A new species of owl has been discovered in the rainforests of a tropical island off the coast of Africa.
The bird, called the Principe Scops-Owl, was found on Príncipe, which lies off the west coast of Africa in the Gulf of Guinea.
Scientists first found it in 2016, although suspicions of its occurrence gained traction back in 1998, and testimonies from local people suggesting it exists could be traced back as far as 1928.
Its Latin name is Otus bikegila, Otus being the generic name given to a group of small owls sharing a common history, commonly called scops-owls.
They can be found throughout Europe, Asia and Africa and include common species as the Eurasian Scops-Owl (Otus scops) and the African Scops-Owl (Otus senegalensis).
Lead study author Martim Melo said: “The discovery of a new bird species is always an occasion to celebrate and an opportunity to reach out to the general public on the subject of biodiversity.
“In this age of human-driven extinction, a major global effort should be undertaken to document what may soon not be anymore.”
The scientists behind the discovery said “bikegila” was chosen in homage of Ceciliano do Bom Jesus, nicknamed Bikegila - a former parrot harvester from Príncipe Island and now a ranger of its natural park.
The researchers said: “The discovery of the Principe Scops-Owl was only possible thanks to the local knowledge shared by Bikegila and by his unflinching efforts to solve this long-time mystery.
“As such, the name is also meant as an acknowledgment to all locally-based field assistants who are crucial in advancing the knowledge on the biodiversity of the world.”
Its unique call, a short “tuu” note repeated at around one note per second, was one of the main clues that led to its discovery.
It is often bleated out in duets when just after the night has fallen.
The entire island of Principe was extensively surveyed by scientists to work out how many owls there were, and where they could be found.
It turned out they could only be found in one rainforest in the south of the island.
Its habitat has a radius of about 15 square kilometres, and the birds preferred to stay in the lower parts of trees.
Despite their habitat only being four times the size of Central Park in New York, between 1,000 and 1,500 of them are packed into it.
However, because they live in such a small area, the researchers said they should be classified as critically endangered.
They are also calling for this classification because their habitat is near a hydroelectric dam that's currently being built.
Monitoring the population will be essential to get more precise estimates of its size and follow its trends.
The species is the eighth type of bird commonly found on the island to be discovered, even though Principe is only 139 square kilometres.
The researchers added: “The discovery of a new species - that is immediately evaluated as highly threatened - illustrates well the current biodiversity predicament.
“On a positive note, the area of occurrence of the Principe Scops-Owl is fully included within the Príncipe Obô Natural Park, which will hopefully help secure its protection.
“Although it may seem odd for a bird species to remain undiscovered for science for so long on such a small island, this is by no means an isolated case when it comes to owls.
“For example, the Anjouan Scops-Owl was rediscovered in 1992, 106 years after its last observation, on Anjouan Island (also known as Ndzuani) in the Comoro Archipelago, and the Flores Scops-Owl was rediscovered in 1994, 98 years after the previous report.”
The findings were published in the journal ZooKeys.
