Built to tackle tricky cones, red crossbills are uniquely suited to winter survival.
Like colourful ornaments in forests of Christmas trees, red crossbills brighten the winter scenery, sometimes materializing in great numbers where none have been in recent years. They wander widely across the country in nomadic flocks, touching down and often nesting wherever they find bounties of conifer cones, even when the snow lies deep.
A crossbill can dine on unopened evergreen cones, impenetrable to other birds, by prying apart their scales with its misaligned beak tips and licking out the seeds. Crossbills often hang upside down as they rifle through the dangling cones and use their beaks to help them nimbly climb from one branch to another.
Ten varieties of red crossbills occur across North America, each with a different beak best suited for specific kinds of cones. Each also has a unique chipping flight call, ensuring that flocks almost never interbreed, suggesting they may define separate species. The most familiar crossbill in Eastern Canada is a little bigger than a house sparrow and favours pine and white spruce cones.
Highly variable regional cone crops drive crossbill wanderings. Last winter, a low-yield year west of the Rockies—the continent’s crossbill heartland—paired with the best spruce and pine cone crops in two decades in the east spurred a major invasion of western birds. These perceptibly smaller visitors relish hemlock and spruce cones whether at home or abroad.
Crossbills breed in summer, when spruce cones ripen, but often break into song again and nest through winter, sometimes raising two more broods if enough cones remain. Well-concealed year-round amid dense evergreen boughs, yellow-tinted nesting females steadfastly warm their eggs in the winter, and hatchlings are fed regurgitated seed pulp by their red-jerseyed fathers.
What’s with that beak?
Crossbills use their beak to clip cones from branches. After they use the overlapping tip to lever and pry scales open, they crack the seeds inside their bill and spit out the husk.