The word “grouse” actually refers to a whole family of birds, which includes the ptarmigan and the prairie chicken. These birds are all web-footed, which means they have four toes on each foot, and most of them are plump with round bodies. Most grouse also have feathers that are thick and stiff, and this helps to insulate them against the cold weather. The males of some species also have brightly coloured plumage, which they use to attract mates.