American coot

Appearance

The American coot measures 34–43 cm in length and 58–71 cm across the wings. Adults have a short, thick, white bill and white frontal shield, which usually has a reddish-brown spot near the top of the bill between the eyes. Males and females look alike, but females are smaller. Body mass in females ranges from 427 to 628 g and in males from 576 to 848 g. Juvenile birds have olive-brown crowns and a gray body. They become adult-colored around 4 months of age.

Naming

The first evidence for parental selection of exaggerated, ornamental traits in offspring was found in American coots. Black American coot chicks have conspicuously orange-tipped ornamental plumes covering the front half of their body that are known as “chick ornaments” that eventually get bleached out after six days. This brightly colored, exaggerated trait makes coot chicks more susceptible to predation and does not aid in thermoregulation, but remains selected for by parental choice. These plumes are not necessary for chick viability, but increased chick ornamentation increases the likelihood that a chick will be chosen as a favorite by the parents. Experimental manipulation of chick ornamentation by clipping the bright plumes have shown that parents show clear preferences for ornamented chicks over non-ornamented ones.

Distribution

American coots are found near water reed-ringed lakes and ponds, open marshes, and sluggish rivers. They prefer freshwater environments but may temporarily live in saltwater environments during the winter months.

The American coot's breeding habitat extends from marshes in southern Quebec to the Pacific coast of North America and as far south as northern South America. Birds from temperate North America east of the Rocky Mountains migrate to the southern United States and southern British Columbia. It is often a year-round resident where water remains open in winter. The number of birds that stay year-round near the northern limit of the species' range seems to be increasing.

Autumn migration occurs from August to December, with males and non-breeders moving south before the females and juveniles. Spring migration to breeding ranges occurs from late February to mid-May, with males and older birds moving North first. There has been evidence of birds travelling as far north as Greenland and Iceland.

Status

The American coot is listed under "least concern" by the IUCN Red List of Endangered Species. They are common and widespread, and are sometimes even considered a pest. They are rarely the targets of hunters since their meat is not considered to be as good as that of ducks; although some are shot for sport, particularly in the southeastern United States. Because they are found in wetlands, scientists use them to monitor toxin levels and pollution problems in these environments.

Behavior

The American coot is a highly gregarious species, particularly in the winter, when its flocks can number in the thousands.

Habitat

American coots are found near water reed-ringed lakes and ponds, open marshes, and sluggish rivers. They prefer freshwater environments but may temporarily live in saltwater environments during the winter months.

The American coot's breeding habitat extends from marshes in southern Quebec to the Pacific coast of North America and as far south as northern South America. Birds from temperate North America east of the Rocky Mountains migrate to the southern United States and southern British Columbia. It is often a year-round resident where water remains open in winter. The number of birds that stay year-round near the northern limit of the species' range seems to be increasing.

Autumn migration occurs from August to December, with males and non-breeders moving south before the females and juveniles. Spring migration to breeding ranges occurs from late February to mid-May, with males and older birds moving North first. There has been evidence of birds travelling as far north as Greenland and Iceland.

Reproduction

The coot mating season occurs during May and June. Coot mate pairings are monogamous throughout their life, given they have a suitable territory. A typical reproductive cycle involves multiple stages: pairing, nesting, copulation, egg deposition, incubation, and hatching.
The American coot typically has long courtship periods. This courtship period is characterized by billing, bowing, and nibbling. Males generally initiate billing, which is the touching of bills between individuals. As the pair bond becomes more evident, both males and females will initiate billing only with each other and not other males or females. After a pair bond is cemented, the mating pair looks for a territory to build a nest in. A pair bond becomes permanent when a nesting territory is secured. Copulation behavior among coot pairs always falls under the same general pattern. First the male chases the female. Then, the female moves to the display platform and squats with her head under the water. The male then mounts the female, using his claws and wings to balance on the female's back while the she brings her head above the water. Sexual intercourse usually takes no longer than two seconds.The American coot is a prolific builder and will create multiple structures during a single breeding season. It nests in well-concealed locations in tall reeds. There are three general types of structures: display platforms, egg nests and brood nests.
⤷  Display platforms are used as roosting sites and are left to decompose after copulation.
⤷  Egg nests are typically 30 cm in diameter with a 30–38 cm ramp that allows the parents to enter and exit without tearing the sides of the nests. Coots will often build multiple egg nests before selecting one to lay their eggs in.
⤷  Brood nests are nests that are either newly constructed or have simply been converted from old egg nests after the eggs hatch. They are simply larger egg nests.
Since American coots build on the water, their structures disintegrate easily and have short life spans. Egg and brood nests are actually elaborate rafts, and must be constantly added to in order to stay afloat. Females typically do the most work while building.Incubation start time in the American coot is variable, and can begin anywhere from the deposition of the first egg to after the clutch is fully deposited. Starting incubation before the entire clutch has been laid is an uncommon practice among birds. Once incubation starts it continues without interruption. Male and female coots share incubation responsibility, but males do most of the work during the 21-day incubation period. Females will begin to re-nest clutches in an average of six days if clutches are destroyed during incubation.

Hatch order usually follows the same sequence as laying order. Regardless of clutch size, eight is the typical maximum size of a brood. Egg desertion is a frequent occurrence among coots because females will often deposit more than eight eggs. Brood size limits incubation time, and when a certain number of chicks have hatched the remaining eggs are abandoned. The mechanism for egg abandonment has not yet been discovered. Food resource constraints may limit the number of eggs parents let hatch, or the remaining eggs may not provide enough visual or tactile stimulation to elicit incubation behavior. An American coot can be forced to hatch more eggs than are normally laid. These additional offspring, however, suffer higher mortality rates due to inadequacy in brooding or feeding ability.

Food

The American coot can dive for food but can also forage and scavenge on land. It is omnivorous, eating plant material, arthropods, fish, and other aquatic animals. Its principal source of food is aquatic vegetation, especially algae. During breeding season, coots are more likely to eat aquatic insects and mollusks—which constitute the majority of a chick's diet.

Predators

The American coot is listed under "least concern" by the IUCN Red List of Endangered Species. They are common and widespread, and are sometimes even considered a pest. They are rarely the targets of hunters since their meat is not considered to be as good as that of ducks; although some are shot for sport, particularly in the southeastern United States. Because they are found in wetlands, scientists use them to monitor toxin levels and pollution problems in these environments.

Cultural

On the Louisiana coast, the Cajun word for coot is "pouldeau", from French for "coot", "poule d'eau" – literally "water hen". Coot can be used for cooking; it is somewhat popular in Cajun cuisine, for instance as an ingredient for gumbos cooked at home by duck hunters.

The bird is the mascot of the Toledo Mud Hens Minor League Baseball team.