This Week’s Creature Feature: White Blankets of Birds
Each year, vast flocks of white geese with black-tipped wings come from the tundra of Canada to spend the winter on the Eastern Shore. These are snow geese.
They are fairly large birds, and a flock can contain so many — several thousand birds — that it looks like a vast noisy white curtain being lifted as they take flight together. These flocks rise in the evening and morning, as they spend night in water, ponds or bay tributaries, and in the morning fly to fields to feed.
They eat grass and other vegetation and particularly enjoy grain left on fields by farmers. The birds are very cautious of hunters and will rotate feeding sites and avoid areas where they feel nervous.
The life of a snow goose starts in northern Canada above the timberline. In a grass nest lined with feather down, three to five eggs hatch after 25 days of incubation. Their parents, mated for life, became a pair around two years of age and started their first family on their third year. Both parents help with care for the goslings, which leave the nest almost immediately and feed on their own while under a parent’s close watch. They can start the annual 3,000-mile migration after six weeks.
Snow geese have two color phases, the common white phase with black-tipped wings and a rarer blue-goose phase. About one in 250 birds is a blue phase with a white neck and head but blue-gray body and orange bill and legs.
In the Hudson Bay area, the geese have been extending their range until they are considered overpopulated. Because they pull up plant roots as they feed, they are destructive to the tundra. Extended hunting seasons and bag limits are forms of population control.
Humans are not their only hunters. American bald eagles fly over the feeding or resting flock, which causes them to lift off with loud, panicked honking. Taking off in fright, the geese can collide into each other and occasionally break a wing, which is what the eagles seem to try to make happen.
One of the best places to witness the large winter migration is Blackwater National Wildlife Refuge.