Climate change may be shrinking tropical birds

Even a subtle decrease in size could help animals stay cooler, researchers suspect

a collared puffbird perched on a human hand

Many tropical birds, such as this collared puffbird (Bucco capensis), are shrinking in size. The change may help the birds stay cool in a warming climate.

V. Jirinec

In a remote corner of Brazil’s Amazon rainforest, researchers have spent decades catching and measuring birds in a large swath of forest unmarred by roads or deforestation. An exemplar of the Amazon’s dazzling diversity, the experimental plot was to act as a baseline that would reveal how habitat fragmentation, from logging or roads, can hollow out rainforests’ wild menagerie.