It has been a couple of years since I last saw a snowy owl and I miss being startled by a distant white object, I’ve taken for a snow patch suddenly taking wing and gliding low over the tundra. Snowy Owls are arcticophiles and I enjoy the years when they seem abundant across northern Alaska. It is not their population cycles which account for my seeing them or not and it isn’t that I haven’t been out birding on the tundra enough. Snowy Owls only breed in years of high lemming abundance and most of them breed near Barrow. So when they are busy catching literally thousands of lemming for their chicks near Barrow, we don’t often see them in places like the Arctic National Wildlife Refuge.
This boom and bust cycle of lemmings and owls affects more than my birding success; the variability in lemming numbers has profound effects on many types of arctic wildlife. Studies from across the arctic have shown that high lemming years are good for nesting waterfowl such as geese and ducks too. No, the geese haven’t given up pond weeds for a life of lemming hunting, but the hyper-abundance of lemmings affects arctic foxes in two very interesting ways, both of which are beneficial to waterfowl.
Foxes are the primary nest predator of ground nesting ducks and geese on the arctic tundra. Adult geese can protect their nest but the foxes still get a significant percentage of eggs. This dynamic changes on high lemming years. For one thing, foxes are preoccupied with hunting lemmings and largely satiated by eating rodents. This must be a great relief to eiders and geese who need not be quite so vigilant about the foxes. The other part of the dynamic involves the nesting owls. One study near Barrow found that in protecting their own nests from foxes and other nest predators, the owls inadvertently protect other bird nests nearby. The endangered Steller’s eider, won’t even initiate nesting in low lemming years. Apparently they “know” it isn’t worth the effort if the foxes are looking for eggs and there aren’t any owls to chase the foxes away.
This spring when I’m out walking the tundra or canoeing in Kasegaluk Lagoon, binoculars at the ready, part of me will be hoping I get too see “Ukpik” the snowy owl perched on a tussock, but the other part of me hopes the owls will on their breeding grounds near Barrow eating scores of lemmings and keeping the eiders safe from the foxes.
By Michael Wald