Birds
Sungrebe
Heliornis fulica · also called sungrebe, american finfoot
The sungrebe is a small, shy, striped-necked waterbird that slips along the shaded edges of tropical American rivers and is easy to miss entirely. It is worth knowing about for one reason above all: the male has pockets of skin under his wings, and he carries his newly hatched chicks around inside them — swimming, diving, and even flying with the babies aboard. No other bird does this.
Overview
The sungrebe lives on slow rivers, oxbow lakes, and flooded forest from southern Mexico to northern Argentina. It is 26–33 cm long, brown above and pale below, with a boldly striped black-and-white head and neck, a sharp reddish bill, and lobed, yellow-and-black-banded toes. It eats insects, spiders, small crustaceans, snails, and seeds gleaned from the water and overhanging vegetation.
The wing pouches
The male has a shallow skin pocket under each wing, held closed by muscle. When the chicks hatch, he tucks one into each pouch, and he can then swim, dive, and fly while carrying them — so a startled sungrebe family can leave the water altogether. It is an ability unknown in any other bird.
Chicks that hatch helpless
Sungrebe eggs hatch after only about 10–11 days, one of the shortest incubations of any bird, and the chicks emerge blind and nearly naked. That is why the father has to carry them rather than lead them around.
A finfoot
The sungrebe is one of just three species of finfoot worldwide — one each in the Americas, Africa, and Asia — all slender, secretive birds of quiet wooded waterways.
Status
The sungrebe is Least Concern, widespread and not threatened, though it depends on undisturbed, well-vegetated waterways and declines where riverbank forest is cleared.
Sungrebe: common questions
Does the male sungrebe really carry chicks under his wings?
Yes, and it is the only bird known to do it. The male has a shallow, muscular pouch of skin beneath each wing, against the flank. When the chicks hatch, after an unusually short incubation, they are far too undeveloped to walk, swim, or follow a parent, so the father tucks one into each pouch. He can then carry them while he moves about, and remarkably he can still swim, dive, and fly with the chicks aboard, meaning a whole sungrebe family can escape a threat by flying off together. The behaviour was doubted for years until it was carefully documented.
Why do sungrebe chicks hatch so undeveloped?
Sungrebe eggs hatch after only about 10 to 11 days, which is among the very shortest incubation periods recorded for any bird. Hatching that early means the chicks come out blind, almost featherless, and unable to control their own temperature or movement. Most birds with such helpless young keep them in a nest and feed them there. The sungrebe's solution is different — the father becomes a mobile nest, carrying the chicks in his wing pouches until they have grown enough to fend for themselves, which combines the safety of being brooded with the ability to flee danger.
Is a sungrebe a type of grebe?
No, despite the name and a general resemblance. Sungrebes are finfoots, a small family of their own with just three species worldwide. They share lobed toes and a low-swimming habit with true grebes and with coots, but these are adaptations to the same lifestyle rather than signs of close kinship. The name sungrebe simply reflects that early naturalists thought it looked like a grebe that came out to sun itself along wooded riverbanks.
Where and how can you see a sungrebe?
It takes patience and quiet. Sungrebes live along slow, shaded, heavily vegetated stretches of rivers, oxbow lakes, and swamp forest from Mexico to northern Argentina, and they stick close to overhanging branches and tangles at the water's edge. They swim low with only the head and neck visible, keep to cover, and disappear at the first sign of a boat or a person. Birders usually find them by drifting silently along a forested river early in the morning and watching the banks, or by learning the bird's soft, low calls.