By Loren Merrill
From our January 2024 issue
An aura of mystery surrounds the comings and goings of snowy owls in Maine. The first birds show up between October and December in areas reminiscent of their summer hunting grounds on the Arctic tundra: frozen salt marshes, sand dunes, rocky headlands, blueberry barrens, mountaintops, even airport runways. They may stay for a few months or disappear within days. Some winters, only a handful of owls are seen; in others, hundreds appear. Wherever they’re spotted, a swarm of people carrying binoculars and cameras is likely to follow. Until recently, that was perhaps the most predictable feature of the elusive white birds’ presence.
Now, a more detailed picture of the lives of snowy owls is emerging from Project SNOWstorm, a nonprofit and mostly volunteer-run research organization that has tracked the movements of more than 100 snowies in Maine and 16 other states and Canadian provinces over the past decade. Every bird caught in a baited trap is outfitted with a harness carrying a lightweight, solar-powered transmitter that records its precise location — latitude, longitude, and altitude — as often as every 30 seconds. Whenever the owl passes within range of a cell tower, the data uploads to Project SNOWstorm’s network. “We’re trying to understand how snowy owls use the landscape when they come south,” cofounder Scott Weidensaul says.
In Maine, Project SNOWstorm works with the USDA’s Wildlife Services program, which has captured four snowies since 2016, and the Portland-based Biodiversity Research Institute, which tags and releases the birds. The owls, named York, Wells, Brunswick, and Casco, after the towns where they were captured or released, have been living dissimilar lives, the data reveals. For example, Brunswick, a female caught at Brunswick Executive Airport in 2016, was relocated to the Rachel Carson National Wildlife Refuge in Wells, where she remained for much of the winter. By contrast, Casco, another female, was moved from the Portland International Jetport to a Washington County blueberry barren and almost immediately flew a few hundred miles north through New Brunswick and Quebec before looping back to the coast near Portsmouth, New Hampshire.
The owls’ differing behaviors may be driven by food sources. In the Arctic, snowies eat mostly lemmings and voles. Here, they’re bon vivants: They still consume lots of voles and other small mammals, but also ducks, grebes, gulls, and even loons. They’re strong fliers, capable of extended flights over water (one appeared in Hawaii in 2011), and will pluck birds from the ocean surface, often under cover of darkness. Personality may also impact the owls’ movements. “I frankly put a lot of it down to individualism,” Weidensaul says. “Each owl is its own self, and some have itchy feet.”
Project SNOWstorm’s researchers hope to put transmitters on three new birds in Acadia National Park this winter. Snowies have resided around Cadillac and Sargent mountains for many winters, but little is known about where they forage and how interactions with humans might affect them. “We and the National Park Service are interested in how snowy owls use these alpine environments, to what extent hikers and other visitors may be disturbing them, and whether people and owls can coexist easily on the mountaintops,” Weidensaul says.
Human impact is a significant focus of the project’s work. Southern Maine’s coastal salt marshes provide some of the state’s best snowy habitat, but the wetlands often abut housing developments, providing easy access for owl watchers, who frequently post sightings online. Most keep a quiet, respectful distance, but enough have harassed owls in pursuit of photos that two Facebook groups, Maine Birds and Maine Wildlife, no longer allow snowy pictures.
Vehicle strikes and loss of wintering habitat due to development and climate change are also major threats to snowies, which the U.S. Fish and Wildlife Service has labeled Birds of Conservation Concern. Tracking their movements, Weidensaul says, “helps us better understand the threats they face and how we can better safeguard them in a rapidly changing world.”
