Sungrebe (Heliornis fulica): Pato cantil; Zwergbinsenralle; Grébifoulque d’Amérique
This seems to be the first recorded sighting of the Sungrebe in our province. This lone female was first found by David and Meg West at Finca Tres Equis, a location that is fast becoming an indispensable stop for all birders visiting Turrialba. The species is the sole New World representative of the Heliornithidae family. As is often the case, its Spanish name in Costa Rica is a misnomer. It translates to ‘ravine duck’ in English, but while it is true that it frequently prefers steep-sided water courses in its lowland habitats, it is not a duck. Neither is it a rail, as its German name (‘dwarf bulrush-rail’) would suggest. In French it is a ‘grebe-coot’, which is perhaps not a bad description.
The Sungrebe can dive well but does so rarely. It often swims semi-submerged in the manner of an Anhinga and prefers not to fly. Its distribution ranges from southern Mexico down through Central America to southern Brazil. In Costa Rica it is considered a fairly common species in slow-moving streams of the Caribbean lowlands, but it is a rare find on the Pacific side of the country in the Osa Peninsula and Golfo Dulce region. The next image shows the Sungrebe‘s surprisingly small size when contrasted with one of our area’s commonest rails, the Russet-naped Wood-Rail:
Even more surprisingly, the standard field guides give an almost identical length of around 11-12 cm for both species! I find that length measurements for many birds, both for body and for wingspan, are not always good indicators of a species’ appearance in the field. In the case of the Sungrebe its tail accounts for about one third of its total length. Note also that male Sungrebes have white cheeks and that in general their plumage is not as bright as that of the females. The individual found at Finca Tres Equis is clearly a female:
Interestingly, care of the chicks, once hatched, is primarily the responsibility of the male. Another amazing fact is that the Sungrebe is said to be the only known bird species that has a pouch. It is located under the wing of the male, where he then shelters the chicks. For further details see the following link: https://commons.wikimedia.org/wiki/File:Heliornis_fulica_male_pouch_diagram.jpg
Birders from the USA should also be aware that the Sungrebe is steadily extending its range northwards through Mexico and has now already reached central Tamaulipas State. What are the chances of its appearance on the Texas side of the Rio Grande? Back in 2008 an individual even showed up at the Bosque del Apache National Wildlife Refuge in New Mexico.
I am again unlucky to find myself stranded in England just when this beautiful and enigmatic bird has been identified within close reach of my Turrialba home.