Ruddy Ducks are compact, thick-necked waterfowl with seemingly oversized tails that they habitually hold upright. Breeding males are almost cartoonishly bold, with a sky-blue bill, shining white cheek patch, and gleaming chestnut body. They dive to feed on aquatic invertebrates, especially midge larvae and feed most actively at night, so you’ll often see Ruddy Ducks sleeping during the day with head tucked under a wing and tail cocked up.

Unlike most ducks, they form pairs only after arriving on the breeding grounds each year. Males perform unusual courtship displays in which they stick their tails straight up while striking their bills against their inflated necks, creating bubbles in the water as air is forced from their feathers. They punctuate the end of the display with a belch-like call.

Usually silent, the female gives a nasal call to beckon her brood, a high-pitched call to ward off amorous males, and a hiss when threatened.

They are short-distance migrants moving in small groups of 5–15 individuals, usually at night. Ruddys follow several migratory corridors fanning to the southwest, south, and southeast from their northern breeding grounds.