The Snowy Owl, the largest owl in North America by body mass, is equal parts graceful beauty and efficient predator. "Snowies" typically arrive in Massachusetts around November and then head back north to their Arctic breeding ground in April.
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 and during recent large irruptions have reached Bermuda, Cuba, and Hawaii. Snowy Owls are regular visitors to New England from around November through April.
Physical Features of Snowy Owls
Snowy Owls 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
Courtesy of the Macaulay Library.
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.
Threats to Snowy Owls
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 cannot judge the health of the entire wintering Snowy Owl population by the few that perish.
Snowy Owls in Massachusetts
Snowy Owls arriving in Massachusetts tend to seek local habitats that mimic the Arctic tundra where they spend most of their lives such as large salt marshes, extensive agricultural fields, and even airports. Popular sighting areas include Westport, New Bedford, Nantucket, Orleans, Duxbury Beach, Salisbury State Park, and Plum Island.
The number of Snowies that appear each season varies from year to year. They are considered an irruptive species—one that responds to changes in the conditions of its home territory by moving elsewhere in search of food. Some of the factors that may trigger these irruptions include variations in food supply in the Arctic, severe snow and ice cover in their usual wintering areas, or a superabundance of owls resulting from an exceptional nesting season prior to a southward irruption.
How Mass Audubon is Helping Snowy Owls
Mass Audubon is working to protect Snowy Owls, which are the largest owls in North America. Norman Smith, former director of Mass Audubon's Blue Hills Trailside Museum, has been studying them since 1981. As part of his research, he attaches bands and transmitters to Snowy Owls at Boston Logan International Airport, and then tracks their travels.
Please Note: 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.
How You Can Help Snowy Owls
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!
Safely Viewing Snowy Owls
When Snowy Owls are in Massachusetts, they are primarily nocturnal like other owl species and mostly roost during the daytime to conserve energy.
Groups of observers can keep Snowy Owls from resting, and some birds are forced to fly and relocate repeatedly if multiple photographers or birders approach them. Protecting birds means giving them the space they need while roosting and hunting so they can hopefully make it back to the Arctic to breed, giving future generations of wildlife watchers the opportunity to enjoy these magnificent creatures as well.
→ When observing an owl from the road, from a frequently traveled path, or a beach, try to stay at least 50 yards (150 feet) away. That’s about half of a football field, or five school buses stacked end-to-end.
→ When viewing an owl with a group of people, view from one location and never surround or attempt to approach the owl to get a better view or photograph.
→ Always watch the Snowy Owl’s behavior: if the bird becomes alert, extends its neck upright, and eyes become wide open, you have disturbed it from its roosting mode and you should back off immediately.
Support the Snowy Owl Project
You can help Mass Audubon keep Snowy Owls safe and track their movements.