Great Potoo

## About

A great potoo perched at night with its pupils fully dilated.

The great potoo ***(Nyctibius grandis)*** or the greater potoo is a owl-like species of predator nocturnal bird which occurs in South and Central America. They have greyish brown, tawny and light grey plumage with mottled with areas of dark colours in order to make them resemble a tree limb or woody branch. The plumage also appears very similar in appearance to back, due to its streaked and marbled markings, which resemble wood grooves and barky textures. The tail feathers are elongated with 8-9 lateral white stripes. To convey mimicry, a great potoo will position itself like a branch, outstretching and narrowing its body while squinting its eyes to resemble a lifeless tree limb. Great potoos have very small but very wide hooked beaks, which gives them a wide gape when fully open. The eyes are large and have yellow-brown irises and large black pupils. To aid with photoreception, the great potoo has the ability to independently dilate each individual pupil at will, allowing them to potential maximise incoming light when needed. This ability is particularly useful when spotting possible prey at night. Much of the time, a potoo can be identified by the large amount of eyeshine that the eyes exhibit when exposed to light in a dark environment. Their ability to dilate their pupils individually has given them a reputation for being scary, ridiculous or even ugly in appearance depending on the amount of pupil dilation. Great potoos reach 48-60cm (18.8-23.6in) from head to tail and weigh 360-650g (12.7-22.9oz). The average wingspan of the great potoo is 73.48cm (28.93in) but ranges between 70-80.4cm (27-31.7in). It is the largest of the seven potoo species.

## Diet

The great potoo is a carnivorous predator bird, preying on large flying invertebrates such as insects like katydids. Potoos also eat small birds. After capturing prey, a great potoo will fly back to the perch it was sitting on before attacking, to eat its catch. Prey is typically caught in the air, the potoo using its wide maw to engulf its prey, similarly to a pelican ***(Pelicanus)***. Their hunting perches are usually not far from their daytime roosting spot and are a part of a larger territory.

## Conservation Status

Great potoos are classed as least concern by the IUCN and have no real immediate threats which can be noted as particularly dangerous to the species.

## Range and Population

The great potoo can be found in dense neotropical rainforests and woodlands throughout South and Central America. They occur in a wide range stretching from as far south as southeast Brazil and as far north as southeast Mexico. They appear to be uncommon in areas of low forest coverage forest outskirts, though they have been known to inhabit areas near farmland, suggesting some adaptability. Great potoos are decreasing in numbers, though not rapidly and are suspected to have a massive population between 500,000-4999,999 mature individuals.

## Behaviour

As great potoos are nocturnal, they are mostly active at night. During the day they are almost entirely sedentary, perching stiffly on trees or stumps and mimicking tree limbs by outstretching their bodies, narrowing their feathers and squinting or closing their eyes. They do this as a form of camouflage as to avoid predation from primates, hawks and tayras ***(Eira barbara)***. When threatened in this state, the great potoo will completely freeze in an attempt to make its facade more convincing as to deter the threat. When a great potoo has its eyes closed, it can still sense predators through the use of a specialised eyelid slit. This allows them to realise when a threat is approaching even when sleeping. At night the great potoo emanates a few very characteristic calls, the most common being a croaking "baaooo" and a more frequent, lower and raspy "whoooaaap". These calls are hypothesised to establish territory boundaries between individuals, while a third more uncommon clicking call's purpose is unknown. The former two calls have earnt the species the colloquially popular name "ghost bird", due to their eerie and haunting nature. Great potoos mate in the approximate wet season of their respective range and a breeding pair will nest in the deep notch of a selected roosting tree, laying just one egg. Little is known about incubation, though fledging is known to occur around 55 days from hatching. Great potoos are monogamous and pairs will tend to the chick collaboratively, though both potoos have never been seen at their nest at the same time during the day. After two weeks the chick will develop all of its mature plumage and in the next five weeks, the chick will reach 2/3 of their adult size. Following one month, the chick will begin to explore its roosting tree and its parents will only interact with it after dark, presumably to feed it. The chick will finally leave its roost permanently after just under two months, only returning occasionally only at night.

### Relationship with Humans

The great potoo may be threatened by human-caused land clearing. The potoo has however, seen popularity in online spaces for its odd appearance and unique features among birds.

## In Captivity

Very few zoos exhibit great potoos due to their uncommon nature and specific lifestyles.

## Sources

* IUCN Red List of Threatened Species - https://www.iucnredlist.org/species/22689636/163599353
* Great Potoo | Wikipedia - https://en.wikipedia.org/wiki/Great\_potoo
* Great Potoo | Animal Diversity Web, University of Michigan Museum of Zoology - https://animaldiversity.org/accounts/Nyctibius\_grandis/
* Great Potoo | eBird - https://ebird.org/species/grepot1
* What is a Great Potoo? | Science Focus - https://www.sciencefocus.com/nature/what-is-a-great-potoo
* Great Potoo | ZOOINSTITUTES - https://zooinstitutes.com/animals/great-potoo-5103/