Search Nature Watch

Tuesday, April 19, 2016

Mud Hens

American Coot, Fulica americana

Spend any amount of time observing wildlife around freshwater wetlands, swamps, marshes, suburban lakes, and sewage ponds, and you’ll no doubt see a Mud Hen or American Coot (Fulica americana).  Commonly mistaken to be ducks, coots belong to a distinct scientific order and differ significantly from other species of marsh birds.

An overall blackish, plump, chicken-like bird with a rounded head, red eyes, a sloping whitish bill with a dark band near the tip, and a small reddish brown forehead shield, coots swim like ducks but do not have webbed feet like ducks.  Their yellow-green legs end in long toes with broad lobes of skin on either side that help them kick through the water.  Each time the bird lifts its’ feet, the lobes fold back to facilitate walking on dry land.  Their tiny tails and short wings make them awkward and clumsy fliers, and they often require many wing beats and long running takeoffs to get airborne. Coots mainly eat aquatic plants and can dive in search of food, but they can also forage and scavenge on land for terrestrial plants, arthropods, fish, insects, and mollusks.  

Note the lobed feet on this perching American Coot

Mating season occurs in May and June, with coots requiring heavy stands of aquatic vegetation along a shoreline with some standing water within those stands.  It is here that they make their nests, which consist of multiple structures used as display platforms, egg nests, and brood nests. Egg nest material is woven into a shallow basket and lined with finer grasses to hold the eggs. The entire nest is anchored to upright plant stalks and is generally a floating structure.  Females deposit eggs between sunset and midnight, one per day, until the average clutch of 9 eggs is complete. Both males and females share the 21-day incubation responsibility.  

Being persistent re-nesters, coots will replace lost clutches within 2 days during the deposition period.  Additionally, once hatching begins and a certain number of chicks are present, coots will abandon the remaining eggs.  Unlike the drab color of the adults, coot chicks are quite colorful, having conspicuous, orange-tipped, ornamental plumes covering the front half of their bodies, often referred to as ‘chick ornaments.’   While these plumes get bleached out after about 6 days, experiments have shown that chicks with more of this ornamentation are given preferential treatment by their parents. The oldest known coot lived to be more than 22 years old.

In winter, coots can be founds in large groups or ‘rafts’ of mixed waterfowl and in groups numbering thousands of individuals.  They can consume very large amounts of aquatic vegetation, but because they live in wetlands, they can accumulate toxins from pollution sources including agricultural runoff, industrial waste, and nuclear facilities.  As such, scientists monitor coots as a way of measuring the effect these toxins have on the health of the environment at large.