Coots are medium-sized water birds that are members of the rail family Rallidae. They constitute the genus Fulica. Coots have predominantly black plumage, and, unlike many of the rails, they are usually easy to see, often swimming in open water. They are close relatives of the moorhen.

The greatest species variety is in South America, and it is likely that the genus originated there. They are common in Europe and North America.

They have prominent frontal shields or other decoration on the forehead, and coloured bills, and many, but not all, have white on the under tail. Like other rails, they have lobed toes. The featherless shield gave rise to the expression “as bald as a coot”, which the Oxford English Dictionary cites in use as early as 1430.
They tend to have short, rounded wings and are weak fliers, although northern species are nevertheless capable of covering long distances; the American Coot has reached Great Britain and Ireland on rare occasions. Those species that migrate do so at night.
Coots can walk and run vigorously on strong legs, and have long toes that are well adapted to soft, uneven surfaces.
These birds are omnivorous, taking mainly plant material, but also small animals and eggs. They are aggressively territorial during the breeding season, but are otherwise often found in sizeable flocks on the shallow vegetated lakes they prefer. A flock of coots is known in the US as a cover.