Science & Technology: Under the Microscope: Birds take a hop up the evolutionary scale

BIRDS AREN'T really birdbrained. In fact, neurobiologists now believe that avian intelligence is on a par with the intellectual ability of mammals.

A team of 26 neuroscientists have proposed changes to the scientific terminology used for decades to describe the brain structure of birds. They want to rid it of what they consider are outdated and irrelevant descriptions that downgrade the true scale of avian brainpower.

Traditionally, birds have been viewed as lower than mammals in terms of the evolutionary development of intelligence. This is reflected in the formal descriptions given to the so-called "primitive" regions of a bird's brain.

However, in a revisionist article in Nature Reviews Neuroscience, the scientists argue that these regions of a bird's brain carry out highly sophisticated processing of sensory information as well as controlling the complex muscle movements associated with flight. These parts of the bird's brain are just as equal to the analogous regions of the "higher" mammalian brain, the scientists say.

Erich Jarvis of Duke University, one of the authors, says the view that avian evolution is somehow more primitive than mammalian in terms of intelligence is out of date. The new nomenclature, he says, will put birds alongside rather than below mammals in terms of brain evolution. "Current understanding of the avian brain requires a new terminology that better reflects these functions and the homologies between avian and mammalian brains," Jarvis says. "There is a strong interest across neuroscience in using birds as models for learning and development, and migratory and social behaviour," he says.

The new nomenclature for avian brains replaces a system developed in the 19th century, which was a mix of Darwinian and Aristotelian theories that saw evolution as a progressive transition from lower to higher intelligence.