Great potoo

Great potoo
Great potoo
 Birdsong 
Conservation status

Least Concern  (IUCN 3.1)[1]
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Aves
(unranked): Cypselomorphae
Order: Caprimulgiformes
Family: Nyctibiidae
Genus: Nyctibius
Species: N. grandis
Binomial name
Nyctibius grandis
(Gmelin, 1789)

The great potoo (Nyctibius grandis) is a bird, both the largest potoo species and the largest member of the order Caprimulgiformes (nightjars and allies). It occurs in tropical America.

Description

Though related to the nightjars, like other potoos it lacks the bristles around the mouth found in the true nightjars (Caprimulgidae). The great potoo is larger than a crow at 48–60 cm (19-24 inches) tall and 360-650 grams (12.7 oz-1.4 lb). Wingspan in these bird is typically around 70 to 80.4 cm (27.6 to 31.7 in), though larger specimens can attain 100 cm (39 in).[2][3] Among standard measurements, the wing chord is 34.2 to 40 cm (13.5 to 15.7 in), the tail is 22 to 29.5 cm (8.7 to 11.6 in), the bill is 1.6 to 2.2 cm (0.63 to 0.87 in) and the tarsus is 2.6 to 3.7 cm (1.0 to 1.5 in).[4] This potoo's size is distinctive when it is seen. It is pale greyish to brown, finely patterned with black and buff. It has large orange eyes. The overall appearance is pale and grayish. The underside is barred and vermiculated, including the buffy chest. The tail is barred with sharply defined black borders, while the head and back are mottled with gray and buff. Like most members of their order, the great potoo has plumage that is well-suited for camouflage.

The song is described as deep, guttural, strangled cries like borrrrrr or oorrroo repeated after a consistent interval of 10 to 20 seconds. The most common call is a loud, startling bark, BWOW! or GWOK! This call is usually made while the bird is disturbed.

stuffed specimen

Range

It ranges from southern Mexico through northeastern Guatemala and through most of Central America down through South America as far as Bolivia and southeastern Brazil.

Habitat

The great potoo is found mostly in dense lowland forest, forest edges and clearings. It may also range into foothills (up to about 1,500 m elevation), second-growth, open woodlands (including plantations) and is sometimes seen around meadows, but they always require trees-etc., for their camouflaged imitative perch.

Ecology

This nocturnal predator is usually seen perched high above the ground while forgaging, sallying out when prey is spotted. After the pounce, the potoo almost always returns to its previous perch. The prey consists mostly of large flying insects, especially large beetles, katydids and Orthoptera (including crickets and grasshoppers). Bats are also taken. This species uses the sit and wait method where it will sit on an exposed perch waiting for a prey item to fly by then will dart out and return to the branch with it. Very often birds of this species will use the same hunting perch nightly.[5] Normally, during the day it perches upright on a tree stump, and is overlooked because it resembles part of the stump; this is a camouflage, not just by coloration, but a camouflage by the setting. The great potoo can be located at night by the reflection of light from its eyes as it sits vertical on a post, roost, or angled-tree trunk.

Breeding has been recorded as typically February to August, but depending on the portion of this bird's range breeding birds can be met with almost year-round.[6] The nest is a slight depression on a thick tree branch,[7] at least 10 m (33 ft) above ground, with a single white (slightly spotted) egg measuring about 5.2 x 3.8 cm (2 x 1.8 inches). Few details are known of the brooding behavior, but about a month elapses before the offspring is seen alone at the nest. A chick of a few days old weighed 220 g (7.8 oz).[2] After about 5 weeks the nestling is a two-thirds version of the adult, but with a lighter build, paler plumage, shorter tail, and smaller bill with less rectal bristles. The fledging period must be at least 2 months. After this time span, the offspring do not return to the nest site.[2]

Although the adult potoo likely has few natural predators, predation of eggs, nestlings and fledging is apparently not uncommon. Adults stay near the nest throughout the day and rely upon camouflage to protect their offspring. Predators of great potoo nests in Costa Rica have included monkeys such as mantled howlers, Geoffroy's spider monkeys and white-headed capuchins as well as tayras and collared forest falcons.[8]

Status

The great potoo is normally described as "uncommon", but occurs frequently in areas of less disturbed forests and is often found to be rare along the edges of its range. The clearing of forest is the only conservation threat known to this bird. Due to its large range, it is considered a species of least concern by the IUCN.

References

  1. ↑ BirdLife International (2012). "Nyctibius grandis". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
  2. ↑ 2.0 2.1 2.2 Haverschmidt, F. 1948. Observations on Nyctibius grandis in Surinam. The Auk, 65: 30-33.
  3. ↑ "Great Potoo: Truths and Legends | Caiman English". En.caiman.com.br. 2010-12-06. Retrieved 2012-08-25.
  4. ↑ Holyoak, D.T. (2001): Nightjars and their Allies: the Caprimulgiformes. Oxford University Press, Oxford, New York. ISBN 0-19-854987-3.
  5. ↑ Cohn-Haft, M. 1999. Family Nyctibiidae (Potoos). Pages 288-301 in J. del Hoyo, A. Elliott, and J. Sargatal (editors), 'Handbook of the birds of the world. Volume 5. Barn-owls to Hummingbirds'. Lynx Edicions, Barcelona, Spain.
  6. ↑ E.g. an attended nest at Tiputini Biodiversity Station, Ecuador, in late December 1999 (Cisneros-Heredia 2006).
  7. ↑ E.g. Ceiba sp. (Cisneros-Heredia 2006)
  8. ↑ Young, B., J. Zook. 1999. Nesting of four poorly-known bird species on the Caribbean slope of Costa Rica. The Wilson Bulletin, 111: 124-128.

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