By Marcy Mahr
My fascination with Snowy Owls (Bubo scandiacus) began with a close encounter of the bird kind one winter day in the mid-1980s while I was in college in Vermont. I was studying in the library when I heard a soft thud against the window. I looked up from my book right into the backside of a Snowy Owl. I remember my heart racing as I watched the 2-foot high bird tuck itself up against the glass on the third story window sill. It was such a beautiful creature. I hoped it wouldn’t see me through the glass as I studied its pure white feathers with small dark scallops; its thickly-feathered feet that looked like toasty down booties. The owl was squatting and snuggling to keep out of the wind, occasionally doing a bit of preening and shifting of feet. Its head was very large and round; no ear tufts. Its overall shape was squat and very smooth. This owl looked intently outward, scanning the snow-covered lawn in front of the building and beyond. When it was time to leave for my next class, I left the library and slowly walked around the building to see the owl. As I turned the corner, the Snowy was still there, and I distinctly remember feeling targeted by the intensity of its yellow eyes, that piercing stare of a raptor that unmistakably says, “I see you.”
Until just a few years ago, the Snowy Owl was regarded as the sole member of a distinct genus, Nyctea (as in Nyctea scandiaca), until DNA testing showed that it is very closely related to the horned owls in the genus Bubo. Depending on where you live, the Snowy Owl has many common names, such as Arctic Owl, Great White Owl, Ghost Owl, Tundra Ghost, White Terror of the North, and Ookpik. If you’ve ever tried to follow this large, nearly white bird in flat, winter lighting you know it is phantom-like in nature—one moment there’s an easily recognizable Snowy Owl and the next moment there’s a swirl of snow or low hanging cloud.
Snowies are typically found in the circumpolar North and tend to summer north of latitude 60 degrees north. Their coloration renders them well-suited for life north of the Arctic Circle. Adult males are nearly pure white, and females and young birds have dark scalloping. They winter throughout Canada and northern Eurasia, with birds occurring further south in some years depending on weather and availability of prey. This species has a large geographic range, with an estimated global extent of occurrence of 1-10 million km². The global population of Snowy Owls is estimated to be 290,000 individuals. Global population trends have not been quantified, yet populations appear to be stable. According to the IUCN Red List of Threatened Species, which is the main rule-book for assessing the extinction risk of species, the Snowy Owl is evaluated as a species of ‘Least Concern.’ The Snowy Owl is not believed to be approaching the thresholds for the population decline criterion of the IUCN Red List—a population declining more than 30% in ten years or three generations—according to an assessment made in 2004 by BirdLife International (the IUCN’s official Red List authority for birds).
Snowy Owls generally nest on the ground in areas free of snow with good visibility and ready access to hunting. They breed in May; depending on prey availability, clutch sizes range from 5-14 eggs laid singly over the course of several days. The pure white hatchlings emerge about five weeks after laying and are tended by both parents. As the young birds mature, they develop dark speckling and bars.
The Snowy Owl’s flight is typically strong, steady and silent. A Snowy Owl can rotate its head up to 270 degrees, and its head frequently swivels as it flies. Its eyes are ever watchful and scanning for prey, ready to pounce. These owls are highly diurnal, although they may hunt at night as well. Prey are captured in their talons on the ground, in the air, or snatched off the water. They transport bigger prey with their talons, while smaller prey is carried in their beaks. Snowy Owls rely on lemmings, voles and other rodents throughout most of their Arctic and wintering range. They can be opportunistic and also feed on young ptarmigans and other birds, as well as small mammals, fish and carrion. They also are known to follow traplines and raid bait from the traps.
Many Audubon members may remember the abundance of Snowy Owls in the Flathead and Mission valleys during the winter of 2005-2006. Reasons for this tremendous ‘irruption migration’ (as scientists call the phenomenon) remain unknown. Biologists at the Owl Institute based near Ninepipes studied the diet of Snowies that winter and found voles made up about 95% of their diet. In contrast, only three Snowy Owls were reported during last winter 2006-2007. How many might we see this winter? Keep your eyes scanning for this “Ghost Owl” and tell Flathead Audubon what you find.