The sungrebe (Heliornis fulica) is a small aquatic gruiform found in the tropical and subtropical Americas from northeastern Mexico to central Ecuador and southern Brazil.
It is the only living member of the genus Heliornis. The family Heliornithidae, to which it belongs, contains just two other species: the African finfoot, Podica senegalensis, found in the Afrotropics from Sub-saharan West Africa and the Congo Basin through the Great Lakes' western shores to Southeast Africa, and the Asian or masked finfoot Heliopais personatus, found from eastern Indomalaya down through Sundaland to the Wallace Line.
These waterfowl have broad lobes on their feet, convergent to that of grebes or coots, that they use to propel themselves in the water. They are reclusive birds, preferring well-covered slow-flowing streams and secluded waterways, sometimes swimming partly submerged, like an Anhinga.
Sungrebes are unique among birds in that males have "pouches", folds of skin under their wings in which they carry their young from hatching until the chicks are able to swim for themselves. This has led to them being called "Marsupial Birds"
Taxonomy
The sungrebe was described by the French polymath Georges-Louis Leclerc, Comte de Buffon in 1781 in his Histoire Naturelle des Oiseaux from a specimen collected in Cayenne, French Guiana. The bird was also illustrated in a hand-coloured plate engraved by François-Nicolas Martinet in the Planches Enluminées D'Histoire Naturelle which was produced under the supervision of Edme-Louis Daubenton to accompany Buffon's text. Neither the plate caption nor Buffon's description included a scientific name but in 1783 the Dutch naturalist Pieter Boddaert coined the binomial name Colymbus fulica in his catalogue of the Planches Enluminées. The sungrebe is now the only species placed in the genus Heliornis that was erected by the French naturalist Pierre Bonnaterre in 1791 with the sungrebe as the type species. The name of the genus combines the Ancient Greek hēlios meaning "sun" and ornis meaning "bird". The specific epithet fulica is Latin for "coot". No subspecies are recognised.
There is some debate where the finfoot family, Heliornithidae, fits within Gruiformes. The Sibley–Ahlquist taxonomy of birds, based on DNA-DNA Hybridization, suggested that they are sister taxa to limpkins, the Aramidae, and even placed the limpkins within Heliornithidae in 1990. However, more recent genetic analyses suggests that limpkins are sister taxa to cranes, the Gruidae, and that finfeet are instead sister taxa to rails, the Rallidae. Other studies suggest that finfeet and the Afro-Madagascan flufftails, a group originally thought to be nested within rails, form a lineage called Sarothruridae that separated from each other at the end of the Eocene, probably in Africa. Sarothruridae, in turn, is considered a sister clade to Rallidae.
Within Heliornithidae, sungrebes are sister to the Asian finfoot, rather than the geographically closer African finfoot, according to the results of both Mitochondrial and Nuclear DNA sequencing. This adds credence to the idea that finfeet moved from an African origin into Eurasia and then across Beringia and through North America to reach South America, rather than coming across the Atlantic from Africa, or having evolved on Gondwana, separated with the shifting of the continents, and moved north into Laurasia from there. This would also explain the absence of finfeet from Australia, and the success of the Sungrebe at colonizing the continental Neotropics while failing to colonize any major Caribbean islands that do not have glacial land bridges to the mainland.
Description
The female is a small, slim bird, averaging about in length. Sungrebes have lobed toes, and the bare skin of their feet and legs are boldly banded in yellow and black. The body plumage is mostly varying shades of reddish brown, while the head and neck are strikingly patterned with a black crown and nape and white stripes along the sides of its neck, as well as a white throat and chin. The long tail (almost a third of the total length) extends well beyond the body in flight, and sits fanned out on or just below the surface of the water while the bird swims. Females have a rufous patch on the side of the face that brightens to a cinnamon-orange color during the breeding season. Also during the breeding season, her eye ring becomes brighter in color and her lower mandible goes from dark red to bright scarlet. Slightly shorter on average than the male, with a slightly shorter wingspan, , but slightly more powerfully-built with a higher average mass, .