Sooty tern

The sooty tern (Onychoprion fuscatus) is a seabird in the family Laridae. It is a bird of the tropical oceans, breeding on islands throughout the equatorial zone. The sooty tern was described by Linnaeus in 1766 as Sterna fuscata, bearing this name for many years until the genus Sterna was split up. It is now known as Onychoprion fuscatus. The genus name is from Ancient Greek onux, 'claw', and prion, 'nail'. The specific fuscatus is Latin for 'dark'. Colloquially, it is known as the wideawake tern or just wideawake. This refers to the incessant calls produced by a colony of these birds, as does the Hawaiian name ʻewa ʻewa which roughly means 'cacophony'. In most of Polynesia its name is manutara or similar – literally 'tern-bird', though it might be better rendered in English as 'the tern' or 'common tern'. This refers to the fact that wherever Polynesian seafarers went on their long voyages, they usually would find these birds in astounding numbers. It is also known as kaveka in the Marquesas Islands, where dishes using its eggs are a delicacy. The sooty tern has little interspecific variation, but it can be divided into at least two allopatric subspecies. Some recent authors further subdivide the Indopacific population into up to 8 subspecies altogether, but much of the variation is really clinal. The affinities of eastern Pacific birds (including the famous manutara of Easter Island) are most strongly contested. Onychoprion fuscatus fuscatus (Linnaeus, 1766) – Atlantic sooty ternUnderparts white. Breeds Atlantic and Caribbean. Onychoprion fuscatus nubilosus (Sparrman, 1788) – Indopacific sooty ternUnderparts light grey in fresh plumage, dull white in worn plumage. Breeds from Red Sea across Indian Ocean to at least central Pacific. Some authors restrict this taxon to the Indian Ocean population and use the following subspecies for the birds from Indonesia to the Americas: This is a large tern, similar in size to the Sandwich tern (Thalasseus sandvicensis) at 33–36 cm (13–14 in) long with an 82–94 cm (32.5–37 in) wingspan. The wings and deeply forked tail are long, and it has dark black upperparts and white underparts. It has black legs and bill. The average life span is 32 years. Juvenile sooty terns are scaly grey above and below. The sooty tern is unlikely to be confused with any tern apart from the similarly dark-backed but smaller bridled tern (O. anaethetus). It is darker-backed than that species, and has a broader white forehead and no pale neck collar. The call is a loud piercing ker-wack-a-wack or kvaark.