Nature
PUBLISHED
Australia is one of only two places in the world to have a nocturnal parrot. The feature is so distinctive that Pezoporus occidentalis's common name is the "night parrot", but the bird seems to be a refutation of the idea of Intelligent Design (or confirmation Australia's fauna has been doing its own thing for millennia) as a new study has revealed its night vision is probably terrible.
The rest of this article is behind a paywall. Please sign in or subscribe to access the full content.The night parrot's unusual lifestyle has attracted great interest from ornithologists, but it remains a mystery. The bird is among the rarest species on Earth, estimated to have somewhere between 50 and 250 survivors. The few recorded sightings are scattered over a vast area of inland Australia, making it hard to know where to seek the birds – among the limited photographs some have been disputed as fake. There were no confirmed sitings for 67 years, during which time extinction was widely suspected.
All this makes the night parrot extraordinarily difficult to study, including for those seeking to save it. “You have to watch from a distance, rather than doing experiments,” Dr Vera Weisbecker of Flinders University told IFLScience, because each individual is too precious to risk. Watching from a distance is particularly challenging for a species that is so rare and only comes out at night.
Nevertheless, Weisbecker has been able to expand our knowledge by having the only intact specimen of a night parrot's skull scanned to make a 3D reconstruction. In Scientific Reports, she reveals the parrot has average-sized eyes, even for a bird its size, instead of developing large ones to catch every available photon like most nocturnal creatures.
Nor is it just about the eyes. "We found that the Night Parrot has similar eye size to other parrots, with smaller optic nerves. It also has smaller optic lobes, which are visual processing areas in the brain," co-author Aubrey Keirnan explained.
Yet as Wesibecker noted, "Night Parrots must be able to find their way at night – to find food, avoid obstacles while flying, and escape predators.”
Weisbecker told IFLScience she doesn't know if the parrot has compensated by having better hearing or smell, but she did point out that some nocturnal animals find vision so difficult they largely abandon it and develop their other senses. She does, however, think night parrots are good at telling light from dark, even though they must struggle to detect small objects.
The findings are important for the birds' conservation since the fences that protect night parrot territory from foxes and cats could also be lethal if not seen in the dark. Weisbecker suggests removing unnecessary fences from their habitat, and putting tags on those that need to stay.
Unraveling the night parrot's evolutionary path to reach this improbable state is difficult because it has only one close relative, the Western ground parrot. Stranger still, Wisbecker told IFLScience, the ground parrot actually has larger eyes and optic nerves than the night parrot, despite being active in daylight.
