Bufflehead

I saw a duck called a bufflehead at the Salton Sea SRA a few weeks ago and had no idea what it was. The when I learned its name, I'd never heard of it before. 

I saw a male, the most interesting of the species. It puffs out the feathers on its head greatly increasing the size. It gets its name from the oddly shaped and large head - buffalo head or bufflehead. Adult males are black and white with a large white patch behind the eye and an iridescent green and purple head. 

It is one of the smallest American ducks and is highly active, almost continually diving.