A Lesson in Careful Tree-Cutting

When Canadian biologist Chris Fisher drove through Banff, Jasper, Mount Revelstoke and Glacier national parks in May, he noticed that many trees were being cut down along the highways for various park projects. May is prime nesting season, so he wondered how the park service was managing not to disturb birds. After all, the Migratory Birds Convention Act prohibits killing, capturing, taking and disturbing of migratory birds or their nests from late April until mid-August. Wouldn't you be curious too?

Michael den Otter, an environmental assessment specialist with Banff, Yoho and Kootenay, confirms that safety upgrades, fence maintenance, and other infrastructure improvements are indeed requiring the cutting of trees along the highways, but he says that all the national parks are following the standards. “Most of the trees you see beside the highway were actually cut before the end of April. We try whenever possible to schedule our work so we’re not going into that bird breeding season.”

Sometimes it isn’t possible to schedule work so it doesn't interfere with nesting season, for instance in places where snow doesn't melt until quite late. In those places, there's a set of rules to follow that includes extensive nest sweeps. Biologists search for nests for three days during the week before cutting is scheduled. den Otter says, “If we find any sign of nesting birds, then that project will have to either mitigate that or it will have to be put on hold until whatever happens to be nesting there moves on.”

For example, a recent sweep found a dark-eyed junco along the Trans-Canada Highway during some tree removal in Yoho National Park. den Otter says, “We put a 100-meter buffer around that nest area and we’ll have to wait to complete that work in the fall when the bird fledges." A 100-meter buffer is higher than the standard, so it sounds like these folks are serious.

den Otter says the crews haven’t encountered many nesting birds in the areas along the highways where the work is being done. After all, it's a pretty noisy and disturbed area, not the deep, dense, old-growth forest that many birds really like. Still, dark-eyed juncos and white-crowned sparrows do prefer these edge habitats, and they are plentiful—and being allowed to do their thing while the projects wait. 

Fisher, the biologist, states that Environment Canada suggests not performing any nest sweeps in forested environments. “It’s their position that the likelihood of finding every single nest or the complexity of the habitat really makes it difficult to find all of the nests." He'd prefer that the national parks not even try to remove trees until after nesting season.