Sternidae

Sternidae is a family of seabirds that includes the terns and skimmers. Terns are typically medium-sized, with long, slender wings, forked tails, and sharp, pointed bills. They are found worldwide, often near coasts, but also inland on lakes and rivers. Many tern species are migratory, traveling long distances between breeding and non-breeding grounds. They are known for their graceful flight and distinctive plunge-diving hunting technique, where they hover over the water before diving headfirst to catch fish.

Skimmers are a distinct group within Sternidae, characterized by their unusually long, serrated lower mandible. This unique bill is used to "skim" the surface of the water while flying, catching small fish and crustaceans. There are only three species of skimmers, found in North and South America and Eurasia. They tend to nest in colonies, often on sandy beaches or islands.

The family Sternidae is part of the order Charadriiformes, which also includes gulls, auks, and shorebirds. While closely related to gulls, terns are generally more slender and have a more aerial lifestyle. Conservation concerns exist for some Sternidae species due to habitat loss, pollution, and overfishing.