Aleutian Tern
Onychoprion aleuticus
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
Swallow-tailed Gull
Creagrus furcatus
The swallow-tailed gull has no structural or plumage differences between the male and female. In the breeding season, the adult has a black plumaged head and a bright red fleshy rim around each eye. Outside the breeding season, the head is white and the eye rim becomes black. It has a grayish upper breast, gray mantle, and black wingtips. The mostly black bill has a contrasting white tip. Voice: Calls and displays are quite different from other gulls, most resembling the vocalisations of the black-legged kittiwake and Sabine's gull. The loudest and most commonly heard call is an alarm referred to as "rattle-and-whistle", a gurgling scream made with the head moving side to side. This call is contagious, with other birds joining in without seeing the cause.
ID text from Wikipedia, CC BY-SA 4.0
Learn this pair in the BeakBrain App
Photo and call practice. Coming soon to iPhone and Android.
Play today's Daily BirdPhotos and recordings are credited to their authors under the licence shown. Full profiles: Aleutian Tern and Swallow-tailed Gull.