Birds shrink to stay cool

Some species of Australian birds are shrinking and the trend is likely to continue because of global warming, a scientist warns.

Janet Gardner, an Australian National University biologist, led a team who measured museum specimens to plot the decline in size of eight species of Australian birds over the past century.

The findings, in the British journal Proceedings of the Royal Society B: Biological Sciences, say the birds in the southeast became 2 to 4 per cent smaller. Over the same century, the average daily temperature rose 0.7C. The research concluded the birds were downsizing because smaller bodies shed heat faster than larger ones.

Other studies have found similar trends in Britain, Denmark, Israel and New Zealand.