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This Bird Is No Airhead: Scientist
Parrots are renowned for their smarts, and now research shows they also have brains to crow about. In fact, relative to body weight these colourful birds have brain sizes that are on par with chimpanzees and orangutans. It's a discovery that could set feathers flying in the movement to limit the use of parrots as pets.
“Humans have these really big brains, but guess what, parrots have really big brains too. In fact, if you overlay a graph of brain size to body mass for parrots on top of one for non-human primates, they sit in a perfect line,” says Dr. Andrew Iwaniuk, an NSERC-sponsored postdoctoral reseacher in the psychology department at the University of Alberta.
The image of the savvy parrot is an ancient one. Australian aboriginal cultures view parrots as wise, wily tricksters in much the same way that ravens are depicted by North American First Nations cultures. Parrots are known to be able to solve complex puzzles and have been taught to famously mimic human speech. However, until now there was no detailed comparative study of bird brains on which to make a link between these cognitive abilities and the bird's brain size and structure.
The parrot-primate grey matter comparison emerges from an exhaustive study of the adult brains of more than 1400 species of birds from around the world. The work, completed as part of Dr. Iwaniuk's Ph.D. at Monash University in Australia, is published in the current issue of the Canadian Journal of Zoology.
The research is the first to empirically verify that the term “bird brain” is a gross generalization. Relative to body weight, birds’ brains have a dramatic range in size. For example, for a parrot and duck of equal weight the parrot’s brain is twice the size of the quacker’s.
But the biggest surprise for Dr. Iwaniuk came when he compared these bird brains with those of mammals. Not only were the Psittaciformes – the parrots, cockatoos and lorikeets – at the top of the avian brain class, but they held their own against what we consider to be the most intelligent animals (excluding ourselves), the non-human primates.
“There are actually parrots that for a given body size have bigger brains than non-human primates,” says Dr. Iwaniuk.
The correlation between brain size and intelligence is a hotly debated one among biologists, particularly because of efforts to link brain size and intelligence to gender and ethnicity in humans. Brain size is probably not a useful standard for judging intelligence among members of a single species. However, biologists generally see a correlation between overall brain size, and specifically the size of the cerebral cortex, and the evolution of cognitive functions in a species.
“Parrots and primates share a wide range of behaviours, including complex social lives, feeding on seasonally fluctuating foods that are difficult to obtain, tool use, long periods of juvenile dependency, long lives and low reproductive rates. Therefore, there does appear to be a lifestyle that predisposes some animal groups to evolve relatively large brains,” Dr. Iwaniuk says.
He notes that the recognition of the relative size of parrots’ brains and the probable link to their impressive mental abilities should get humans thinking about whether captivity is driving Polly crackers.
“I'm hoping that at some point people will understand the implications this may have for people keeping parrots at home,” says Dr. Iwaniuk. “In a lot of areas of Canada no one's allowed to have primates as pets. But anyone can go off the street and buy a Macaw that ends up being psychotic after two years because it’s stuck in a cage the size of a refrigerator.”
Dr. Andrew Iwaniuk
The study “Developmental differences are correlated with relative brain size in birds: a comparative analysis,” published January 12th in the Canadian Journal of Zoology, can be downloaded for free online at http://pubs.nrc-cnrc.gc.ca/cgi-bin/rp/
Dr. Iwaniuk’s parrot-primate research was first presented at the November 2003 meeting of the Society for Neuroscience. An abstract of the presentation can be found by following the links at http://web.sfn.org/.