SUNGREBE & FINFOOTS
The Sungrebe and Finfoots are a small family of odd aquatic birds locally distributed in the tropics around the world. There are three species -- each in a monotypic genus -- and each fills a niche in the major tropical regions of the world. I have as yet seen only one, and photographed none, but Marc Fenner kindly allowed me to use his fine shot of the Neotropic
(left). Marc took this photo in Costa Rica; my experiences are from eastern Venezuela and the Cayaru River, Peru (just across the river from Colombia); and the species ranges from Mexico to Argentina. The Sungrebe frequents quiet backwaters along freshwater streams and rivers, sometimes in the same habitat as the Sunbittern which shares a similar facial pattern (see my
). All species in this family have lobed feet -- an adaptation for aquatic life -- and feed primarily from the water by taking food items (crustaceans, amphibians, invertebrates fallen into the water) at the surface.
Species in family 3
Species observed [DR] 1 (33%)
Species photo'd [DR] 0
There are two finfoots in the Old World: the African Finfoot
which ranges widely throughout tropical and southern Africa but is nowhere common, and the endangered Masked Finfoot
of southeast Asia. All species are primarily resident, but the Masked Finfoot has an odd distribution of records in Peninsular Malaysia and Sumatra that suggests migratory movement. The latter bird is especially poorly known. [I have spent time in Kruger Nat'l Park, South Africa, waiting at a known finfoot site for the African bird -- which is sometimes known as "Peter's Finfoot" -- to appear, but without success.]
This lack of much basic information extends to all members in the group. In writing about this family, Bertrand (1996) says that "rather few bird families are as poorly known and as infrequently observed as the Heliornithidae." In my brief experience the birds were very shy and seen for only a brief time.
Young African Finfoots are born precocial and ready to swim, but baby Sungrebes are born blink, almost naked, and helpless. The Sungrebe is already very strange in having a very short incubation period (10-11 days, matching some small passerines) but has an astonishing behavior entirely unique in the bird world: the male Sungrebe is able to transport these helpless offspring, even in flight! Bertrand (1996) explains:
"M. Alvarez del Toro, who observed a nesting pair in Mexico, discovered that the male has a shallow pocket under each wing into which the two young can fit. The pocket is formed by a pleat of skin, and made more secure by the feathers on the side of the body just below. The heads of the chicks could be seen from below as the bird flew. Alvarez del Toro collected the bird in order to examine it and confirm the unlikely discovery. Subsequently, he found it confirmed also by a report published by Prince Maximilian of Wied 138 years earlier but apparently ignored, forgotten or not believed.
Yes, the Sungrebe and the finfoots are mystery birds indeed.
This adaptation is unique among birds: in no other species is there any mechanism whereby altricial young can be transported. Of course, the precocial young of some swans and grebes may hitch rides on their swimming parents' backs, and a male jaçana can transport his chicks about holding them between his wings and body, but neither of these cases applies when the adults are in flight....
The transport system of the Sungrebe raises numerous further questions. How do the chicks get into the pocket? Are they put in by the male? Does he feed them in there? Do they stay inside, or get in and out? Why does the female not have similar pockets? ...
: Marc Fenner photographed the swimming
at Tortuguero, Costa Rica, in March 1991. Photo
© 2000 Marc Fenner, used by permission; all rights reserved.
Other excellent photos of Costa Rican birds can be found on
Marc Fenner's Costa Rican web site
There is no "family book" per se of which I'm aware, but an good introduction to the family (with photos of all species in the wild) is in Bertrand (1996).
Bertrand, B. C. R. 1996. Family Heliornithidae (Finfoots) in del Hoyo, J., Elliott, A., & Sargatal, J., eds.
Handbook of the Birds of the World.
Vol. 3. Lynx Edicions, Barcelona.
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