Meet the blue jay, the intelligent rascal of the bird world
When it comes to blue jays, there seem to be two schools of thought. One group thinks they are bullies that intimidate other birds, blah, blah, blah. Obviously, I don't subscribe to that school. Others of us enjoy the dash of colorful antics blue jays add to our winter bird feeding stations.
Speaking of which, I grew up with a bird feeder immediately outside my bedroom window. Chickadees, juncos, and nuthatches were cute and all but when a blue jay appeared, you knew the big game had arrived! It came in with a long tail, an impressive crest on its head, and an unmistakable attitude that said, "Look out world, the jay is here!"
As the years pass and I continue to watch and listen to blue jays, I am convinced they are so smart that they find everyday life to be something of a bore. So, they invent ways to liven things up to entertain themselves. Before getting to the entertainment, let's review their place in nature.
Color and habitat
To start off, there are no blue pigments in blue jay plumage. Instead, the feathers have a thin layer of cells that absorb all wavelengths of color except blue. When illuminated, their blue color intensifies. Out of the sunlight, the blue tone dims.
Of course, they are actually black-and-white and blue jays. Their wings and tail are boldly marked with black bars and white tips. Underneath, they are grayish white with black. Their distinctive crest is blue in front and black in back. The sides of their heads are white with a black line going through the eyes. Both genders have the same coloration.
The species can be found in deciduous, coniferous, and mixed forests. They are common in towns and residential areas. Here in Illinois, blue jays are more likely to be seen in communities than in nearby mature forests.
What they eat
When it comes to their diet, suffice to say that the jay puts the "omni-" in omnivorous. We'll start with the animal side of omnivore. Jays eat ground beetles, caterpillars, click beetles, wireworms, wasps, spiders, millipedes, and snails.
What about bird eggs and nestlings? In one study of 530 jay stomachs, only six contained eggs or nestling remains. That's around 1%. Extensive research supports this 1% figure.
On the flip side, predation is responsible for most blue jay nest failures.
Predators that eat young jays include broad-winged hawk, Cooper's hawk, red-tailed hawk, peregrine falcon, great horned owls, and screech owls. So how about some sympathy for the jays?
Now, back to the vegetative side of the jays' diet. This brings us to mast. No, blue jays aren't sailors. In this case, mast refers to the nut-fruits of forest trees and shrubs. In particular, we are talking about beechnuts, chestnuts, hazelnuts, hickory nuts and acorns. Since these nuts are hard, they don't rot quickly and are available to blue jays all year. In fact, they make up 43% of the blue jays' diet. You can understand why blue jays are fond of sunflower seeds or peanuts (unsalted) at a feeder.
Another reason why mast is available all year is because blue jays will store or cache nuts for future retrieval. Keep in mind that one blue jay was seen packing around 100 sunflower seeds in its gullet. So it should come as no surprise that one study of 50 jays found that, on average, a jay could select and hide roughly 107 acorns per day.
Some of you may be thinking of squirrels that store acorns for later use. Be they birds or mammals, these animals don't always recall where they stored the nuts or live long enough to recover them. As you might expect, some of these forgotten kernels sprout into trees. This is all well and good. If the acorns didn't hitch a ride, they'd all be competing with the parent tree for food, sunlight, and water.
Of course, a jay can take a nut a lot farther than a squirrel. Blue jays will bury seeds up to two miles from their parent tree. In fact, eleven species of oaks depend on jays for dispersal of their acorns. Some biologists believe that thousands of years ago jays helped spread oak trees north as the glaciers receded.
The sounds they make
So much for what goes down a jay's beak. Time to talk about the sounds that come out of a blue jay's beak. As a writer, I like to think that a healthy vocabulary is a sign of intelligence. If that's the case, then a blue jay is definitely not a bird brain.
Consider the following from a scientific life history of the blue jay:
"Because of extensive gradation of sounds, the ability to produce two different sounds simultaneously via the syrinx [a bird's voice organ], and mimicry of environmental sounds, the total vocabulary of a blue jay is immense ..."
The categories of vocalizations blue jays make come with some surprisingly descriptive terms: jeer calls, rattle calls, pumphandle calls, swallowing calls, peep call, whisper song, squawk call and contact calls. These categories are anything but precise.
Don't worry, we won't be going through them all.
I do want to talk about the jeer call. This is a loud nonmusical call that is used when potentially threatened by a human or predator. Interestingly, other birds respond to the jay's alarm call. They know that means to look out for trouble. The blue jay is something of a neighborhood sentinel in this regard. The jeer call is also used in other circumstances but let's move on to mimicry.
The curious thing is that while jays warn of approaching birds of prey, they also mimic them. They will mimic red-shouldered hawk, red-tailed hawk, broad-winged hawk, Cooper's hawk, American kestrel, and the eastern screech owl. Why?
A few possible explanations have been offered. Two hypotheses assert that the jay is advising that either a hawk was or is here. The "idiot mimic" hypothesis argues that they make these sounds simply because they have heard them before. The "deceptive hypothesis" says the jays are trying to fool other species into thinking a hawk is close by.
Which one do I subscribe to? All of the above. Experiments done in captivity indicate that juvenile blue jays learn the calls of their nest mates perhaps while still in the nest. If such auditory acuity is the case, why limit the answer to only one hypothesis? Maybe one bird is just mimicking a familiar call or telling another jay about the annoying raptor that flew by earlier in the day. You know, a clever jay has to do something for entertainment.
Better yet, two blue jays fly near a feeding station and see that it's crowded with possible competitors. One of the jays gives out a raptor call and they watch all the other birds head for the brush while they alight and enjoy their choice of sunflower seeds and peanuts. I don't doubt for one second that these intelligent rascals would be capable of such a strategy. One of the other sounds a blue jay makes is a chortle, which I would expect to hear at this feeder!
• Mark Spreyer is executive director of the Stillman Nature Center in Barrington. Email him at email@example.com.