Rare bird having blind chicks

By Joe Stenson -

April 1, 2016

ONE of the rarest birds in Scotland is producing chicks with “lethal blindness” as a result of inbreeding.

There are only 60 breeding pairs of red-billed choughs in Scotland – nesting on the remote Hebridean islands of Colonsay and Islay.

The birds are remarkable for their brightly coloured crimson bills and their mischievous acrobatic behaviour.

But new research by the University of Aberdeen – published in the Journal of Animal Ecology – has revealed that newly-hatched birds are being born blind due to inbreeding on the islands.

The study shows that 3% of chough chicks born in Scotland every year since 1998 are now born blind.

29 “nestlings” – young birds that have yet to leave the nest – have been hatched blind by nine pairs of parents since the first case was recorded in 1998.

The chicks are otherwise healthy and survive in the nest when they are fed by their parents.

But once they leave the nest they are unable to care for themselves and die.

As a result the paper refers to their impairment as “lethal blindness”.

And – according to the research – the parent pairs which are hatching blind chicks are even breeding more than their healthy counterparts.

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