Common potoo - WikiHQ

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The common potoo, or kakuy (Nyctibius griseus), or urutau is one of seven species of birds within the genus Nyctibius. It is notable for its large, yellow eyes and a wide mouth. Potoos are nocturnal and are related to nightjars and frogmouths. They lack the characteristic bristles around the mouths of true nightjars.

Taxonomy

The common potoo was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with all the nightjar-like species in the genus Caprimulgus and coined the binomial name Caprimulgus griseus. Gmelin based his description on "L'engoulevent gris" from Cayenne that had been described from a preserved specimen in 1779 by the French polymath Georges-Louis Leclerc, Comte de Buffon. The common potoo is now one of the seven potoos placed in the genus Nyctibius that was introduced in 1816 by the French ornithologist Louis Pierre Vieillot. The genus name is from the Ancient Greek nuktibios meaning "night-feeding", from nux night and bios "life". The specific epithet griseus is Medieval Latin meaning "grey".

The common potoo was formerly considered to be conspecific with the northern potoo (Nyctibius jamaicensis). The species were split by the American Ornithologists' Union in 1995 based mainly on the differences in vocalization.

Two subspecies are recognised: This disruptive coloration allows the potoo to camouflage into branches. The eyes can appear as giant black dots with a small yellow ring, or as giant yellow irises with small pupils due to voluntary pupil constriction.

It has a haunting melancholic song, a BO-OU, BO-ou, bo-ou, bo-ou, bo-ou, bo-ou, bo-ou, bo-ou dropping in both pitch and volume. When seized, this bird produces a squeaky sound not unlike that of a crow. This call greatly differs from that of much deeper and more dramatic northern potoo.

Distribution and habitat

The nominate subspecies of the common potoo is found in Trinidad and Tobago and every mainland South American country except Chile, though it has been recorded in that country as a vagrant. There it ranges from the Andes to the Atlantic Ocean. N. g. panamensis is found from eastern Nicaragua south through Costa Rica and Panama and west of the Andes from northwestern Venezuela through Colombia and Ecuador into northwestern Peru.

The common potoo is a resident breeder in open woodlands and savannah. It avoids cooler montane regions; it is rarely observed over above mean sea level even in the hottest parts of its range. It tends to avoid arid regions but was recorded in the dry Caribbean plain of Colombia in April 1999. It has many populations in the gallery forest-type environment around the Uruguayan-Brazilian border. A bit further south, where the amount of wood-versus grassland is somewhat lower, it is decidedly rare, and due west, in the Entre Ríos Province of Argentina with its abundant riparian forest, it is likewise not common. The birds at the southern end of their range may migrate short distances northwards in winter.

Behavior and ecology

right|thumb|A common potoo masquerading as a branch

Cryptic behavior

The common potoo seeks to mimic the perch on which it rests, using a technique called masquerading. Adult and juvenile potoos choose perches that are similar in diameter to their own bodies so that they can better blend in with the stump. Most potoos choose stumps and other natural materials on which to rest, but some adults have been spotted perching on human-made items. These birds adjust their perching angle to best mimic the stump where they are. If disturbed by a human being, its behaviors can be quite variable - quickly flying away, intimidation via beak-opening, or remaining still even when being touched.

Feeding

This nocturnal insectivore hunts from a perch like a shrike or flycatcher. It uses its wide mouth to capture insects such as flies and moths, but also ants, other hymenopterans, termites, grasshoppers, locusts, and crickets. It normally chooses a branch stump as a nest and adds no sort of decorative or insulative material. It ejects feces from its perch to keep the nest clean.

thumb|Adult and juvenile common potoos in alert posture

Common potoos are monogamous. After mating, the female lays a single white egg with lilac spots directly into the depression in a tree limb. Apart from flying away, chicks respond to disturbances in a similar manner to adults.

External links

Common potoo videos, photos & sounds on the Internet Bird Collection
"Common potoo" photo gallery VIREO