Forster's Tern

Forster's tern is a medium-sized tern with a slender body, deeply forked long tail and relatively long legs. In its non-breeding plumage, the crown is white and a black comma-shaped patch covers the eye and the ear-covert. The wings are gray with the primaries being dark silvery gray, while the underside is white. The bill is black and the legs are a dull brownish red. When breeding, an intense black cap extending down the neck appears. The wings and the back are pale gray while the underside is bright white. It has a black-tipped orange bill and bright orange legs. Voice: The common call of the Forster's tern is a descending kerr. The threat call used in defensive attack is a low harsh zaar. A succession of kerrs is used by the female as a begging call during courtship.