The skimmers, Rynchopidae, are a small family of tern-like birds in the order Charadriiformes, which also includes the waders, gulls and auks. The family comprises three species found in South Asia, Africa, and the Americas. The three species are the only birds with distinctive uneven bills with the lower mandible longer than the upper. This remarkable adaptation allows them to fish in a unique way, flying low and fast over streams.