Thank you for sharing, Sally! What a unique shot of this magnificent bird!
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. Their lower mandible skims or slices over the water's surface ready to snap shut any small fish unable to dart clear.
The skimmers are sometimes included within the gull family Laridae but separated in other treatments which consider them as a sister group of the terns.
The Black Skimmer has an additional adaptation and is the only species of bird known to have slit-shaped pupils. Their bills fall within their field of binocular vision and enable them to carefully position their bill and capture prey. They are agile in flight and gather in large flocks along rivers and coastal sand banks. source