Onychoprion aleuticus
The Aleutian Tern (Onychoprion aleuticus) is a medium-sized tern, measuring 32-36 cm in length with a wingspan of 76-81 cm and weighing around 100-140 grams. Breeding adults sport a distinctive white forehead patch extending to just behind the eye, contrasting sharply with a black cap, black bill, and black legs. Their upperparts are pale grey, while the underparts are pure white, often with a subtle white crescent below the eye. This unique head pattern, coupled with its entirely black bill,...
This tern predominantly inhabits low-lying coastal regions, barrier islands, and open tundra near the sea for breeding. It is primarily a marine species, foraging over shallow coastal waters.
Their diet primarily consists of small fish such as sandlance, capelin, and juvenile salmon, supplemented by marine invertebrates like shrimp and squid, all caught through plunge-diving.
Aleutian Terns are diurnal and highly colonial nesters, typically forming dense colonies on remote beaches or low-lying islands, often alongside Arctic Terns. Their foraging strategy involves agile flight and shallow plunge-diving to catch small fish from the ocean surface, and they may also hawk...
The Aleutian Tern has a disjunct breeding range extending across the North Pacific. Its primary breeding grounds are found along the coasts of Alaska, including the Seward Peninsula, islands of the Bering Sea, the Aleutian Islands, Cook Inlet, and Bristol Bay. Across the Bering Strait, it also br...
Vulnerable
- The Aleutian Tern is one of the most enigmatic terns, with its wintering grounds remaining largely unknown to science until relatively recently. - It is the only species in its genus, *Onychoprion*, that breeds in subarctic, cold northern waters; its relatives are all found in tropical or subtr...