NEW ZEALAND: Picking kiwis' brains

Kiwis - they gave their name to a furry fruit, now they are giving their brains to science. University of Auckland researchers are examining the flightless bird's brain with magnetic resonance imaging technology for a study they hope will help save New Zealand's national icon from extinction.

Using frozen brains or skulls, PhD candidate Jeremy Corfield and his colleagues use MRI to create 3D images to pinpoint behavioural differences that could be useful in conservation efforts. They are focusing on the size and structure of brain areas with known functions such as vision, auditory, tactile, olfactory, memory and intelligence.

"Enlargements to an area indicate that this system is well developed and crucial for the animal's survival, whereas reductions to an area suggests that this particular system is not well developed and thus not relied upon by the animal," Corfield says.

"With the kiwi we found that visual areas were very reduced whereas tactile, olfaction and auditory areas were large and well developed. This suggested that kiwis have not followed the usual evolutionary route of nocturnal birds, instead developing behavioural strategies similar to small nocturnal mammals.

"In kiwis we also see a massively enlarged forebrain, an area involved in complex processing. An enlargement in this area such as we see in kiwis is thought to mean that this animal has a high level of intelligence."

Corfield says the Auckland project is the first to use MRI techniques to visualise and reconstruct the brain of a rare and endangered species and notes that few studies have used the technology to study the brains of animals.

Kiwis are endangered because of predation by introduced animals such as stoats and cats. Only one in 20 kiwi chicks survives its first year and the population of kiwi in the wild is falling by about 6% a year. Corfield says his research could provide insights into kiwi behaviour that could then be used to develop better conservation methods.

He says the technique could be applied to thousands of other rare and endangered species which are difficult to study using traditional approaches.

Corfield has also used it with two species of the extinct moa - a huge, flightless bird once common throughout New Zealand - finding their brains similar to those of the emu and ostrich, with a well developed visual system and a small olfactory system.

* John Gerritsen is editor of NZ Education Review.