Bird Profile

Blue Jay

Blue Jays are the loudest, smartest and most divisive birds at a North American feeder. Fed the right food in the right place, they stop being a problem and start being the best show in the yard.

The Blue Jay (Cyanocitta cristata) is a crested, robin-plus-sized corvid of oak woods, suburbs and city parks east of the Rockies, about 10 to 12 inches (25 to 30 cm) long with a bright blue back, a black necklace across a white face and throat, and black and white barring in the wings and tail.

It is the bird most likely to be described as a nuisance and the one most likely to be missed if it leaves. Jays are noisy, dominant at the tray and capable of emptying a feeder fast. They also plant oak trees by the thousand, spot every hawk within a quarter mile, and remember exactly where your peanuts are.

This profile covers identification against the other North American jays, what jays actually eat, the feeder arrangement that keeps them from monopolizing everything, their caching and mimicry behavior, nesting, and how their populations are holding up.

How to identify a Blue Jay#

Blue on the back, wings and tail. White or pale gray below. A pointed blue crest that goes up when the bird is agitated and flat when it is relaxed. A black line runs from the bill through the eye and around the throat as a necklace, and the wings and tail are barred with black and marked with white patches that flash in flight.

Males and females look identical. Juveniles are duller and shorter-crested but recognizable from the moment they leave the nest.

The blue is structural, not pigment. There is no blue pigment in the feathers; the color comes from light scattering in the feather microstructure, which is why a Blue Jay feather looks brown-gray when you hold it up with light shining through it.

The flight is the other clue: a steady, level, unhurried flap-flap-flap across an opening, quite unlike the bounding flight of most yard birds.

Where and when you will see Blue Jays#

Blue Jays occupy the eastern two thirds of the continent, from southern Canada to the Gulf, west to roughly the Great Plains. Their range has been creeping northwest for decades, and they now overlap and occasionally hybridize with Steller's Jay in the Front Range foothills of Colorado.

They are strongly associated with oaks. If your neighborhood has mature oaks, beeches or hickories, you have jays, and their numbers will swing with the acorn crop from year to year.

Feeder activity peaks in fall, when caching drives them to move as much food as they can carry. Late summer is the quietest period, when adults are molting and nesting birds are keeping their heads down. Winter brings them back in small family groups.

What Blue Jays eat and how they carry it#

Roughly three quarters of a jay's annual diet is plant material, dominated by acorns and other nuts, plus seeds, waste grain and fruit. The rest is animal food: caterpillars, beetles, grasshoppers and cicadas in summer, with occasional eggs, nestlings, small vertebrates and carrion.

The remarkable part is the transport. A Blue Jay can hold several acorns at once in its expandable throat and esophagus plus one in the bill, fly up to a mile or more, and bury them individually in soil or leaf litter. A single jay may cache thousands of nuts in a fall. Many are never retrieved, and jays are considered a major reason oaks were able to spread north as quickly as they did after the last glaciation.

At the feeder that instinct is why a jay grabs, leaves and returns 30 seconds later. It is not eating the seed. It is moving it.

The feeder setup for jays#

Blue Jays weigh around 3 oz (85 g), heavy enough to trip a weight-activated feeder and too big for most tube perches, which is the whole basis of managing them.

• To feed jays: an open platform or tray feeder or a peanut feeder with a wide mesh that takes whole nuts.
• To exclude jays: a caged feeder with mesh openings around 1.5 inches (4 cm), or a tube with short perches and no tray. Switching the main feeder to safflower seed does most of the rest.
• For suet: an upside-down or tail-prop suet feeder lets woodpeckers feed while making it awkward for jays.

Keep the jay tray separate and at a distance. Feeders too close together let one dominant species control all of them at once, a spacing problem covered in how many feeders and how far apart.

Behavior worth knowing#

Mimicry. Blue Jays imitate Red-shouldered and Red-tailed Hawks well enough to fool people and, apparently, other birds. Whether a given scream is a genuine alarm, a probe to see if a hawk responds, or a trick to clear a feeder is debated, and all three probably happen.

Mobbing. Jays gather and harass hawks, owls and cats loudly and persistently. If your yard erupts, look for the predator, since jays find them long before you do. This is the same instinct that makes them useful early warning for hawks hunting at your feeder.

Memory. Jays cache food in thousands of separate spots and recover a good share of it months later. They also learn feeder routines fast: a jay that has seen you fill a tray twice will be waiting the third time.

Anting. Jays sometimes crush ants and rub them through their feathers, or sit on an ant nest with wings spread. The purpose is uncertain, with feather maintenance and parasite control both proposed.

Nesting#

Pairs build a bulky cup nest of twigs, bark, moss, grass and sometimes mud, generally 10 to 25 feet (3 to 8 m) up in the crotch or outer branches of a tree, often a conifer. Both sexes build, and jays will snap fresh twigs off living trees rather than pick up dead ones.

Clutches are usually 3 to 6 pale blue to greenish eggs with brown spotting. The female incubates for 17 to 18 days while the male feeds her, and the young fledge at 17 to 21 days. One brood a year is typical.

Nesting jays go conspicuously quiet. A pair that shrieked all winter can raise a family 40 feet from your kitchen window without you noticing.

Population and conservation#

Blue Jays are common and widespread, though continental surveys have shown a slow long-term decline in parts of their range. They remain in no danger, and their range is still expanding northwest.

The one event that visibly dented them was West Nile virus, which arrived in North America in 1999. Corvids are unusually susceptible, and jay and crow numbers dropped sharply in affected regions in the early 2000s before recovering in most areas.

At a feeder, the practical risks are the same as for any bird that gathers in groups: contaminated seed and dirty surfaces. Jays feed on open trays, which are the hardest feeders to keep clean, so scrub and dry the tray weekly using the method in how to clean a bird feeder and never let wet seed sit on it.

Living with Blue Jays#

• Feed them deliberately on a separate tray with whole peanuts, and they will bother the tube feeder less.
• Use safflower in the main feeder if you want cardinals and finches to have priority.
• Space feeders widely so a jay flock cannot hold all of them at once.
• Watch the alarm calls. A screaming jay usually means a hawk, an owl or a cat.
• Expect gaps. Quiet Julys and busy Octobers are normal jay behavior, not a fault in your setup.