As one of the continent's most familiar wetland birds, the plump, dark-gray, chicken-like American Coot (hereafter, coot), with its black head and neck and distinctive white bill and frontal shield, is easily the most aquatic, most abundant and widely distributed species of rail in North America. As a regular short- to medium-distance migrant, this coot may be found at one season or another in almost any of a broad variety of wetlands, including freshwater lakes, ponds, marshes, roadside ditches, and industrial-waste impoundments, as well as in coastal marine habitats. It breeds almost exclusively in freshwater marshes, with the largest breeding concentrations in the Prairie-Pothole Region of the southern Canadian Prairie Provinces and north-central United States. Inland reservoirs and other large bodies of open water are frequently used in winter, with coots often forming large rafts of many thousands of individuals.
An awkward and often clumsy flier, the coot requires long running takeoffs across the water's surface to become airborne. It is, however, an accomplished swimmer and diver, maneuvering underwater with the aid of lobately webbed toes. Although the coot will consume grains, grasses, and agricultural crops on land, it generally forages in or under water, where it is almost exclusively an herbivore.
This is a raucous and quarrelsome bird whose presence is often announced by its loud cackling, grunting, and croaking calls from deep within tall stands of emergent aquatic vegetation, particularly cattails, reeds, and bulrush. Its floating nest is anchored to emergent stems within these macrophyte stands, and monogamous pairs aggressively defend nesting territories against many other species of aquatic birds and, particularly, conspecifics. Hatchling coots are gaudily colored and semiprecocial, usually leaving the nest within a day of hatching to accompany their attentive parents, which initially feed and then assist their growing young in foraging.
An extensive series of excellent studies of various aspects of coot reproduction has laid the groundwork for this species to serve as a model for better understanding the adaptive value of variable strategies of energy allocation, conspecific nest parasitism, and other aspects of breeding biology under varying environmental conditions. Molecular genetic studies are needed to help identify breeding and wintering populations across the continent, as well as to clarify uncertain taxonomic relationship, status, and classification of the American Coot, Hawaiian Coot (Fulica alai), and Caribbean Coot (F. caribaea). A separate companion account for the Hawaiian Coot is appended to this account. All information in this account, unless indicated otherwise, will refer to the North American subspecies F. americana americana, with comparative information being presented for the lesser-studied Colombian Coot (F. a. columbiana) when available and only if differing from natural-history information for nominate F. a. americana ( Fjeldså 1983a ).