Blue Jay Facts: 9 Things to Know, From Hawk Calls to Acorns
The blue jay is a loud, smart, crested bird found across the eastern and central United States and southern Canada. It is part of the crow family. It can copy the scream of a hawk, and it buries thousands of acorns each fall. Its feathers are not even truly blue. A blue jay is about 10 to 12 inches long and weighs about as much as two or three slices of bread. It eats mostly nuts, seeds, and bugs. It often mates for life and lives in tight family groups. The oldest wild blue jay on record lived to almost 27. Below are nine blue jay facts that explain why this common backyard bird is far more clever than it looks.
In this article
- Are blue jays really blue?
- Why do blue jays copy hawks?
- What sounds does a blue jay make?
- What does the crest tell you?
- How did blue jays help plant oak forests?
- What do blue jays eat?
- Do blue jays mate for life?
- Do blue jays migrate?
- How long do blue jays live?
- FAQ
Blue jay facts at a glance
| Fact | Blue jay |
|---|---|
| Science name | Cyanocitta cristata |
| Family | Crows, jays, and magpies |
| Length | About 10 to 12 inches |
| Weight | About 2.5 to 3.5 ounces |
| Wingspan | About 13 to 17 inches |
| Main foods | Acorns, nuts, seeds, grains, fruit, and bugs |
| Eggs per nest | 2 to 7 |
| Oldest known wild bird | At least 26 years, 11 months |
| Status | Low concern, but down about 27% since 1966 |
Source: Cornell Lab of Ornithology, All About Birds. Numbers are approximate.
1. Are blue jays really blue?
No, not in the way paint is blue. The color in a blue jay's feathers is melanin, and melanin is brown. The blue you see comes from light. Tiny parts on the surface of each feather bend and scatter light so that only blue bounces back to your eye. That is why the Cornell Lab of Ornithology says the blue comes from "scattering light." If you crush a blue jay feather, or hold it with light coming from behind it, the blue goes away and it looks dull brown or gray.
The black band across the face, neck, and throat is different on each bird. Scientists think it may help blue jays tell each other apart, a bit like a face.
2. Why do blue jays copy hawks?
Blue jays are great mimics, and their favorite thing to copy is a hawk. In the wild, they often copy the scream of the red-shouldered hawk and the red-tailed hawk. Scientists have two main ideas about why:
- A warning. The call may tell other jays that a real hawk is close by.
- A trick. A blue jay will sometimes give a hawk call as it flies up to a feeder. Other birds scatter, and the jay gets the food. Most of the birds come right back once they see it was just a jay.
Pet blue jays have even learned to copy human speech and the meow of a cat.
3. What sounds does a blue jay make?
Far more than one. The best-known call is a loud "jay! jay!" scream. But blue jays have a huge "vocabulary." They also make soft, quiet notes, a squeaky "pump-handle" call that sounds like a rusty gate, gurgles, clicks, and the hawk calls above. Some of the soft calls are only used between mates or family members.
Blue jays are not famous singers, but they do belong to the songbird group. If you want to know why birds sing at all, our guide on the science behind birdsong explains it in plain words.
4. What does the blue jay's crest tell you?
The crest is a mood ring you can read from across the yard. Blue jays talk with their bodies as well as their voices, and the crest is the main tool.
| Crest position | What it usually means |
|---|---|
| Flat, held down | Calm. Eating with family, sitting on eggs, or feeding chicks. |
| Partly raised | Alert, curious, or a little worked up. |
| Raised high | Excited or bold. A squawking jay almost always has its crest up. |
The rule is simple: the higher the crest, the more fired up the bird is.
A soft, easy tee for mornings at the feeder or a walk in the woods.
5. How did blue jays help plant oak forests?
Blue jays love acorns, and they are very good at saving them. A jay can carry up to five acorns at once: two or three in a pouch in its throat, one in its mouth, and one in the tip of its bill. In one study, six jays wearing small radio tags each hid 3,000 to 5,000 acorns in a single fall.
They don't eat them all. The ones they forget can sprout into new oak trees. Blue jays also tend to pick good acorns and skip ones with bugs inside. Scientists credit this habit with helping oak trees spread north after the last ice age. You can help too: Cornell suggests planting oak trees so future jays have acorns to eat.
6. What do blue jays eat?
Mostly plants, with some bugs. Across a year, about 22% of a blue jay's diet is insects. Nearly all the rest is acorns, nuts, fruit, seeds, and grains. They hold food in their feet and peck it open.
Blue jays have a bad name for robbing other birds' nests. They do it sometimes, but it is rare. In one large study of 530 blue jay stomachs, only 6 had any trace of eggs or baby birds. Blue jays are also less bossy at feeders than people think. In a Florida study, woodpeckers, grackles, and gray squirrels often pushed blue jays away from the food.
If you want blue jays at your feeder, Cornell says they like tray feeders or hopper feeders on a post, and they go for peanuts, sunflower seeds, and suet. They also drink from birdbaths.
7. Do blue jays mate for life?
Often, yes. Blue jay pairs usually stay together all year, and many stay together for life. They split the work. Both build the nest, but the male gathers more of the twigs and the female does more of the building. Only the female sits on the eggs. While she does, her mate brings her all of her food.
A nest holds 2 to 7 eggs. The eggs hatch in about 17 to 18 days, and the chicks leave the nest about 17 to 21 days later. The parents keep feeding the young for one to two more months.
Here is a tip worth knowing: a day or so before they leave the nest, some chicks hop up to 15 feet away and beg loudly. This is when many people find what looks like an "abandoned" baby jay. In most cases the parents are close by. If you can, place the chick back in or near the nest, and the parents will go on feeding it.
8. Do blue jays migrate?
Some do, and nobody fully knows why. Blue jays are the only jays in the Americas that migrate north and south. Thousands fly in loose flocks along the Great Lakes and the Atlantic coast each fall. Yet many stay put all winter, and Cornell estimates that probably fewer than 20% of blue jays migrate at all.
It gets stranger. The same bird may fly south one year, stay north the next, and fly south again the year after. Young and adult jays both do it. Scientists still have not worked out the pattern. For a deeper look at why birds make long trips at all, see our post on the real reasons birds migrate.
9. How long do blue jays live?
Most wild birds live far shorter lives than their record holders, but blue jays can last a long time. The oldest known wild blue jay was at least 26 years and 11 months old. It was banded in Newfoundland and Labrador in 1989 and found again in 2016.
Blue jays are still common, with about 17 million breeding birds, according to Partners in Flight. But their numbers fell by about 27% from 1966 to 2019, based on the North American Breeding Bird Survey. Cornell notes that the most common human-linked cause of death for blue jays is attacks by pet cats and dogs. Keeping cats indoors is one of the simplest ways to help backyard birds.
Frequently asked questions
Are blue jays aggressive?
They are loud and bold, so they seem tough. But studies show they are less pushy than many other birds. Woodpeckers, grackles, and squirrels often chase them off feeders.
Are blue jays smart?
Yes. They belong to the same family as crows and ravens. They remember where they hid thousands of acorns, copy other animals' calls, and live in close family groups. Captive blue jays have even used strips of newspaper to pull food pellets into their cages.
What does it mean when a blue jay copies a hawk?
It may be a warning that a real hawk is near. It may also be a trick to scare other birds off a feeder so the jay can eat first.
Is the blue jay a state bird?
No U.S. state has picked the blue jay as its state bird. It is the official bird of Prince Edward Island in Canada, chosen by a public vote in the 1970s.
What is the difference between a blue jay and a Steller's jay?
Blue jays live mostly east of the Rocky Mountains and have a white belly and a black face band. Steller's jays live in the West, have a dark, sooty head and crest, and lack the white belly.
Do blue jays stay all winter?
Many do. Most blue jays stay in the same area all year, and you can often see them at winter feeders.
For the bird lover in your life (or you)
Tees, crewnecks, and more for people who know every jay at the feeder by its face.
A warm, cozy crewneck for chilly mornings watching jays bury acorns.
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