The Potoo Bird
Strange Master of Camouflage

Do you notice anything unusual about the photo of tangled Amazonian trees below? Look for the bird: the potoo.

You probably see it by now. If you don’t, look at the close-up below. What looks like the broken end of a branch is a juvenile Common Potoo, sitting upright, perfectly still, pretending to be part of the tree.

Potoos are a small family of nocturnal birds, the Nyctibiidae, found only in the tropics of the Americas. For a long time they were lumped in with the nightjars, which they resemble, but they are now placed in an order of their own, and their closest living relative is the strange, cave-dwelling oilbird. By day they sleep in plain sight on exposed branches and stumps; by night they become ghostly hunters of flying insects, filling the forest with some of the most haunting calls in the natural world.

How Potoos Hide in Plain Sight

A potoo’s whole daytime life is a performance. It chooses a perch roughly the same diameter as its own body, usually a broken branch or the top of a stump, and settles onto it vertically, with its head tilted up and its bill pointed at the sky. Its mottled gray, brown, black and white feathers match the bark, and when it senses danger it freezes, stretching even taller and thinner so that it looks like one more dead snag in the canopy. Biologists call this masquerade: rather than hiding behind something, the bird pretends to be something else.

The disguise has one clever detail. A potoo’s eyes are enormous, and wide open they would give it away. So during the day it keeps them closed, but it has small notches in its upper eyelids that let it keep watching for movement while its eyes appear shut. The smallest species, the Rufous Potoo, takes the act even further: it is bright orange-red with white spots, and it roosts low in the forest, swaying gently like a dead leaf caught on a twig.

How Many Potoo Species Are There?

There are seven species of potoos. They range from Mexico and the Caribbean to northern Argentina, with the greatest variety in the Amazon, where five of the seven can be found.

• Great Potoo (Nyctibius grandis): the largest potoo, up to two feet long with a wingspan approaching three feet. It ranges from southern Mexico through Central America and across tropical South America to Bolivia and southeastern Brazil, and it is famous for its deep, moaning growl.
• Long-tailed Potoo (Nyctibius aethereus): a large, long-tailed potoo of lowland rainforests, found in the Amazon Basin, the Chocó of Colombia, and a separate population in the Atlantic Forest of southeastern Brazil, Paraguay and Argentina.
• Common Potoo (Nyctibius griseus): the most widespread potoo, from Nicaragua to Argentina and on Trinidad and Tobago, and the one you are most likely to see. Its mournful, falling song is one of the classic night sounds of South America.
• Northern Potoo (Nyctibius jamaicensis): the northernmost potoo, from Mexico to Costa Rica and on Jamaica and Hispaniola. It looks almost identical to the Common Potoo, and was only recognized as a separate species in 1995, thanks to its completely different, harsh kwaaah call.
• Andean Potoo (Nyctibius maculosus): the mountain potoo, living in cloud forests of the Andes from Venezuela to Bolivia, usually between about 6,000 and 9,000 feet. It is rarely seen and known from relatively few sites.
• White-winged Potoo (Nyctibius leucopterus): the most mysterious of the potoos, a small species of the Amazon canopy and a tiny area of Brazil’s Atlantic Forest, named for the white patches on its wings.
• Rufous Potoo (Phyllaemulor bracteatus): the smallest potoo, about eight to ten inches long, found in Amazonian forests on poor, sandy soils from Colombia and Venezuela to Peru and Brazil. It is so different from the others that it has been placed in a genus of its own, whose name means ‘leaf imitator.’

What Do Potoos Eat?

Potoos are nocturnal insectivores, acting very much like flycatchers of the dark. At dusk they wake, open their eyes, and move to an exposed perch, where they sit and wait. When a large insect flies past, they sally out, snap it out of the air, and return to the same perch. Beetles make up much of their diet, along with moths, katydids, grasshoppers and flying termites. They hunt by sight, and their huge eyes shine brightly in the beam of a flashlight.

A potoo has a tiny, delicate bill, but an enormous mouth. When it opens, the gape stretches nearly the width of its head, like a feathered net. One ornithologist described potoos as little more than a flying mouth and eyes. The Great Potoo occasionally takes larger prey, and has been recorded catching bats and small birds.

Do Potoos Build Nests?

Potoos don’t build nests at all. The female lays a single white egg, speckled with purple-brown, in a small depression on top of a broken branch or rotten stump, often the same kind of perch the adults use to hide during the day. Both monogamous parents take turns incubating, sitting upright over the egg in their stump posture, for about a month. The chick stays on the branch for about two more months, fed insects by both parents, and it has its own disguise: fluffy and pale, it sits motionless and looks like a clump of fungus or lichen growing on the wood.

The Voice of the Potoo

If you spend a night in a tropical forest, you are more likely to hear a potoo than to see one. The Common Potoo sings a slow series of up to eight whistled notes, each lower and softer than the last, one of the loneliest sounds in nature. The Great Potoo produces a guttural, moaning roar, the Northern Potoo a harsh, squalling kwaaah, and the White-winged Potoo a haunting, descending whistle.

These eerie songs have made potoos the subject of legends across South America. In Brazil, Paraguay and Uruguay the bird is called urutau, from a Guaraní word often translated as ‘ghost bird.’ In Argentina it is known as the kakuy, and in Bolivia as the guajojo, after its call. Many of the stories tell of a grieving person transformed into a bird, a child calling for lost parents, or a woman calling for a lost husband, still crying out in the night.

An Ancient Family

Today potoos live only in the American tropics, but they were once far more widespread. Fossils of a potoo-like bird called Paraprefica have been found in the Messel Pit in Germany, in rocks roughly 47 million years old, from a time when Europe was warm and forested. The seven living species are the survivors of a very old lineage of night birds, whose closest living relative is the oilbird of the Andes and northern South America.

Where to See Potoos

Because they sit still all day, potoos are surprisingly reliable once someone has found their roost, and many lodges and local guides in the tropics know exactly which branch a potoo has been using, sometimes for months or years. The Common Potoo is widespread in forest edges, plantations and even city parks from Central America to Argentina, while the Great Potoo is often found along big rivers in the Amazon, like the Napo, where I photographed the bird above. At night, the easiest way to find one is to scan the treetops with a flashlight for the orange glow of their eyes.

Like so many forest birds, potoos depend on large, old trees and intact forest, and several species are declining as their habitat disappears. They are a good reminder of how much life is hidden in a tropical forest, often in plain sight, if you know how to look.