blue jay

blue jay, (Cyanocitta cristata), large North American member of the bird family Corvidae known for its primarily blue plumage, large feather head crest, and raucous call. The blue jay is found in coniferous and deciduous forests east of the Rocky Mountains in both the United States and southern Canada. It is an intelligent, adaptable species related to crows and ravens, and it has learned to coexist with people, living in cities and suburban residential areas, where it is infamous for its aggressive behavior at bird feeders. Most taxonomic systems recognize four subspecies: the northern blue jay (Cyanocitta c. bromia, which inhabits southern Canada and central and southeastern U.S.), the interior blue jay (C. c. cyanotephra, which lives in the southern Great Plains), the coastal blue jay (C. c. cristata, of the eastern U.S.), and the Florida blue jay (C. c. semplei, of southern Florida).

Natural history

The blue jay measures between 22 and 30 cm (8.7 to 11.8 inches) long and weighs between 65 and 109 grams (2.3 to 3.8 ounces), and it is named for its blue coloration. Blue jay feathers contain melanin, a brown pigment; however, the bird appears blue due to specialized cells on its plumage that reflect blue light. In addition to a blue back and head, the blue jay has a white breast and white markings on its wings, a white and gray throat patch, and a gray-blue crest. Black bars mark the tail, and the bird has a black collar that extends toward the throat from the rear base of the crest.

Blue jays are omnivores, and they feed in trees, in shrubs, and on the ground. A favorite food is acorns, which jays break open with their beaks to consume the seed inside. Their diet, which varies seasonally, also includes grains, sunflower seeds, fruits, and berries. They also consume live prey, such as insects, arachnids, snails, small rodents, and amphibians. A small percentage of blue jays consume eggs and young from other birds’ nests. Other sources of nutrients include carrion and pet food. Jays store foods for later consumption, and forgotten caches can sprout into new plants—especially oak trees, whose geographic range after the most recent glaciation was increased by this behavior. In addition, blue jays may mimic the vocalization of a hawk or another bird of prey to frighten another bird out of its meal. Blue jays, in turn, may become food for larger vertebrates, including domesticated dogs and cats. Nestlings may be taken by birds of prey, raccoons, crows, snakes, opossums, and squirrels, while adults can fall prey to hawks, owls, and falcons.

Beyond their convincing impressions of birds of prey, these songbirds can make a wide range of vocalizations. Although one of their best-known calls is a distinct, piercing jeer, they also make chattering sounds, squeaks, growls, and whistles. Some of their calls have even been described as sounding like a bell or a rusty pump handle.

Blue jays are monogamous, and they remain with their mate for life. The species’ courtship includes one bird chasing or feeding the other. Between March and July, both partners choose a site in a tree from 3 to 7.6 meters (about 10 to 25 feet) off the ground in which to construct a nest made of twigs, leaves, and other plant material. They may also daub the nest together with mud and decorate it with pieces of string, cloth, or paper. Blue jays may construct a new nest each year, reuse or repair a nest from a previous breeding season, or take over a nest built by another bird. Females generally lay four to five light blue, green, or buff-colored eggs in a clutch; the female typically incubates the eggs, while the male brings food to her, though males have also been observed incubating eggs. The eggs hatch in about 17 days, and both parents feed their young. The young birds learn to fly at 17–21 days; however, they often remain with their parents for up to three months before going off on their own. Young jays can begin to breed at age one. The birds typically live for about 7 years in the wild, but one lived to be about 26 years old in captivity.

Conservation status

The International Union for Conservation of Nature and Natural Resources (IUCN) classifies the blue jay as a species of least concern, owing to the bird’s vast geographic range and adaptability to multiple habitats, especially to those affected by human activities. Bird surveys note that blue jay populations are stable throughout their range, with some estimates reporting that the total population is as high as 17 million birds. There is evidence that their populations are sensitive to deforestation, habitat loss, and pesticide poisoning. Along with their close relatives, crows and ravens, blue jays are susceptible to the mosquito-borne West Nile virus; the birds can carry the disease before succumbing to its effects.