Aleutian Tern vs Saunders's Gull

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

Saunders's Gull

Saundersilarus saundersi

Medium198 gCoastal

This is a very small species of gull with a length of just 33 cm (13 in) and, among gulls, only the little gull is smaller. Adults have a black hood and nape during the breeding season. It is very pale with a white body and tail, pale grey wings. Non-breeding birds have a mottled grey hood and nape, and white-tipped wings with black markings on the primaries. Immatures are distinguished by having a narrow black tail band and some dark mottling on the upperwing. The legs are dark red-brown, and the short bill is black; the body is squat.

ID text from Wikipedia, CC BY-SA 4.0

Photo: Kim, Hyun-tae · CC BY 4.0

Photos and recordings are credited to their authors under the licence shown. Full profiles: Aleutian Tern and Saunders's Gull.