Nyctibius grandis
great potoo

Great potoos are neotropical birds found throughout Central America from as far north as southern Mexico to as far south as Bolivia. (Grzmek, 2002; Rangel-Salazar and Vega-Rivera, 1989)

Great potoos live primarily in forests and rainforests but have also been found in forest edge habitat and on and around farmlands. During they day they are usually found either perched or nesting at least 12 m above ground level in larger trees, usually on branches that are approximately 20 to 30 cm in diameter. At night they may move to lower perches, as low as 1.5 m above the ground, from which they hunt. (Grzmek, 2002; Haverschmidt, 1948; Vanderwerf, 1988)

Great potoos have relatively large heads in relation to their bodies. They have large eyes with a light brown to yellow iris and beaks that are short but broad, giving them a very large gape. In comparison to other Caprimulgiformes, the facial bristles are diminished to non-existent. They have elliptical wings with an elongate tail that aides in steering during noiseless landings on tree branches. The plumage is white to grayish with marbled black and burgundy tones. Tail coloration matches that of the body, with the exception of the 8 or 9 white bars that extend laterally across it. (Borerro, 1974; Grzmek, 2002; Land and Schultz, 1963)

Great potoos are monogamous breeders with no dimorphism between the sexes. In fact, the sexes are so similar that time budgeting at the nest per sex has not been determined. (Vanderwerf, 1988)

Nesting season in great potoos has been observed from June through August in Venezuela and November in Surinam (these are each the approximate wet seasons for those areas). Only one egg is laid per clutch, and little is known of the incubation period. Great potoos do not build nests, rather nests are simply deeper notches in larger branches of their roosting trees. Hatching in great potoos has not been well documented but only one parent is present at the nest per incubation. Weight at hatching is also questionable with the youngest observed nestling mortality weighing 220g. Time to fledging has been determined to be 55 days after hatching. Chicks develop quickly with body feathers appearing through down feathers approximately two weeks after hatching. Five weeks after hatching chicks are almost 2/3 the length of the parents. Chicks begin leaving the nest and investigating the nesting branch one month after hatching. After a month and a half adults no longer return during the day to tend to young. Instead the only interactions between parent and offspring are after dark, which probably includes feeding behavior. At just under two months offspring have usually left the nest without returning to roost during the day. (Haverschmidt, 1948; Vanderwerf, 1988)

Both male and female great potoos incubate eggs at the nest during the day. During incubation it has been noted that at no point were both parents simultaneously at or around the nest. After the eggs have hatched both parents hunt at night and return to the nest to provision young with prey items. Provisioning continues until offspring have fully fledged and permanently leave the nest. (Young and Zook, 1999)

Because of the elusive nature of great potoos, little is known about their longevity and life span. The only documented mortalities were of unknown causes and in one instance a person had shot an adult from a tree. (Haverschmidt, 1948)

Great potoos are a solitary species with the only observed social interactions being between parents and young during parental care and provisioning. Great potoos are nocturnal, with a majority of their activity at night focused on catching and consuming prey items including large flying insects and sometimes bats. Feeding includes sallying flights from lower perches then returning to the perch to consume prey items. Prey is usually caught from the air by engulfing it in their large gape. During the day they are extremely still, and usually find a higher perch if they are not in their nesting spot. They avoid movement presumably to enhance the effectiveness of their cryptic coloration. During nesting they reduce their movement to a minimum unless disturbed by possible threats, after which they freeze which is assumed to be predation vigilance. Grooming behavior is distinct in that great potoos scratches their heads by moving the foot up and over the wing instead of coming up from beneath the wing. (Grzmek, 2002; Haverschmidt, 1948)

Great potoos only ever venture away from their roosting area when they hunt. Their hunting perches are usually in close proximity to their day time roosts. The size of these home ranges is not known. (Haverschmidt, 1948)

Vocalizations in great potoos take place mostly at night and are assumed to be a way of communicating territorial boundaries to other great potoos. The repertoire of vocalizations includes a deeper, frog-like "baaaao" and an eerier "whoap". Between the two different calls the "whoap" occurs more often, and has been heard from both birds that are perched and in flight. In rare instances clicking noises have been heard, but their purpose is unknown. (Slud, 1979)

Great potoos are carnivores that hunt nocturnal, flying prey items in the air at night, most frequently large insects and sometimes bats. They usually find a lower perch to fly from and then return to the perch to consume the prey item. (Grzmek, 2002; Haverschmidt, 1948)

Great potoos are relatively large birds with highly cryptic coloration. During the day great potoos remain relatively motionless, and upon disturbance completely freeze in increase vigilance. The known predators of great potoos include monkeys (Cebus, Ateles geoffroyi, and Alouatta palliata), tayras (Eira barbara), and collared forest falcons (Micrastur semitorquatus). Parents are present at the nest during the day and use their cryptic coloration to camouflage the nesting hole. (Young and Zook, 1999)

Great potoos are a predatory species that prey on larger flying invertebrates and in some cases vertebrates, like smaller birds or bats. (Grzmek, 2002)

Great potoos are of no real economic importance to humans, although they play an important role in their native ecosystems.

There are no adverse effects of great potoos on humans.

Currently great potoos are not of primary conservation concern. They inhabit a broad geographic region and are capable of long distance dispersal. It is suspected that the population has been drastically decreased with the reduction in forest area associated with slash and burn farming, but remaining populations are estimated to be large. (Grzmek, 2002)