December Bird of the Month: Blue Jay

Most regions of the country have their resident "Blue Jay," but "cristata" is the species officially designated by that name. It ranges through Canada and the United States east of the Rocky Mountains and is the only Jay species in much of our area.

White patches and black-and-white barring ornament the Blue Jay's blue wings and tail, while a black necklace crosses the whitish breast. Washington Irving described it as "That noisy coxcomb, in his gay light blue coat and white underclothes," while 19th century ornithologist Charles Bendire was more fascinated by its ever-changing personality: "Cunning, inquisitive, an admirable mimic, full of mischief; in some localities extremely shy, in others exactly the reverse, it is difficult to paint him in his true colors."

Blue jays roam woodlands, parks and towns in search of a variety of foods. One study found their summer diet to contain 30 percent insects and other invertebrates, as well as some small vertebrates; the other 70 percent was made up of acorns, fruits and seeds.

The Blue Jay's nest is a bowl of twigs and dry leaves high in a tree; the three to five eggs are blue or greenish spotted with brown. They hatch after 16 to 18 days of incubation by the female and the young fledge in 17 to 21 days more. It has a piercing call...jay, jay, jay...once described by Thoreau as the "unrelenting steel-cold scream of the jay, unmelted, that never flows into a song, a sort of wintry trumpet..."

The Blue Jay is responsible for planting trees, such as oak trees. Blue jays love acorns. They take acorns and hide them so they can come back to the acorns later. However, the Blue Jays often forget where they hide them. These hidden acorns later sprout into oak trees.

Although the migration of Blue Jays is an obvious phenomenon, with thousands moving past some points along the coast, much about it remains a mystery. Some Jays are present throughout the winter in all parts of the range. Which Jays move and which stay put? Although young Jays may be more likely to migrate than adults, many adults do migrate. Some individual Jays may migrate south in one year, stay north the next winter, and then migrate south again the next year.

Many people dislike the Blue Jay because it is known to eat the eggs and nestling's of other birds. However, in an extensive study of Blue Jay feeding habits, only 1% of Jays had evidence of eggs or birds in their stomachs. Most of the diet was composed of insects and nuts.

The Blue Jay frequently mimics the calls of hawks, especially the Red-shouldered Hawk. It has been suggested that these calls provide information to other Jays that a hawk is around, or that they are used to deceive other species into believing a hawk is present.

This link represents the Blue Jay call.

Comments

[Perry]

Interesting stuff, John. I didn't know they were mimics.

I have an oak tree, over 100 years old, in my yard, and tons of blue jays. Now I know why!

-Perry-

[Larry]

-I think Blue Jays are clever and interesting watch.This seems especially true when there's a large group of them together.The egg stealing/ stomach content statistic is interesting.--Larry