Ducks are surprisingly flexible when it comes to choosing a place to sleep. They’re capable of roosting on land or in water, and their sleeping locations typically depend on the temperature, weather conditions, and predator risk.
Most ducks prefer to sleep floating in ponds and lakes. However, some breeds like the Muscovy duck prefer to rest above ground on a log or perched area.
These ducks are capable of unihemispheric sleep, which means one half of their brain shuts down for sleep while the other remains active enough to recognize movement in their environment and respond accordingly. As such, ducks at the end of a roosting line will keep their eyes open for danger, waking the rest of their flock to move to another safer location.
As a gregarious and social species, ducks tend to sleep in large groups. The largest roosts are composed of hundreds and even thousands of Mallard ducks. Interestingly, Mallards are able to sleep while standing on one or two feet, or in a sitting position. They can also tuck their wings in and huddle for warmth, as many domestic ducklings do in the care of their mothers.
While most ducks are semi-nocturnal, they still feed during the day. In fact, some studies have found that waterfowl feeding activity is greater during the day than at night. This is probably due to a combination of factors, including the weather, predation risks, and the availability of food sources.