), constructed on a platform of twigs with moss and dry grasses lined with fine roots and hair. The female lays 4 to 6 eggs with two common shell color variations: pale green with irregular, olive-colored spots or markings; and pale grayish-white to green with reddish-brown spots. The female incubates the eggs for about 16 days. The chicks are altricial; they hatch naked, helpless, and with eyes closed. The chicks start off fully gray. The older they get, the more they turn blue. On their heads, chicks tend to have a red crest that resembles a comb which they will lose on day seven. The young usually leave the nest about 18 days after hatching and remain with their parents for about five months. They become reproductively mature after about 1 year of age.
Western scrub-jays are common and not considered threatened. However, populations of this species suffer from disturbances and predation from domestic cats which are responsible for the death of large numbers of birds.
The IUCN Red List and other sources don’t provide the number of the Western scrub-jay total population size. According to the California Partners in Flight Oak Woodland Conservation Plan for the Western Scrub-Jay, the total population size of the species in Monterey County, California may exceed 20,000 pairs. Currently, Western scrub-jays are classified as Least Concern (LC) on the IUCN Red List and their numbers today are stable.
Western scrub-jays play a very important role in their ecosystem. They disperse seeds of various plants and fruits they consume in their diet when burying them in the soil for later consumption; if birds forget to return to this caches seeds will germinate.