Kiwi colour-blind, gene study finds - NZ Herald

Mutations in genome from about 35 million years ago point to vision changes but also strong sense of smell.
Not only is our quirky national bird flightless - it's also colour blind.
The finding comes from new research revealing how the endangered kiwi evolved its sense of smell and colour 35 million years ago to help it cope with its nocturnal life sniffing around the undergrowth at night.
The study published in the journal Genome Biology mapped, for the first time, the genome of the North Island brown kiwi - the most common species of the endangered bird.
After sequencing the genome of two kiwi, the German scientists who led the study uncovered evolutionary changes that could help explain why it was among the 3 per cent of bird species that have adapted to nocturnality.
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"We've seen for the first time that kiwi lack colour vision, and that their olfactory receptors can probably detect a larger range of odours which may be essential for their night-time foraging," said study lead author Diana Le Duc, of the University of Leipzig. "These adaptations seem to have happened around 35 million years ago, soon after their arrival in New Zealand, probably as a consequence of their nocturnal lifestyle."
The gene responsible for black and white vision, rhodopsin, was found to be similar in other vertebrates.
However, the team identified mutations in the green and blue vision receptor genes, which could render blue and green colour vision absent in the kiwi.
The changes in kiwi vision and smell were consistent with changes thought to occur during adaptation to nocturnal lifestyle in mammals.