By David Cronenwett
It has grown quiet up on the Front recently. Although still ridiculously warm for the most part, diminishing hours of daylight and cool nights have chased many of our bird species far to the south. Still, the Big Event won’t happen for a while yet; the autumnal migration of Snow Geese (Chen caerulescens) to their wintering grounds. We rarely imagine this bird as an individual, since their breathtaking migratory displays are how they’re usually observed. Our time with the geese in Montana is rather short; a stunning but brief event that punctuates the transitional seasons here. And one day they mysteriously leave, just as we’ve become accustomed to their presence in the country. To many birders there is something disheartening about missing the migration. The seasonal changes feel somehow incomplete if we haven’t seen the biannual spectacle.
Migration itself is a strategy for dealing with the hardships of winter. Animals deal with the cold in different ways; some work frantically to store food, yet remain active all winter. Some retain calories on their bodies and enter dormancy like bears and many rodents. Others such as elk and moose work hard to endure the season however they can. Snow geese simply take flight to warmer climes. Each of these strategies has benefits and risks. With migration, many of those risks involve timing; for example, adequate food resources must be available when birds arrive to nest since there is no turning back.
Snow geese spend more than half of every year engaged in the task of moving from overwintering habitat to summer breeding grounds and can do so in impressive flocks of thousands. Birds that pass through Montana have several stopover locations, the best-known of which is Freezeout Lake Wildlife Management Area. The energy required to fly the 3000 miles for each vernal and autumnal migration is significant, so feeding done during the winter and post-breeding periods must be substantial enough to fuel their great journeys.
By the early twentieth-century, there was concern over the continued existence of the bird, which, like most wildlife had greatly diminished from unrestrained habitat destruction and overhunting of the day. In 1916, harvest bans on snow geese were implemented in large swaths of the U.S. and remained in place until 1975. Since then, the North American snow goose population has grown by about 300 percent. Researchers believe that greater food availability from grain fields in the bird’s wintering habitat coupled with a rapidly warming climate has allowed the species to flourish in a dramatic fashion.
There is now the serious problem of geese annihilating their nesting habitat due to great numbers living and feeding on the fragile Arctic tundra. In a strange twist to climate change, the consistently earlier breakup of sea ice is bringing hungry polar bears into contact with large colonies of nesting snow geese. The bears, who are losing the ability to hunt ringed seals from ice platforms, are now regularly observed searching for other sources of food. Approximately eighty-eight goose eggs is the caloric equivalent to one seal, so at least in the short term, this newly available resource should buy the polar bear some time. Also, egg predation will help reduce the bird population to levels more in line with the carrying capacity of its tundra breeding habitat. Still, the future of Arctic-dependent species of all kinds is very uncertain.
In November of last year, I was fortunate enough to be in Helena one night, when large numbers of snow geese swirled above the city. Light reflected off their bodies brilliantly and it was impossible not to notice them. I’d never observed so many of these birds in an urban setting; they seemed to be confused by a combination of low clouds and light from town. We watched them churning in the sky with the urgency, joy, mayhem and cacophony usually associated with migration. I remember feeling a powerful sense of sympathetic movement, of wanting to get up and go with them wherever that was. Other people were opening doors and windows to see, pulling over by the side of the road and commenting to strangers. It was as if the whole community was collectively pulled away from whatever it had been doing to witness one of nature’s great displays.
This undefinable affection our kind has for long-distance migrators like snow geese inspires a special kinship with them. These birds mark the passage of time in such a beautiful, dramatic way, it is difficult to be unmoved by it.