A 'Pile' of Tree Swallows
The morning after a freak spring snowstorm, these migrating tree-swallows huddled in a pile to conserve precious energy as they sunned themselves in the freezing temperatures. I've never heard of or seen this behaviour before with any bird. By forming a dense mass like this and sharing body heat, energy is conserved. I think this photo may be one of the only ever taken of this phenomenon, so it might be exceptionally rare, possibly unique. The following photo taken the previous day during the snowstorm has gained international media attention www.flickr.com/photos/keithmwilliams/5727282051/in/photos... Part of a group of several hundred migrating swallows, the photos were taken on the shore of the Yukon River in northern Canada.