Inhabitants of large prairie marshes during the summer, these wary birds usually spend the winter on large lakes, bays, and estuaries. A major item in their diet is wild celery, which gives their flesh a rich taste; they are generally regarded as the best-tasting of North American waterfowl. In recent years their numbers have declined drastically, chiefly because of the draining of the large marshes they require to breed. Where they are still relatively numerous, their long, V-shaped flocks are a striking sight as they move from one feeding ground to another.