Two Jays, from East and West

Scientists still have a lot to learn about these bold birds

By Pat Leonard

Blue Jay by Elena Petrcich;
Steller?s Jay by Derrick Ditchburn

They're bold, brassy, and blue. The only two crested jays in North America are the Steller's Jay west of the Rockies and the Blue Jay to the east. They are hard to miss. Both belong to the genus Cyanocitta and exhibit a fondness for backyard feeders and a cocky, rock-star attitude.

To gauge a jay's mood, you need only look at its crest. Standing erect, it signals an aggressive or stressed bird—and one that may be headed for a fight. Jays are part of the noisy Corvidae family, which includes crows, ravens, and magpies. They can live up to 15 years.

Steller's Jays in the United States and Canada have black crests and black or gray backs. In central Mexico and Central America, they are smaller and have a blue crest and a blue or gray back. The Blue Jay has a blue crest and back, white or whitish gray throat and underparts, black band framing the head, and white wingbar. The jays' bright blue color comes from light refraction caused by the structure of the feathers, not from blue pigment.

Thanks to human development and backyard feeders, the eastern species has been jay-walking westward. Beginning in the 1970s, the Blue Jay's range expanded dramatically; now and then they even turn up as far west as Oregon and British Columbia. In areas where they overlap with Steller's Jays, the two species occasionally hybridize.

Even though jays are widespread and common, surprisingly little is known about their basic breeding biology and movements. They have complex social behaviors and communication. Males and females of both species form long-term monogamous pairings. Though some jays remain on their territory year-round, Steller's Jays that breed at high elevations usually move to lower ground over the winter. The migrations of Blue Jays are poorly understood. Some travel, whereas others remain in the same place year-round.

The Blue Jay is best known for its squawks and jeers, the Steller's Jay for its characteristic shack notes. According to The Birds of North America Online, both species are good mimics, copying the vocalizations of everything from squirrels and hawks to squeaky doors and telephones. They gang up on predators and drive them off with loud wah calls. When they're feeling mellow, both species even mutter a quiet little song.

Jays are big on storing nuts for the winter. A study of six Blue Jays outfitted with radio transmitters found that each bird stashed anywhere from 3,000 to 5,000 acorns in one autumn! Sometimes they even remember where they have buried their treasure, though this remains a topic ripe for scientific study. Though jays have a reputation for stealing eggs from other birds, one study found that the stomach contents of only 6 of 530 jays had any evidence of eggs or nestlings.

Bird watchers sometimes notice Blue Jays "anting," rubbing their wings with ants, spreading a substance the insects secrete, and often losing their balance and falling over in the process. Scientists don't have a convincing explanation for this intriguing behavior yet, though they have suggested the secretions could help clean the feathers or soothe skin irritated by the molting process. Some have hypothesized that the secretions repel feather parasites, but experiments so far haven't found the evidence.

They may be one of the most familiar visitors to our yards and parks, but behind that cocky attitude is a jay bird we need to get to know better.

Seeing jays at your feeders? Send your counts to Project FeederWatch. For more information, visit www.birds.cornell.edu/pfw.

For permission to reprint all or part of this article, please contact Laura Erickson, editor, Cornell Lab of Ornithology, 159 Sapsucker Woods Rd., Ithaca, NY, 14850. Phone: (607) 254-1114. email: lle24@cornell.edu