The Snowy Owl, also known as the Snow Owl, Snowy White Owl, and the Arctic Owl, is a fascinating bird and one of the largest owls in the world, A massive animal, with the females weighing in at 6.5 pounds and a wingspan of 61 inches, 35% bigger than the males, which are still a large 4.5 pounds with a wingspan of 56 inches. These owls live nomadic lives on the remote, treeless, windswept Arctic Tundra.
Snowy Owls hatch out of ground based nests on raised mounds near the tundra ponds, streams, or even the ocean. They are considered indicator species of the Arctic habitat, including many other animals such as Arctic foxes, polar bears, musk oxen, loons, and dozens of other species. The closest living relative to the Snowy Owl is the Great Horned Owl – but Snowy only show the ear tufts when flying into the wind or sitting on the nest, unlike the prominent tufts seen on the Great Horned Owls. It is thought that these specialized feathers act primarily to break up the shape of the female while she sits on the nest helping to camouflage her, and actually have little to nothing to do with hearing.
Originally, Snowy Owls were thought to be 2 species, because they demonstrate sex-specific feather patterns, which is very uncommon amongst owls. A close look at their natural history, however, explains some potential reasoning for this dimorphism. The females are not only larger, but also sport a speckled black or tan patterning on a white base color. When they are sitting on the nest, this coloring allows them to blend in with the dappled environment of the tundra, where snow can be present through most of the breeding season. The males, on the other hand, are both smaller and have primarily white coloring. While the female does the entirety of the incubating and chick rearing (and thus needs to camouflage into the tundra), the male is responsible for providing food to the family, and can easily retreat into a snowy area or snowbank to hide from threats.
This bird is incredibly adapted to survive some of the harshest conditions on the planet, where temperatures routinely plunge to 40 below zero and intense winds prevail. Not only is the weather harsh and unpredictable, but so is the food supply. Snowy Owls have feathers covering their feet to protect them both from the cold and the bites of their primarily rodent prey. The feathers around their bill and nostrils are thickened and dense rectal bristles, which not only hide and camouflage the black bill, but also provides a way to warm the air before it is breathed into the airways. Although they do have the traditional owl “facial disk” made up of stiff feathers around the face which are connected by muscular flaps, enabling them to change the shape of the disk to better capture faint sounds, they rely heavily on their excellent long-distance eyesight, reportedly able to visually identify prey moving on top of the snow from as far as a half mile away!
Many humans will never see a wild Snowy Owl other than during the winter season, when they may choose to leave the arctic, sometimes in large numbers known as “irruptive years”. It is unclear what causes these irruptions, but probably multiple factors are involved, including the prior year’s breeding success, snow depth, and the abundance of prey. During these times of irruption, Snowy Owls will appear throughout Canada and down into the upper portion of the United States as well. In massive irruptive years, birds have been found all the way down as far as Bermuda! If they are going to leave the Arctic, it will usually be during the October to January time period, and the young owls are most likely to wander looking for alternative winter housing. They will return in February through April, with the adults heading back home first. On their home turf, they survive primarily on lemmings, with the addition of occasional ptarmigan, hares, sea ducks, or songbirds added into the diet. Everything from the size of a snow bunting up to an eider is fair game! During the winter months, they are much more opportunistic, including in their diet mice, pigeons, carrion, foxes, and whatever they can catch or scavenge. Most birds will need to consume 10-25% of their body weight per day.
Lemmings are a keystone in the lifecycle of the Snowy Owl. Not only are they the primary food source, but they are important for the mating display. The male will stockpile lemmings early in the breeding season – and these will be fed to the female once she is sitting on the nest, and later, will be given to the female who will then feed the young. She will judge his hunting ability during the mating season – and he shows off his prowess by waving around a nuptial gift of a lemming. Desperate males have been seen to wave around frozen pieces of turf during the mating ritual, which does not particularly impress the females! Lemmings undergo unpredictable booms and bust in their population cycles, which can lead to dramatic reductions in reproductive success for the birds.
Snowy Owls are relatively long lived, surviving 20+ years in the wild and 30+ years in captivity. They will typically not breed until they are about 4 years old and will often attempt to bring 4-8 chicks to fledging. This means a lot of lemmings that needs to be caught by the male to support the family, so his hunting prowess is critical to the success of the pair. Although typically considered diurnal, these owls are most commonly active in the early evening through to the early morning (more of a nocturnal schedule) but the activity will depend on the weather and prey activity. Most birds will avoid hunting in windy, rainy conditions and will readily alter their schedules accordingly. They are quite territorial, and will drive off other Snowy Owls, as well as species such as ravens and even foxes that enter their turf.
Snowy Owls are regularly seen in small numbers throughout the northern US and in some spots in Maine – and I strongly encourage anyone that has the opportunity to sit and watch these fascinating visitors from the arctic to spend some time with them and ponder the difficult conditions in which they not only survive, but thrive!
