How Swans Stay White in Muddy Waters
Wall Street Journal
They use oil from a special gland and their own saliva to keep dirt off their feathers
https://www.wsj.com/articles/how-swans-stay-white-in-muddy-waters-f15e055b
Wall Street Journal
They use oil from a special gland and their own saliva to keep dirt off their feathers
https://www.wsj.com/articles/how-swans-stay-white-in-muddy-waters-f15e055b