New Zealand's kiwis may be losing eyesight

Abstract

Blind kiwis seem able to survive quite happily using other senses. It's possible that the flightless birds are evolving to lose their sight--so vision might actually be a waste of energy for them. The discovery of the blind birds came when researchers studied a group of 160 endangered Okarito brown kiwis in the Okarito forest on New Zealand's South Island. We found a very high prevalence of birds with eye lesions, says Alan Tennyson at the Museum of New Zealand Te Papa Tongarewa in Wellington. A third of them had eye problems. But the biggest surprise was chancing upon three sightless birds. No other birds are known to have a free-living population of blind [individuals], says Tennyson.