A study of 250 species of Himalayan songbirds has revealed how their feathers evolved for higher altitudes. The study found birds living in colder, more elevated environments had feathers with more fluffy down - providing them with thicker "jackets," according to BBC. The insight reveals how feathers provide the tiniest birds with such efficient protection from extreme cold. It also provides clues about which species are most at risk from climate change, the scientists say. The findings were published in the journal Ecography.
The study was inspired by a tiny bird lead researcher Dr. Sahas Barve saw during an icy day of fieldwork in the Himalayas, in 2014.
"It was -10C. And there was this little bird, a goldcrest, which weighs about the same as a teaspoon of sugar. It was just zipping around catching bugs," said the researcher from the Smithsonian National Museum of Natural History in Washington DC.
Barve's fingers went numb as he tried to take notes. But he remembers being blown away by the little goldcrest.
"To survive, this bird has to keep its heart at about 40C. So it has to maintain a difference of 50C in that little space," he said.
"I was like, 'OK, I really need to understand how feathers work," he noted.
Fortunately, Barve's home institution has one of the largest bird collections in the world. Examining the feathers of nearly 2,000 individual birds, in microscopic detail, he noticed a pattern linked their structure to their habitat.
