By Lee FranksDuring Vitus Bering’s ill-fated 1740-1742 expedition, the ship St. Peter spent only one day anchored off Kayak Island, near present-day Cordova, Alaska, before heading back to Siberia. The ship’s naturalist, Georg Wilhelm Steller, spent that July day in 1741 frantically collecting specimens and observing wildlife on the island. He was impressed with a black-crested, blue jay common on the island, but did not recognize it from the boreal forests of the Old World. Its similarity to the painting of the Blue Jay that he had seen in Mark Catesby’s 1731 portfolio “The Natural History of Carolina” convinced Steller that the expedition had reached America. Although Steller’s specimen was lost when the expedition was later marooned on Bering Island, his field notes describing the bird made it back to St. Petersburg where J. F. Gmelin used them to formally describe “Steller’s Jay“ in 1788.
Steller’s Jay, Cyanocitta stelleri, is a conspicuous, crested jay of western coniferous and mixed-coniferous forests, breeding from Alaska, western Canada, and the United States south through western Mexico to Nicaragua. With a crest unmatched by any other North American song bird and delicate blue hues sparkling in its plumage, this bird is as striking as it is extroverted and mischievous. It is less known to most North Americans than the familiar Blue Jay, and eastern birdwatchers often visit California to observe it.
Steller’s Jays travel throughout the eastern sections of the Park in loose flocks in August and September, and it is interesting to watch them fly directly to their destination in single-file. They noisily announce their arrival with their shack-shack-shack call. Habituating readily to humans, Steller’s Jay is well known in the picnic areas of the Park, where its loud, often raucous calls announce its presence.
Blue overall, with a jet black crest, throat, and upper breast. Black bars on wings and tail. A whitish line over the eye and faint, whitish streaks on forehead and throat. They are about 11.5 inches long, and the plumage of the sexes is similar. The only other crested jay in the United States and Canada is the Blue Jay, which is distinguished from the Steller’s by its uniform blue forehead, crest, and back.
BehaviorThey hop while on the ground, and climb trees by hopping from branch to branch, spiraling near the trunk. Their flight is strong and deliberate, but not sustained for long distances. Their social interactions involve complex combinations of postures, movements, crest displays, and vocalizations. Erectile crests are used as social signals in many different social contexts, and in combination with other postures, such as wing-spreading and tail-flicking. The crest is generally depressed when the bird is at rest, foraging or preening. Higher crest angle indicates greater aggressive arousal or stress. The crest becomes fully erect during high-intensity fights and predator-mobbing.
Steller’s Jays are socially monogamous. The male closely guards his mate during fertile periods. Pairs remain together throughout the year. They are highly social, with frequent interactions and displays among neighbors and small groups. In spring and fall, large flocks may form.
Steller’s consume a wide variety of animal and plant food, including arthropods, nuts, seeds, berries, fruit, small vertebrates, and eggs and young of smaller birds. Mast seeds, such as acorns and pine seeds, are important food sources when available. In our picnic areas, they consume a wide variety of foods, including peanuts, meat, cheese, bread, and cookies.
They forage on the ground and in trees and bushes. About 70% of total foraging time is spent in trees, with peak use in spring and fall. Foraging on the ground seems to increase in summer and winter. They typically carry nuts or large food items to elevated perches, then hold food items under one or both feet and strike them with a slightly open bill. They will cache food such as acorns by pushing them into crevices in the ground or in the bark of trees. Soil is loosened with the bill, sometimes digging a small hole, inserting a single food item in the hole and then covering the hole with soil or vegetation using their bill.
Courtship begins in March or April, with nest building peaking in April. Nest site appears to be selected by both members of the pair. Nests are typically placed on horizontal branches close to he trunk, often close to the top of a tree. Although both sexes participate in nest-building, the female contributes the most. Pairs often fly together to gather nest material, consisting of plant fibers, dry leaves, moss, and sticks. They will mix in some mud and line the nest with rootlets, pine needles and animal hairs. A typical clutch size is 4-5 eggs which are incubated for 16 days. Both sexes feed the young, which remain in the nest for about two weeks. Both parents continue to feed the young for about a month after they leave the nest. These dependent fledglings which beg loudly and chase parents, are capable of weak flights at age 15-22 days. Sustained flights occur at about 30 days of age.
The Birds of North America, No 343, 1998; Erick Greene, William Davison, and Vincent Muehter.
Dr. Lloyd Glenn Ingles © California Academy of Sciences.