Sunday 15 September 2019

Owl at full moon: Feathers force prey to freeze

Colour code: Barn owl feathers can determine how successful the bird of prey will be when they are hunting in bright moonlight. Photo: Alexandre Roulin/PA Wire
Colour code: Barn owl feathers can determine how successful the bird of prey will be when they are hunting in bright moonlight. Photo: Alexandre Roulin/PA Wire

Nina Massey

Taxidermy owls on a zip wire have helped determine why white barn owls can be more successful at startling their prey.

Under a full moon the birds' plumage triggers their prey to freeze for a longer time, making it easier to catch, research suggests.

Moonlight changes the activity of animals, altering the way they spot food and stay hidden.

In the study published in 'Nature Ecology & Evolution', scientists used GPS trackers to monitor the hunting success of red and white barn owls under different phases of the moon.

Alexandre Roulin and Luis San Jose from the University of Lausanne, Switzerland, found white owls were more easily seen by their prey on moonlit nights.

However, they discovered that, despite this, they were more successful than the reddest owls, which could remain camouflaged.

Taxidermy owls were on a zip wire to measure the response of voles, the barn owl's main prey.

Light reflected off the white birds' feathers, exploiting the voles' natural aversion to bright light. The prey froze, so the owls could capture them more easily.

However, white owls are only favoured in brighter conditions. When there isn't a full moon, the white plumage allows them to be detected by harassing competitors, such as crows.

Irish Independent

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