Black-billed magpie

A black-billed magpie in frosty branches, showing its black-and-white body and long tail.Tom Koerner / USFWS Mountain-Prairie
A black-billed magpie perched among green leaves.Becky Matsubara

Black-billed magpie at a glance

Pica hudsonia MAG-pie; Pica hudsonia is PY-kuh hud-SOH-nee-uh

Type: Bird · corvid
Diet: Omnivore
Size: About 17 to 22 inches long (43 to 56 cm), roughly the length of a skateboard, but half of that is tail. It weighs about as much as a stick of butter (5 to 7.5 ounces / 145 to 210 g).
Lifespan: Typically 3 to 7 years in the wild; the oldest banded black-billed magpie on record lived at least 9 years and 5 months.
Conservation: Least concern

Eats insects, carrion, grain, seeds, ticks off elk and deer, other birds' eggs

A magpie probes the ground for insects and worms, catches flying insects, robs other birds' nests, and eats roadkill and other carrion. It also lands directly on elk and deer to pick ticks from their fur.

Should you worry?

None to worry about. A nesting pair will scold and dive at anything near the nest, including people, but they do not attack. Give a nest tree room and leave it alone.

At a pullout in Theodore Roosevelt, an elk stands still in the grass while a black-and-white bird walks up its flank and starts working through the fur near its ear. The elk doesn’t flinch. The magpie isn’t grooming out of kindness — it’s after ticks, and this particular elk has apparently decided the bird can stay.

Not every elk makes that call, and not every magpie tries the landing. A 2017 study of black-billed magpies and elk in western Canada found the whole arrangement runs on personality: bold magpies are willing to risk a landing on a large animal, timid ones almost never attempt it, and bold elk shrug the birds off while shy elk hold still and let them work. Most of what a magpie plucks off isn’t even eaten on the spot — the bird tucks a share of the ticks away alive, the same habit of hoarding that shows up across the whole crow family. Watch a herd near a pullout long enough and you can start to guess, correctly or not, which animals will let the bird land and which won’t.

A magpie can afford the confidence. Its tail alone runs half its body length, and a nesting pair will dive at anything that gets too close to their domed stick nest — coyotes, bears, people, animals many times their size. The same boldness that lets one bird pick ticks off an elk’s back is what makes the species impossible to overlook at a Yellowstone or Theodore Roosevelt pullout: something that size, moving that sure of itself, tends to get noticed.

Did you know?

A black-billed magpie's tail makes up about half its total length — cut the tail off and the bird would be barely bigger than a robin.
Magpies nest and travel in loose colonies, and a pair defending eggs will dive at animals many times their size, including bears and elk.
The oldest black-billed magpie on record, recaptured during banding in Saskatchewan, had reached at least 9 years and 5 months.

Common questions

Are black-billed magpies dangerous to kids?

No. They scold and dive at intruders near a nest, but they don't attack people. Keep your distance from a nest tree and they'll settle down.

Why do you see magpies riding on elk and deer?

They're picking off ticks. Not every magpie tries it and not every elk allows it — a 2017 study found bold magpies land on shy elk, while bold elk shake the birds off.

What do black-billed magpies eat?

Almost anything: insects, worms, grain, roadkill, other birds' eggs, and ticks pulled straight off a deer or elk.

How can you tell a magpie from a crow?

The tail. A magpie's tail is as long as the rest of its body, and its wings flash white and iridescent green in flight — a crow is all black with a short tail.

What eats a black-billed magpie?

Hawks, great horned owls, and ravens catch young birds just out of the nest. Crows, raccoons, weasels, and even red squirrels eat eggs and nestlings. The domed roof a magpie builds over its nest may help keep owls and ravens out.