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Rediscovered: White-winged Potoo

White-winged Potoo Common name: White-winged Potoo Scientific name: Nyctibius leucopterus Range: Amazonian Brazil Date thought extinct: One known museum specimen ca. 1821 Date rediscovered: 1993 Status: Not threatened

Potoos are nocturnal birds, spending the day perched in a tree looking very much like a broken branch. If disturbed during the day, potoos will point their bills towards the sky, flatten their cryptic feathers, and then not move a muscle. The impersonation of a dead branch is then complete, and most intruders will quickly move past without ever noticing anything other than the "broken branch." This behavior has earned them the name pájaro estaca—"wooden stake bird."

At night, potoos come alive. They use their large eyes, gaping mouth, and long wings to fly from their perch to capture flying insects. Sometimes they will catch insects from the leaves and branches of trees, but they are reluctant to forage for food on the ground where they would soon be vulnerable to other predators. When not hunting, potoos produce a haunting call from their perch, usually under moonlit skies. These calls—long, single tones that trail off after a few seconds—allow bird watchers and researchers an opportunity to track these interesting birds, and in some cases call them into view.

The white-winged potoo had been described by Maximilian zu Wied in 1821. Weid was a naturalist and ethnologist who led two major scientific expeditions to the New World in the early 1800s. His was the first and only known specimen of the bird, found in Brazil.

Rediscovery

Jan P. Smith, an ornithologist and bird bander, had reported seeing the potoo in October of 1985. Although Mario Cohn-Haft had heard of the sighting, he filed it in the back of his mind as one of the many neat birds that others had seen. Cohn-Haft, working on the Biological Dynamics of Forest Fragments Project in 1989, was assuming Smith's role there as a bird bander—he was not specifically on the trail of the white-winged potoo.

It is difficult to climb trees at night, and especially unsettling to do so when a thunderstorm is approaching. Such was Cohn-Haft's situation the evening of August 14, 1989. His thoughts sometimes drifted and a smile would appear on his face. He was new to South American ornithology, but he knew that he was going to continue working in the Amazon for a long time—he was hooked.

That evening, Cohn-Haft had been hearing long, descending whistled glissandos, repeated three or four times. He began imitating the calls, which he suspected to be that of a potoo. A small potoo flew into a tree, next to his camp. It smaller than the common potoo, N. griseus, and had a distinct white band on the wing.

"Wow, Smith was right! The white-winged potoo exists!" Cohn-Haft thought, recalling his colleague's sighting four years ago. Continuing to call, Cohn-Haft lured two birds in close enough to identify each as white-winged potoo.

He noted that the potoos preferred to perch upright, high up in the canopy on emergent snags and exposed branches. The long hours sitting in the canopy paid off. If he called the birds from the ground, he wasn't able to coax them close enough for good observations. On the other hand, when he whistled and called to the birds while he himself was perched high in the trees, he could observe the birds fly within a few feet—one actually perched within about 20 feet (seven meters) from where he sat.

Using recordings of the white-winged potoo, scientists have since found these birds in several other areas in Amazonia and Guianas. Recent studies have also found them in the Atlantic Forest of Brazil. Cohn-Haft believes that, based on size and slight differences in the vocalizations of the Atlantic Forest specimens, that there may be two distinct species of potoo. This is indeed exciting news—not only has the original "lost" species been found, but another unknown species may also have been uncovered as part of the search!

Boating excursions to the Caxiuanã National Forest, which include tours into the backwater areas that contain a diverse array of birds and other wildlife, can now be booked. Watching as nightfall descends, you can see these elusive potoos, too!