Potok, poor-me-one ( Nyctibius griseus ) - The master of camouflage
Potok, poor-me-one ( Nyctibius griseus ) - The master of camouflage
Potok, poor-me-one ( Nyctibius griseus ) - The master of camouflage
Potoos (family Nyctibiidae) are a group of near passerine birds related to the nightjars and frogmouths. They are sometimes called poor-me-ones, after their haunting calls. There are seven species in one genus, Nyctibius, in tropical Central and South America.
These are nocturnal insectivores which lack the bristles around the mouth found in the true nightjars. They hunt from a perch like a shrike or flycatcher. During the day they perch upright on tree stumps, camouflaged to look like part of the stump. The single spotted egg is laid directly on the top of a stump.
Behavior
Common potoo camouflaged on a stump
The potoos are highly nocturnal and generally do not fly during the day. They spend the day perched on branches with the eyes half closed. With their cryptic plumage they resemble stumps, and should they detect potential danger they adopt a "freeze" position which even more closely resembles a broken branch.[6][7] The transition between perching and the freeze position is gradual and hardly perceptible to the observer.
The English zoologist Hugh Cott, describing Nyctibius griseus as "this wonderful bird", writes that it "habitually selects the top of an upright stump as a receptacle for its egg, which usually occupies a small hollow just, and only just, large enough to contain it ... the stump selected had thrown up a new leader just below the point of fracture ... and the birds sat facing this in such a way that when viewed from behind they came into line and blended with the grey stem."[8]
Diet and feeding[edit]
Potoos feed at dusk and at night on flying insects.[3] Their typical foraging technique is to perch on a branch and occasionally fly out in the manner of a flycatcher in order to snatch a passing insect. They occasionally fly to vegetation to glean an insect off it before returning to their perch, but they do not attempt to obtain prey from the ground. Beetles form a large part of their diet, but they also take moths, grasshoppers and termites. One northern potoo was found with a small bird in its stomach as well. Having caught an insect, potoos swallow it whole without beating or crushing it.
Breeding
Potoos are monogamous breeders and both parents share responsibilities for incubating the egg and raising the chick. The family does not construct a nest of any kind, instead laying the single egg on a depression in a branch or at the top of a rotten stump. The egg is white with purple-brown spots. One parent, often the male, incubates the egg during the day, then the duties are shared during the night. Changeovers to relieve incubating parents and feed chicks are infrequent to minimise attention to the nest, as potoos are entirely reliant on camouflage to protect themselves and their nesting site from predators. The chick hatches about one month after laying and the nestling phase is two months, a considerable length of time for a landbird. The plumage of nestling potoos is white and once they are too large to hide under their parents they adopt the same freeze position as their parents, resembling clumps of fungus.
Defence
Mobbing behavior has also been observed among common potoos (Nyctibius griseus). Avian mobbing is a widespread behavior in which an individual or a group of birds deliberately confronts a potential predator. Mobbing birds crowd around the predator, approaching and retreating, sometimes even chasing and attacking the predator. They also emit loud repeated calls, which generally attract additional birds of other species to join the mobbing.
The behaviors described above, suggest that common potoos adopt different defensive strategies depending upon circumstances. For a lone potoo, or brooding adult with an active predator close to the nest, the best course to avoid detection is to remain motionless and rely on camouflage. In the case of more distant, localized threat, however, the risks resulting from very gradual movement by an adult are exceeded by the less cryptic nesting. Nocturnal predators rely less on vision for locating prey therefore a different strategy may be required at night.
Source: en.wikipedia.o...
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