Snowy Owl after release. (All photographs © Raymond MacDonald)
The winter of 2013–2014 was an incredible year for seeing Snowy Owls in both eastern Canada and the eastern United States. Snowy Owls were recorded as far south as Bermuda, Florida, and Louisiana. It was by far the best winter for Snowy Owls that I have observed in Massachusetts since 1981 when I started my research on wintering Snowy Owls at Logan International Airport in Boston.
To put last winter in perspective, the greatest number of Snowy Owls I had captured and banded at Logan Airport previously in one winter was 43 in the winter of 1986–87, and the total banded in the Greater Boston area was 53 in the winter of 2011–12. During the winter of 2013–14, I banded 120 Snowy Owls at Logan Airport alone. I banded a total of 176 new owls and captured three owls that I had banded in previous years for a total of 179 Snowy Owls captured in the Greater Boston area. Most of those owls—96%—were hatch year owls in good condition. They were seen throughout the Commonwealth of Massachusetts from the first sighting in a backyard in Dorchester to the top of Mount Greylock and everywhere in between: downtown Boston, parks, refuges, beaches, cities, suburbs, and rural areas.
The magnitude of the influx of Snowy Owls into the eastern United States and Canada was partially reflected in Christmas Bird Count data. For instance, the Nantucket count recorded 33 Snowy Owls in the 2013–4 tally, against a previous high of four. The Greater Boston count, which includes Logan International Airport, tallied 28, compared to the previous high of 21. Statewide, 167 Snowy Owls were counted in 19 of the 34 Massachusetts count circles, beating the current record of 46 owls in 1949–50. Of course, there were far fewer bird counters and count circles in earlier days, so the number of Snowy Owls per party hour last winter (0.0507) is a tenth of the number (0.4894) for the 1949–50 count.
I banded my first Snowy Owl in Massachusetts in 1977 in Squantum and have been fascinated with them ever since. In 1981, I started a project at Logan Airport to observe, band, and relocate Snowy Owls. I have spent countless days and nights in every imaginable weather condition each winter observing owls roosting, hunting, interacting with other Snowy Owls as well as with other raptors, collecting pellets, trapping, banding, color-marking, and relocating Snowy Owls. We have 33 years of consistent data.
Snowy Owl with satellite transmitter.
In 2000, we were the first researchers to attach satellite transmitters on wintering Snowy Owls to track them, and proved for the first time that some of our wintering owls do make it back to the Arctic and return here in subsequent years. We have had 22 Snowy Owls return to Logan Airport from 2 to 16 years after they were banded. Some owls have gotten whiter with age, some darker with age, and some have not changed. We use the owls’ weights, wing and tail lengths, and signs of molt in order to age and sex the birds. It can be difficult to correctly age and sex a perched Snowy Owl.
Satellite transmitters enable us to learn more about the owls’ seasonal movements. For example, in February 2012, we put a satellite PTT (platform transmitter terminal) on a Snowy Owl from Logan Airport and released it at Plum Island. The owl spent the summer in Nunavut, Canada west of Baffin Island. On November 24, 2012, that owl returned to Logan Airport, having traveled more than 7,000 miles in 10 months.
Birds, especially flocking birds, are not welcome at airports for good reason. In 1960, starlings were sucked into the engines of Eastern Airlines flight 375, causing it to crash into Boston Harbor killing 62 people. Snowy Owls are not a high-risk species at airports because they do not fly in flocks; however, they can and have caused damage to aircraft at several airports. From 1990 through 2012, at least 73 Snowy Owls have been struck and killed across the country—more than have been documented dying from starvation—according to information presented by Richard A. Dolbeer, Science Advisor, Airport Wildlife Hazards Program USDA APHIS Wildlife Services, at the 2014 International Airport Winter Operations Conference on July 29, 2014, at Logan Airport. For the safety of the planes and the birds, we trap and relocate as many Snowy Owls as we can each winter.
Norman Smith and his assistants Carmella and Alexa releasing an owl.
On the wintering grounds at Logan Airport, Snowy Owls generally show up in early November. The earliest arrival record is October 22. The owls usually stay until sometime in April, occasionally in May, or rarely in June. The latest Massachusetts departure record of July 7 was broken the summer of 2014 when two Snowy Owls spent the summer and fall on the airfield at Logan Airport and the Boston Harbor Islands.
Snowy Owls on the summer breeding grounds are diurnal because it never gets dark. Using night vision equipment, we have found that in winter Snowy Owls do most of their hunting at night in Massachusetts. We have collected, dissected, and analyzed more than 6,500 pellets to determine what they eat. In addition, we have watched them capture an assortment of mammals including rodents, rabbits, and cats; birds including passerines, ducks, geese, Great Blue Herons, and gulls; and other raptors such as Northern Harriers, Peregrine Falcons, American Kestrels, Short-eared Owls, Long- Eared Owls, Barn owls, Saw-whet Owls, Barred Owls, and even another Snowy Owl.
Historic speculation on Snowy Owls suggests that they move from the Arctic in search of food, become emaciated, and die without returning to the Arctic. We have captured, weighed, and examined live owls in winter and our research shows that, to the contrary, when owls are abundant in winter they are mostly young owls in good condition. Tom McDonald, from Rochester, New York, has been banding Snowy Owls for 25 years with the same results. The owls are not emaciated and dying of starvation as many believed.
Snowy Owls breed only when adequate lemmings are available (Denver Holt, personal communication). An abundant food supply on the breeding grounds in 2013 resulted in a large number of young hatched. With the record numbers of young owls showing up in eastern Canada and the United States during the winter of 2013–2014, there had to be lemmings somewhere in the Arctic. In the summer of 2013, Northern Quebec had an incredibly abundant lemming population, resulting in good Snowy Owl production (personal communication, J.F. Therrien). Dr. Therrien, a Senior Research Biologist at Hawk Mountain Sanctuary, Kempton, Pennsylvania conducted research in Quebec and Bylot Island, Nunavut, Canada, where he observed Snowy Owl nests. Many readers will recall the iconic photographs of nests that had as many as 70 uneaten lemmings ringing the nest.
Will some of the owls that travel to Massachusetts from the breeding grounds in the Arctic fail to make it back? Many young raptors, including Snowy Owls, don’t make it past their first year because it is difficult to survive to become an adult (presentation at a raptor research conference on gyrfalcon, ptarmigan, and other Arctic species in Boise, Idaho). One of the first Snowy Owls that showed up in Massachusetts in the winter of 2013–14 had a white wing tag A75; it had been banded in November 2012 by Dan Zazelenchuk in Kyle, north of Saskatoon, Canada. Unfortunately that owl was hit by a train and killed. In the winter of 2013–2014, we received 38 dead Snowy Owls that were found in Massachusetts. Several birds were emaciated, due not to lack of food in the Arctic or on their journey south, but rather due to their inability to hunt because of trauma, broken wings or legs, fungal infections, or parasites. Others were hit by trains, aircraft, or jet blast; were electrocuted, drowned, or poisoned with rodenticide.
Is something happening in the Arctic with climate change that is causing fluctuations in the Snowy Owl population? This is a question posed by the International Snowy Owl Working Group (of which I am a member) at its meeting in Russia in February 2014. Currently, lack of well-documented data hampers us from answering this and other questions. Are Snowy Owls declining in the Arctic? Can they adapt to the changes that are taking place in the Arctic? By continuing our research on Snowy Owls we may help to answer these and other questions in the future.
Norman Smith is a self-taught naturalist who has worked for the Massachusetts Audubon Society since 1974. His current position is Director of Blue Hills Trailside Museum and the Norman Smith Environmental Education Center in Milton, Massachusetts. He has studied birds of prey for over 40 years. His mission is to use the information gathered from his research to stimulate a passion in everyone he meets to help us better understand, appreciate and care for this world in which we live.