"American Coot is much more common in western North America than it is in the east, and in winter it forms dense wintering groups, even in small ponds such as those in golf courses. During the breeding season American Coot occupies marshes with a mix of open water as well as dense emergent vegetation. The nest is placed in a vegetated area, even a rather small one, and foraging takes place in the more open areas of the marsh. American Coot is an adept diver and feeds on aquatic matter from the marsh bottom. American Coot is migratory, with northernmost populations retreating considerably while southern ones are reinforced by birds from the north. All migration takes place at night, American Coot seldom is seen in flight; in flight, it shows a bold whitish trailing edge on the secondaries."
neotropical.birds.cornell.edu