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Spring 2013

Urban Jungle

The changing natural world at our doorsteps | Illustration and text by Patterson Clark      

May 28, 2013

Danger days for blue jays


In late May, blue jay fledglings begin leaving the nest, a step that inflames their parents with protective vigilance. Even the mildest person walking within a few yards of a youngster can invite a fearless attack from a parent jay.

With crest raised high in agitation, the jay mom or dad gains a high perch behind the perceived intruder. It may issue a deceptively sweet "bell call," which resembles the sound of a squeaky door hinge. The jay swoops down to beat the human's head with its wings, sometimes planting a peck or scrape to the scalp.

Perils of the nest

Blue jays have good reason to be protective. Only a little more than half of their nests produce at least one chick, thanks to the gray squirrels, crows and snakes that often prey on eggs and chicks.

Jays also have a persistent reputation of being nest pirates that eat the young of other birds, but a study of blue jay stomach contents revealed that only
1 percent of the birds had remnants of eggs or baby birds in their gut. Jays mostly eat nuts and insects, often delivering fat caterpillars to chicks in the nest.

Nests are usually 10 to 25 feet up, well hidden in the forks of deciduous or coniferous trees, although at least one currently active nest in Washington is built in a thick stand of bamboo. Fortunately for the chicks, squirrels tend to avoid bamboo.

Another advantage: Proximity to a building tends to boost the chances for nest success, possibly because human activity often keeps predators at bay.

But humans also harbor predators. Cats are the most frequent cause of death for young jays, so vigilant parent jays will dish the same fury unto kitty as they deliver unto Bubbah.

Parents don't encourage fledglings to leave the nest until they are 17 to 21 days old, but an ambitious baby may go exploring on its own, climbing out onto branches within a few yards of home. However, parents won't feed the truant until it grapples back to the nest.

Blue Jay fledgling, Cyanocitta cristata, illustration by Patterson Clark

Departure

When it's finally time to go, fledglings follow prompting from their folks and make their first clumsy flight. Two days later, most fledglings have ventured more than 75 feet from the nest. They will stick with their parents for a month or two before realizing independence. By next year, they will be ready to breed.

Finding a fledgling

People sometimes encounter fledglings and mistakenly think that the baby birds need rescuing. But wildlife experts advise a hands-off approach. Almost always, parent birds are nearby and are much better equipped at raising and protecting a young blue jay than humans.

However, if a fledgling on the ground is being stalked by a cat or is sitting in the middle of a busy street, an intervention may be appropriate. Place the bird in a small box lined with an old T-shirt and lodge it safely in a tree as close to where it was found as possible. (Touching the bird won't cause the parents to abandon it.) If parents fail to tend to the fledgling within a few hours, contacting a wildlife rehabilitator for guidance may be necessary. But watch your head — a parent may be closer than you think.

Sources: Journal of Avian Biology, The Auk, The Condor, The Wilson Bulletin, Cornell Laboratory of Ornithology, Texas Parks and Wildlife, University of Michigan Museum of Zoology, USDA, Life Histories of Familiar North American Birds