Blue Jay: Backyard Enigma

A blasting jeer comes from a blue jay in the big oak. Smaller birds scatter, except for a downy woodpecker, who freezes motionless on a tree trunk. A sharp-shinned hawk glides silently into my yard. It settles on a branch, watching for some small bird it can seize. It might have caught one, except that the blue jay ratted it out.

The blue jay may only have meant to warn other jays, but all the other birds understood perfectly. The feeders are suddenly bare, and the downy woodpecker that did not fly holds so still that it’s almost invisible. I wonder if it’s even breathing. The sharpie won’t catch a bird this time.

Blue Jays at Sport

Walking in the woods on a winter afternoon, I hear a great ruckus of cawing in the distance, too high-pitched for crows. Coming to an opening, I see a crowd of blue jays in the air above the top of a bare tree. Jays are diving down into the branches, and others are springing up, as if the whole bird mass were at a fast boil.

I know what it means. The jays have discovered an owl in its day roost. A few feet below the top, an unfortunate barred owl hunches in the branches, eyes almost closed, as if trying to ignore its tormentors. Maybe my approach puts the owl over the top, for it breaks out of the tree and hurtles toward a thicket of oaks that are still clothed in dry leaves. The jays follow, a screaming blue streamer behind the brown owl, until it buries itself from view in the oaks. The jays don’t follow into the depths of the trees but perch on top, still cawing and yodeling, as if celebrating their team’s victory.

Blue JayFamily Life and Social Structure

Even nonbirders know a blue jay when they see one. It’s a bird found in backyards all over eastern North America. Yet, few ethologists have studied its social life, and most of blue jay society remains a mystery.

We do know that blue jays are monogamous. In early spring, the male feeds the female as part of courtship. In many cases, the bond is lifelong, but some blue jays find a new partner after one or several breeding seasons.

Each pair has a home range, in which it nests and feeds. However, it does not defend this range against other blue jays, unless one threatens the nest. Pairs can have overlapping home ranges, and unmated jays may also share the space. Flocks of jays feed and hang out together, but membership is fluid, with individual jays joining in and leaving the group at any time of year.

Donald Kroodsma, in The Singing Life of Birds, reports observing many visits to a nest site by neighboring jays. The visitors and the nesting pair often vocalized during such encounters, but Kroodsma did not interpret the interactions as serious challenges from the nesting pair. Perhaps they’re just socializing.

Blue Jay Communication

You don’t hear blue jays singing in the dawn chorus of spring the way other passerines do. However, blue jays vocalize a lot, with an immense variety of sounds. No one has categorized them all, let alone figured out the context in which they all are used.

A typical sound is a loud, harsh jeer! or jay! (from which the bird may have gotten its name), often uttered when a jay feels threatened. I’ve seen other birds react to the jeer by vacating the premises. I’ve also watched other birds ignore it. Sometimes while vocalizing, blue jays bob their heads up and down, like demonstrators jiggling their signs to get the press to notice.

A blue jay reveals much about its mood and intentions by the crest posture. Relaxed, feeding with friends or getting a drink, a jay usually wears its crest sleeked to its head. In moments of excitement, the crest springs up. We can only speculate whether this is reflexive behavior or whether it can also be intentional communication.

When blue jays in a group make queedle queedle calls, sometimes they bob their heads at the same time. Human approach to a blue jay nest may elicit this call, too, but we don’t know exactly why. Blue jays also click, cluck, rattle, chortle, mew, whistle, peep, buzz, and ring like a bell.

Once in a while, a blue jay may perch in a tree and run through much of its vocal repertoire sotto voce, as if musing to itself, and this may be the closest a blue jay comes to singing. The function of this whispered song is not known.

Sometimes blue jays screech like red-shouldered hawks. Are they trying to trick other birds into abandoning food? Or is it like singing a song you learned on the radio? Jays can also sound like American kestrels, fish crows, eastern screech-owls, and domestic cats. Both females and males vocalize, and if there is a way to tell them apart by their sounds, we have not discovered it yet.

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Occasionally blue jays have been known to mimic human speech. Laura Erickson, a licensed wildlife rehabilitator, had firsthand experience with a blue jay’s mimicry. Erickson raised a brood of four blue jays whose nest had been destroyed, minimizing contact so they would not imprint on her, and released them when they were grown. Three took to the wild easily, but the fourth enjoyed people a little too much. After release, “Sneakers,” like Mary’s little lamb, followed some kids to school, played with them in the schoolyard, and, when recess was over, flew in through a classroom window, startling the teacher.

When a dog tried to attack Sneakers, and she showed no fear, it became clear that she could not survive as a wild bird. Erickson obtained a permit to keep her for use in educational programs. One day, Erickson’s husband heard his wife say, from the other room, “Here, come on.” However, Erickson was not at home. Sneakers had mimicked both the voice and sound of her guardian’s voice well enough to fool the person who knew Erickson best.

Helping Out

Erickson also had the opportunity to observe an act of blue jay altruism. Sneakers sneaked out of her cage one day when Erickson was gone and helped herself to the mealworms in a bucket. When Erickson returned, she found Sneakers loading up her throat pouch and taking the mealworms to another disabled jay that could not escape its cage.

Tool Making

Many members of the crow family have demonstrated tool use. Although there is no scientific evidence of wild blue jays using tools, a study (Jones and Kamil, 1973) showed that captive blue jays can use and make tools if motivated. The researchers put food pellets just out of reach from a hungry blue jay’s cage. The bird tore a strip of newspaper from the bottom of the cage, crumpled it with feet and bill, and used the paper to rake and sweep the food pellets into reach. On other occasions, the same bird used a feather, a thistle, a piece of straw grass, a paper clip, and a plastic bag tie to reach food. Five other jays in the captive colony subsequently learned to use tools to reach food. They learned from each other.

Why is a Blue Jay Blue?

The blue jay’s feathers include a palette of brilliant, shiny blues, from cobalt to turquoise. However, there is no blue pigment in its feathers, only black. The blue is a structural color. The barbs of the feather contain bubble-like nanostructures, visible only with an electron microscope. When light strikes the feather, the nanostructures filter out all color except blue. The remaining blue light reflects off a deeper layer of black pigment, which intensifies the blueness, and we see the jay’s vibrant blue colors. If you hold a blue jay feather up so that the light streams through it to your eye, rather than reflecting off it, the feather appears gray, with no trace of blue.

Maybe Not Hoodlums After All

James Audubon chose to paint blues jays robbing a nest, and he probably gave the species a bad rap for all time. In an 1897 study by F.E.L. Beal of 292 blue jay stomachs, only three contained eggshells. This exculpatory evidence notwithstanding, blue jays do rob nests—not to feed themselves, but only their babies, whose rapid growth requires large quantities of protein.

Blue jays are hardly the only birds that rob nests. Great-tailed, boat-tailed, and common grackles do it, too. Le Conte’s thrashers rob nests regularly. Other nest predators include roadrunners, caracaras, gulls, jaegers, and possibly even meadowlarks. And by the way, perhaps you had scrambled egg for breakfast this morning.

Blue Jay and Red-bellied Woodpecker

Territoriality and Aggression

Although blue jays are often accused of driving other birds from feeding stations, their boisterous arrival may allow the blue jay only a momentary advantage, rather than seriously barring other birds from the food. In my own backyard, a blue jay often bounces into the midst of birds at the feeders. Although many small birds will give way, they generally return quickly, often while the blue jay is still feeding.

Red-bellied woodpeckers, however, usually stand their ground. The blue jay in the photo on the right was bigger and heavier than the red-bellied woodpecker and occupied the higher position. However, when the woodpecker flared her tail and thrust her bill toward the blue jay, the jay abandoned its claim and exited in a hurry, stage left.

Migration and Other Movements

Blue jay movements remain something of an enigma. Banding studies show that the great majority stays in one general location year round. Some move from season to season or year to year but remain within a radius of only a few miles. Blue jays that breed in Florida seem not to migrate at all. In more northern states, as many as 20 percent do migrate significant distances, but an individual blue jay may migrate one year and not the next.

Flocks of blue jays flying purposefully are a common sight, especially in fall, and famously at the Great Lakes. We don’t know, though, exactly where they’re going and whether they’re relocating, heading to Florida, or simply heading off to cache nuts. Some of the jays at your feeders right now might not be the same ones you fed last summer, but they may have come from near or far and from any direction.

A blue jay can carry up to five acorns at once (three in the gular pouch, one in the mouth, and one in the bill tip), and they often fly as much as two miles to bury their treasure. They dig up many of the acorns and eat them later. However, they appear to forget the location of up to 70 percent of them.

Scientists infer that the rapid northern advance of oaks in the eastern United States after the last glacial period was due to the blue jay’s caching of acorns. I love to think of blue jays in this cosmic, long-view way. It’s pleasing to consider that a small bird can move a mighty forest. Every ecosystem has many moving parts. And even the smallest parts matter.

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