Why Are Snowy Owls White? Camouflage and Plumage Facts

White for camouflage in an open landscape

The Arctic tundra has no trees or tall bushes to hide behind. A large, dark bird sitting on open snow would be visible from far away to lemmings, hares, ptarmigan and ducks. A white owl on a snowy mound, by contrast, looks like part of the landscape. Birdwatchers often describe a resting snowy owl as looking like a lump of snow or a pale rock.

Camouflage helps in two ways. It lets the owl watch for prey without being noticed, and it makes the owl harder for its own enemies to spot. Adult snowy owls have few predators, but Arctic foxes, wolves, skuas and ravens raid nests, and a well-hidden female on her eggs is less likely to attract them.

Many Arctic animals share the same solution. Arctic foxes, Arctic hares, ptarmigan and polar bears are white or turn white in winter. Read about how one of them does it in Why do Arctic foxes change color?

Why are male snowy owls whiter than females?

Snowy owls are one of the clearest examples of an owl in which males and females look different. Adult males are nearly white, usually with a few small brown spots. Females are covered in dark brown bars on the back, wings and breast, with only the face and front of the neck plain white.

Scientists think the difference is linked to the roles of the two sexes:

• Females incubate the eggs and brood the chicks, sitting on the ground for weeks in early summer, when the tundra is a patchwork of melting snow, brown vegetation, lichen and rock. Dark barring breaks up the outline of the bird against this mottled background.
• Males hunt and guard the territory, often perched on a high point in plain view. Being very white may make them more conspicuous to rival males and to females, possibly signaling age and quality, while still blending with snow.

Even so, the difference is not absolute. A study of museum specimens in Russia found that only 3 of 129 adult males were almost completely without dark spots, and the darkest males and palest females can be hard to tell apart.

Young snowy owls are dark

Snowy owl chicks hatch covered in white down, which is soon replaced by a thick, dark gray-brown second down. This sooty color hides them well among the lichens, mosses and stones of the summer tundra, where they leave the nest at about three weeks old and hide among the hummocks before they can fly.

Young owls then grow barred feathers that look like an adult female’s, though usually darker. Young males are already a little less heavily marked than young females, and experts can often tell the sexes apart by the pattern of markings on the wings: bars in females, more spots in males.

Do snowy owls get whiter with age?

Yes. Snowy owls replace their feathers gradually over several years, and with each molt males in particular usually lose some of their dark markings. A male may take many years to reach its whitest plumage. Females also tend to become slightly paler with age but remain clearly barred.

This means a heavily marked snowy owl seen in winter could be a female of any age or a young male, while a nearly spotless bird is almost certainly an adult male.

How do white feathers keep snowy owls warm?

The color itself is mainly about camouflage, but the plumage is also a superb winter coat. Snowy owls have very dense feathers with a thick layer of fluffy down beneath them, trapping warm air next to the skin. Studies of heat loss suggest the snowy owl is one of the best-insulated birds in the world.

Feathers cover almost the whole body, including the legs and toes. The toe feathers average about 3 cm (1.2 in) long, the longest known for any owl, and they work like warm slippers on snow and ice. The bill is also largely hidden in feathers, which reduces heat loss from the face.

White feathers are white because they contain little or no pigment: their structure scatters all colors of light evenly. Feathers containing melanin are tougher and resist wear better, which is thought to be one reason many white birds, such as gulls and gannets, have dark wingtips. The same physics explains the pale coat of the polar bear, as described in Are polar bears really white?

Are snowy owls albino?

No. Albinism is a genetic condition in which an animal cannot make melanin, the dark pigment, so its eyes look pink or red and its skin is pale. Snowy owls have bright yellow eyes, black bills and claws, and dark markings in most of their feathers. Their white plumage is a normal feature of the species, shaped by natural selection for life in the far north.