A "Skimming" Black Skimmer

© duncantakeru

One look at a Black Skimmer's bill and you know it's a very special bird—tern, in fact. The lower mandible is over an inch longer than the upper. Why? As it flies, the Black Skimmer drops this knife-thin appendage into the water. Once it hits a fish – snap – the hinged upper mandible quickly closes shut. This tactile form of feeding allows skimmers to hunt for fish at all times of day, even at night. Interestingly, skimmers are the only known bird with vertical "cat-like" pupils, an adaptation that protects the eye from harsh sunlight over water and sand.

Watch a video of a skimmer close-up.

Listen to the BirdNote show Why the Black Skimmer Skims.

Do you want to see how thin this bill is? Check out the cover of our 2011 Annual Report.