Aleutian Tern vs Bridled Tern

Aleutian Tern

Onychoprion aleuticus

Medium120 gCoastal

The Aleutian tern is medium-sized tern (32–39 cm (13–15 in) long), with a 75–80 cm (30–31 in) wingspan, a short pointed bill and a long, deeply forked tail. It weighs 84–140 g (2.9–5.0 oz). Breeding adult and juvenile are the only plumages likely to be encountered in North America. Breeding adult (definitive alternate plumage) has a white forehead, a black cap, a mid-grey mantle with darkish grey underparts, and white rump and tail. Its underwing is whitish, with dark-tipped primaries and a diagnostic dark bar on the secondaries. The Aleutian tern has a black bill as well as black legs. Voice: The Aleutian tern is associated with different calls reported in the literature. Their call can be distinguished from the common tern ones, since it has a higher pitch and is characterized by a soft and rolling whistled tone. The most distinctive sound is the choppy "chif-chif-chu-ak" described by Olsen and Larsson in 1995, less harsh than the sustained note of the Arctic tern.

ID text from Wikipedia, CC BY-SA 4.0

Photo: usgs.gov · Public domain

Bridled Tern

Onychoprion anaethetus

Medium119 gMarine

This is a medium-sized tern, at 30–32 cm in length and with a 77–81 cm wingspan similar to the common tern in size, but more heavily built. The wings and deeply forked tail are long, and it has dark grey upperparts and white underparts. The forehead and eyebrows are white, as is a striking collar on the hindneck. It has black legs and bill. Juvenile bridled terns are scaly grey above and pale below. This species is unlikely to be confused with any tern apart from the similarly dark-backed sooty tern and the spectacled tern from the Tropical Pacific.

ID text from Wikipedia, CC BY-SA 4.0

Photo: Dr. Raju Kasambe · CC BY 4.0

Photos and recordings are credited to their authors under the licence shown. Full profiles: Aleutian Tern and Bridled Tern.