Common terns are a threatened bird species in Minnesota, due in part to exploding populations of the competing ring-billed gull. On Interstate Island in the St. Louis River estuary near Duluth, researchers protect and study nearly 200 breeding pairs of common terns, bolstering their populations in both Minnesota and Wisconsin, whose border runs through the middle of the island.

During the May-to-July nesting season, this onetime dredge spoil is a screeching nexus of avian activity, with the terns nesting in an exclosure amid a much larger encampment of 13,000 pairs of ring-billed gulls and a few dozen herring gulls.

Amid the cacophony, researchers track the number of tern nests and the chicks they produce, placing bands on every chick to learn more about them.

See more images of the common terns of Interstate Island.