Tigalda, about 12 miles (19 km) long, is one of eight named islands in the Krenitzin group, part of the Fox Islands in the eastern Aleutians, about 19 miles (31 km) east of Akutan and 62 miles (100km) east-northeast of Dutch Harbor, Alaska. Many of the larger Aleutian islands rest on a mafic volcanic basement, possibly Late Cretaceous in age, overlain by Paleocene volcanic and sedimentary rocks. Eocene and Oligocene volcanic arc deposits record the region’s long history of volcanism and deformation along the Pacific-North American plate boundary. The island’s south coast takes the full force of Gulf of Alaska storms and is severely eroded, leaving abundant sea stacks, steep and often vertical columns of rock standing off cliffs and headlands. The columnar stacks form as waves exploit joints in a headland. Hydraulic action widens these fractures into sea caves. A cave that breaks through becomes an arch, and when the arch roof collapses it leaves a stack. Differences in rock resistance speed the process. Eventually the stack is worn down to a stump by subaerial erosion, leaving a wave-cut platform or submerged reef.

The Aleutian Islands have the longest history of archaeological and anthropological investigation in Alaska, and Tigalda has a substantial Unangan (Aleut) history. The island was called Kagalga by Krenitzin and Levashev in 1768, and its Aleut name, Qigalĝan, was published as “Tigalda” by Captain Friedrich von Lütke in 1836. The Russian Orthodox priest Ioann Veniaminov, later Saint Innocent, reported a village on the north coast of the island called “Tigaldinskoe” with 91 residents in 1833. Earlier accounts describe five settlements and at least 500 inhabitants. The community’s history includes displacement, epidemic disease and the consolidation of surviving residents at other Krenitzin Island settlements. Orthodox missionaries followed, building a chapel on Akun in 1843 and another on Tigalda in 1844, consecrated to Saint Ioann Listvinnik. The island’s ochre deposits were valued locally as pigment. Tigalda is part of the Fox Islands group which includes Unimak, Unalaska, Sedanka, Akutan, Akun, and Umnak islands, where red foxes are indigenous. Tigalda Island does not have a history of fox farming, unlike other areas in Alaska where the industry flourished after 1750 when Russians first released Arctic foxes on Attu.

Sea stacks can be ecologically important as a refuge for birds. The bald eagle (Haliaeetus leucocephalus) is a bird of prey found near bodies of water that provide access to an abundant food supply and nesting habitat. They are top level predators in the Aleutian food web and feed opportunistically on fish, seabirds, carrion and other available prey. Live fish are caught directly from the water by dramatic aerial maneuvering and diving talons-first into the water without fully submerging. This sea eagle builds the largest nest of any North American bird, up to 13 feet (4 m) deep, 8 feet (2.4 m) wide and about a ton in weight. Along the coast of the Alaska Peninsula and the Aleutian Islands where there are no trees, the bald eagle nests on the ground. Because of various terrestrial predators including rats, foxes and bears, the preferred location for a ground nest is on sea stacks that afford excellent visibility and defensive isolation. A 1999 breeding population estimate by island group in the Aleutian Islands reported more than 25 breeding pairs in the Krenitzin Islands. Parts of the Aleutians have received federal wildlife protection since 1913. Today, Tigalda is uninhabited and forms part of the Alaska Maritime National Wildlife Refuge, which protects important wildlife habitat and cultural resources. Read more here and here. Explore more of Tigalda and Krenitzen Islands here: