Snowy owls are once again popping up all over Maine — atop Cadillac Mountain, in Bangor-area fields and near the State Capitol Building. Migrating down from the Arctic tundra, many of these majestic birds will likely remain in Maine throughout the winter, and biologists believe more owls may be on their way.
Last winter, snowy owls migrated to the United States in unprecedented numbers, a phenomenon known as an “irruption.”
“It could be another good winter this year as well,” said Norman Smith, leader of the Snowy Owl Project. The Director of Mass Audubon’s Blue Hills Trailside Museum, Smith has been studying snowy owls since 1981, and he’s been tracking their migrations with leg bands and transmitters since 1997.
“They’re a little earlier this year than usual,” said Smith, who began seeing snowy owls in Massachusetts about two weeks ago. “They usually show up around the second or third week of November.”
Each winter, some snowy owls stay at their breeding grounds in the Arctic, while other snowy owls migrate south.
“They’re always in Maine, usually in low numbers and usually in the winter,” said Maine raptor specialist Erynn Call, biologist at the Maine Department of Inland Fisheries and Wildlife.
The number of snowy owls that migrate to Maine and the rest of the U.S. fluctuate greatly from year to year. This trend can be viewed on ebird, where people report bird sightings across the globe.
“The lemming population is what really stimulates the whole thing,” said Smith.
The lemming, a rodent that’s abundant in the Arctic tundra, is the snowy owl’s main food source during breeding season. Generally, the more lemmings there are, the more snowy owls chicks hatch and survive.
“The owls are capable of producing up to nine eggs when food is plentiful,” Call said.
If the snowy owl population grows, more of the owls are forced to fly south in the winter in search of food.
Biologists believe that’s what happened in winter of 2013-14, when the U.S. saw the biggest invasion snowy owls in decades.
It’s impossible to know the exact number of snowy owls that came to Maine that winter, but the spike numbers is evident on eBird, where in just one week in December, people reported 3,823 sightings of snowy owls in Maine. In comparison, in 2012, only 625 Maine snowy owl sightings were recorded for that week.
“This past year, there were some reports of snowy owls even in July in Ogunquit and York,” Call said. “Those could be younger birds not interested in breeding, so they didn’t need to go back to the Arctic to breed.”
Typically, snowy owls don’t breed until they’re at least 2 year old, Call said.
“There’s no way of predicting how many will come this year,” Smith said. However, he said that snowy owls had “an incredible breeding year” this year in central Canada, which makes him hopeful that snowy owl numbers will be high in the U.S. this winter.
In Maine, where lemmings are scarce, snowy owls pursue a variety of prey, from mice to hawks.
“They’re incredibly fast-flying birds, and they’re very agile,” said Smith. “They catch a variety of small mammals and birds. I’ve seen them catch other raptors … I’ve even photographed one taking a peregrine falcon.”
Snowy owls are fairy easy to spot, to the delight of wildlife enthusiasts. Unlike many other owls, “snowies” prefer open spaces, such as fields, because it resembles the tundra, Smith said. And while hunting the open spaces, they often perch in a tree or some other elevated object. In Maine, they’re often seen on fence posts, telephone poles and even rooftops.
Another reason these owls are easy to spot is because they’re snowy white (with individualized black banding), meaning they don’t blend in particularly well unless sitting in the snow. Also, while snowy owls typically hunt at night, they’ll also hunt during the day. After all, in the Arctic, they live in perpetual daylight during the summer.
“I think it’s a great opportunity for viewing wildlife,” Call said. “The most important thing is to maintain a good distance away and use your binoculars, even if you are able to get close.”
“If the bird starts to get erect and nervous and is moving around, that means you’ve gotten too close and should back off,” Smith said. “These birds are primarily nocturnal hunters, and during the daytime is usually when they roost and get their rest.”
Another thing to consider when viewing a snowy owl is whether you’re disturbing its prey — small mammals and other birds, Call said. It’s important not to interfere with their hunting success.
“The majority of the birds that come down are young birds that are inexperienced,” said Smith.
You’ll notice that most of these snowy owls are not completely white. They have a variety of dark banding, especially on their body, and each owl has a different pattern.
Usually snowy owls get whiter as they age, Smith said, but that’s not always the case. He’s seen the opposite occur — an owl become darker, with more banded feathers, as it ages. An individual owl’s patterning changes year to year.
“That’s why we band birds,” Smith said. It’s the best way of keeping track of individual owls.
In 2013, a number of owl researchers, including Smith, established Project SNOWstorm, a research program to gather information about snowy owls through telemetry, banding, toxicology screening, DNA analysis and more.
“They’re certainly a beautiful creature,” Smith said. “I think it’s a special experience to get to see these birds and see them adapt to new places. People should cherish this opportunity.”
Learn about Project SNOWstorm and contribute owl photos at www.projectsnowstorm.org, and learn about Smith’s Snowy Owl Project at www.massaudubon.org/get-outdoors/wildlife-sanctuaries/blue-hills-trailside-museum/snowy-owl-project.