The tundra is a biome that is by far one of the coldest on earth, only really beaten out by the poles and the desert at night. Due to this, the adaptations required to live in this area tend to be the exact opposite of those required in the desert. Despite this, the same birds that tend to live all over the center of North America also live in the tundra. These birds are crows, swans, and falcons. This may look like it is caused by migration; however, this is only partially true. While all of these birds do migrate, some of them are sedentary and always live in the tundra. This is possible because all of them fill their own niche within the food chain of the tundra. Despite that, some birds, such as the snowy owl, still live in the tundra year-round because their adaptations make them only effective in a snowy environment.