Least Grebe, Tachybaptus dominicus

The Least Grebe (Tachybaptus dominicus) is an aquatic bird. It is the smallest member of the grebe family. It occurs in the New World from the southwestern United States and Mexico to Chile and Argentina, and also on Trinidad and Tobago, the Bahamas and the Greater Antilles.

It ranges in length from 21 to 27 cm and in weight from 112 to 180g. Just like all grebes, its legs are set far back on its body and it cannot walk well, though it is an excellent swimmer and diver. Small and plump, with a fairly short, sharp pointed beak and bright yellow eyes, it typically appears quite dark all over. A breeding adult is grey above with a darker blackish throat and crown. Its chest is brownish and its underparts are pale. In flight, it shows a white wing patch. Non-breeding birds are paler with a whitish throat, and the immatures are paler and greyer than the adults. Unlike the other members of its genus, it lacks any chestnut coloring on its neck.

There are five recognized subspecies of Least Grebe and they are separated principally by size and color. T. d. dominicus is found in the northern Caribbean, including the Bahamas, Greater Antilles and the Virgin Islands. T. d. brachypterus can be found from southern Texas and Mexico south to Panama. T. d. bangsi is limited to southern Baja California, Mexico. It’s the smallest and palest of the subspecies. T. d. speciosus can be found in South America, from Columbia, Venezuela, Trinidad and Tobago south to northern Argentina and southern Brazil. T. d. eisenmanni is limited to the lowlands of western Ecuador. This subspecies isn’t recognized by all authorities.

Its genus name, Tachybaptus, is a blend of two Greek words-takhus meaning fast and baptos meaning diving, or sinking under. The specific name dominicus refers to the Caribbean island of Hispaniola, which was previously known as Santo Domingo. As its English name insinuates, the Least Grebe is overall the smallest member of the grebe family. It’s the only member of its genus found in the New World; the four other members of the genus Tachybaptus exist in the Old World and Australasia.

The Least Grebes are found in a wide assortment of wetland habitats, including freshwater ponds, lakes, and marshes, slow-flowing streams and rivers, roadside ditches, and mangrove swamps. In general, they prefer bodies of water with significant amounts of vegetative cover, especially along the edges; they will even use wetlands which are almost completely overgrown. They might choose small, temporary bodies of water to breed, in an effort to evade predation of their chicks by large fish.

For most of the year, Least Grebes are found single, or in pairs; however, when they aren’t breeding, they sometimes gather in flocks of 20 or more.

The Least Grebe eats a range of aquatic life, including small fish, crustaceans, frogs and aquatic insects. Just like all grebes, it pursues much of its prey under water. During active feeding bouts, it spends on average 12.5 seconds beneath the surface on each dive, with surface pauses stretching from 2 to 24 seconds.

These birds breed throughout the year. Those in tropics have a tendency to breed during the rainy season, while active nests have been found in every month of the year in Texas. Each pair constructs a compact floating nest of vegetation-usually a variety of aquatic weeds-which is anchored to rooted plants in still open water as deep as 5 ft. The female lays three to six white eggs, though the damp nest material soon stains them with a brown color. Both of the adults incubate the eggs, which usually hatch after 21 days. The young are striped and sometimes carried on the adults back.

The breeding call has been described as a horse whinnying.

The Least Grebe is at risk from a number of predators, especially early in life. Large fish species and turtles are known to take young grebes, and bird-eating raptors, including the Bat Falcon, have been observed taking adult birds.

Image Caption: Least Grebe (Tachybaptus dominicus). Credit: Len Blumin/Wikipedia (CC BY 2.0)