About Snowy Owls
The Snowy Owl, the largest owl in North America by body mass, is equal parts graceful beauty and efficient predator.
Where Snowy Owls Live
During breeding season, which begins in May, Snowy Owls can be found on open tundra all the way around the Arctic Circle. In North America, some of the owls may stay on the breeding grounds through the rest of the year, weathering temperatures as low as -80°F. Others migrate as far south as the northern half of the lower 48 states states and during recent large irruptions have reached Bermuda, Cuba, and Hawaii. Snowy Owls are regular visitors to New England from around November through April.
Snowy Owls and Airports
As Snowy Owls migrate north and south, they look for stopping places that resemble their home, the Arctic tundra. To them, the land around Boston Logan International Airport fits the bill. It's low and flat, with short scruffy plants and grasses, and there’s an abundance of small mammals and birds to eat.
Logan Airport has the largest known concentration of Snowy Owls in the Northeast. The birds usually show up at the airport in early November; the earliest date recorded is October 22. They generally leave in early April; though in the winter of 2013-14 two owls stayed between Logan airport and the Boston Harbor Islands through the summer and fall and winter of the following year. This was the first time Snowy Owls were recorded in Massachusetts as resident owl species consistently for over a year.
The airport owls help by scaring away other birds that might endanger aircraft. Unfortunately, they are large enough to pose a threat themselves. To protect both birds and jets, Mass Audubon's Norman Smith safely captures and relocates snowy owls each year.
This work is performed with special permits. The public is not allowed to enter restricted airport property, or to capture any kind of owl or other raptor.
Physical Features of Snowy Owls
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Snowy Owls are the largest North American owls, and they’re among the largest owls in the world. They are 20”–28” in length, with a wing span of 54”–66”, and weigh 3.25–6.5 lbs. Males are typically smaller than females.
Despite their name, most Snowy Owls are not pure snowy white. They range from all white to black and white, with a pattern of dark, prominent bars—except on the face, which is always white. Females typically have more dark markings than males.
The eyes of Snowy Owls, like those of all owls, are enormous in proportion to their heads. Owls cannot move their eyes, so they must turn their entire heads, which they swivel a full 270° with the help of 14 neck vertebrae. Snowy owls have deep yellow eyes. A protruding upper eyelid acts as a shade from sunlight.
To keep the birds warm, the face, beak, legs, and feet of Snowy Owls are covered with fine, fur-like feathers. This heavy covering of feathers has made it difficult to read the owls' leg bands without recapturing them.
Listen to the sound of a Snowy Owl:
What Snowy Owls Eat
In the Arctic, Snowy Owls eat primarily lemmings. When they are here in winter they eat rodents, rabbits, other small mammals, many bird species especially waterfowl including geese, Great Blue Herons, gulls, and even other raptors including American Kestrels, Northern Harriers, and Short-eared Owls.
They swallow their food whole or in large chunks, and all the fur, feathers, and bones are compressed into a fur ball called a pellet, which they spit up daily. These pellets can be dissected to give an idea what the owls have been eating. However, field observations need to be done as well because when they capture a large prey item such as a duck they will pluck off the feathers and eat the breast, which may not show up in a pellet.
On their summer breeding grounds, it’s daylight 24 hours a day, so Snowy Owls hunt in the light. In the winter they prefer to find food under cover of darkness. They hunt by hovering in the air looking for prey, or by watching for prey from a perch.
The breeding population of Snowy Owls is declining, but the research is still being done to try to understand why. Most of the owls that are in Massachusetts during the winter are young, inexperienced, and face many challenges. They have to master the skill of hunting and evading predators; avoid being hit by vehicles or getting electrocuted; fend off disease and rodenticide poison; and deal with being disturbed by people while roosting and hunting.
As is true with other young raptors, many do not make it. It can be distressing to learn about an owl found dead or injured. It is important to remember that while some owls may not make it due to external threats, you can not judge the health of the entire wintering Snowy Owl population by the few that perish.
Smith’s research over the last 40-plus years has shown that many of the Snowy Owls that are captured and relocated are in great shape, and transmitters placed on them have proved that some do make it back to the Arctic, breed, and return in future years. One owl returned 23 years after it was banded and was healthy and in great body condition.
As a community of bird-lovers and conservationists, we can avoid making survival any more difficult for these spectacular raptors by giving them plenty of space!