by Frank Keim
I first saw these small terns while helping some friends fish for salmon in the Bristol Bay area near the small village of Clark’s Point. The colony there was quite large at that time, but since then it has been substantially diminished by egging and harassment by cannery workers and dogs.
Since Aleutian terns are timid birds, they are much more vulnerable to disturbance than their close cousins, Arctic terns. I know from experience that when I approached their colony in Clark’s Point to watch them, they simply flew away rather than do a frontal attack on my head as Arctic terns do. They are also much more polite birds in that they don’t defecate on you during their bombing runs!
I admit to never having seen the Aleutian tern in the YK Delta area. Probably because they make their nests so close to the edge of the ocean on open islands, sandbars or beaches with dense low ground cover. Even so, they mostly forage offshore in the Bering Sea, flying and hovering low over water, then dipping down to take food from just under the surface, unlike their cousins who hover and plunge straight down into the water to capture their prey. Preferred foods of the Aleutian tern are small shrimp and other crustaceans, minnows and insects.
As soon as they get back to the Delta in mid-May from their winter home in the western Pacific Ocean near the Philippines and Indonesia, they find mates and settle down to searching for a good nesting site near the sea water on a low sandspit or beach, among grasses or other vegetation.
Not much is known about their courting displays, but they are probably similar to those of Arctic terns, who take part in aerial displays, wing-raising on the ground and courtship feeding. The nest is an inconspicuous shallow depression in moss, matted grass, sedges and other low vegetation. They usually nest in small colonies, often with Arctic terns, but unlike their cousins, Aleutian terns do little or nothing to defend their nests against predators or intruders and simply fly away at the approach of danger. Those that nest near Arctic terns, however, almost certainly benefit from their more aggressive behavior in defense of the colony.
After laying 2-3 buff to olive-colored, dark brown-splotched eggs, probably both sexes incubate the eggs for 22-23 days, and after hatching, both parents bring food for the young. 25-31 days later the young birds take their first flight, then hang around the colony for another one or two weeks learning feeding strategies from their parents and other adult birds.
Sometime in early to mid-August they head back to their open-ocean (pelagic), wintertime feeding range in the tropical waters of the western Pacific near the Philippines, Indonesia and Malaysia. Information about their whereabouts during the winter months was completely unknown until the late 1980’s, so for good reason we still know much less about this nomadic bird than about its even farther ranging cousin, the Arctic tern.
I was told by elders in Hooper Bay and Scammon Bay that they had two names for the Aleutian tern, Nacallngaar(aq) or Nacallngaq. Both names refer to its black cap. The Yup’ik dictionary also lists the Nushagak River (Dillingham area) name as Tegalqingayar(aq). Its scientific name, Onychoprion aleuticus means, “saw-clawed tern found near the Aleutian Islands.” The saw-shaped claws on their toes enable them to grip slippery surfaces like ice pans they may land on while foraging in the Bering Sea in the spring. Their common name, “tern” derives from Latin, sterna, which in turn derives from Old Engish, stearn, and more distantly from the Old Norse, therna.