Caspian Tern

Hydroprogne caspia

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The Caspian Tern, Hydroprogne caspia, is the largest tern inhabiting the Lake Champlain Basin, and is, in fact, the largest tern in the world. After Double-crested Cormorants denuded parts of Island C of Lake Champlain’s Four Brothers Islands in eight years ago, Caspian Terns found the bare ground appealing and began nesting there.

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Newcomers to Lake Champlain

Four Brothers Islands, Lake Champlain

Relative newcomers to Lake Champlain – the first recorded nesting was in 2001, when a pair was found on Young Island, off of North Hero and on Popasquash Island, off shore between St. Albans and Swanton. By 2004 Caspian terns began nesting on Four Brothers Island and as of 2007 that colony had 50 pairs of birds. The island now hosts over 100 nesting pairs – a ten-fold increase since they were first confirmed on Island C ten years ago.

Although the Caspian Tern is rare to Lake Champlain, it is not listed as threatened or endangered in either Vermont or New York. Much of the Caspian Tern’s core population is found in the Great Lakes region, but that population is suffering from avian botulism, which is killing thousands of terns. Lake Champlain hosts the only Caspian tern colonies in Vermont and the only other New York colony is on Little Galoo Island in Lake Ontario..

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Caspian Tern Characteristics

The same size as gulls, and with similar white plumage, Caspian Terns has bright orange bills and swept-back black crests. They are one of three species of terns that can be found on Lake Champlain.  They can be found throughout much of the world, but rarely in large numbers. While hunting, terns dive down on prey, un-like most gulls. They also hunt with their heads lowered to the water, a posture quite different from soaring gulls. Their voice, a raspy ‘kowk’ also differs from that of gulls. While Caspian terns have increased in number, their cousins, common terns have faced troubles.  In the late 1960s, between 300 and 400 pairs of common terns nested on Lake Champlain, but by 1988 the population had fallen to just 50 pairs. The species is currently listed as ‘Endangered’ in Vermont and ‘Threatened’ in New York. The birds nest on small rocky islands in the lake. Work by Audubon Vermont, the Vermont Non-game and Natural Heritage Program, and the Lake Champlain Land Trust has increased the number of nesting terns since the late 1980s and now between 160 and 200 pairs nest on the lake.

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Interesting Trivia About Caspian Terns:

Caspian Terns may begin to vocalize while still in the egg. When an adult gives a ‘Fish Call’ signaling their return to the nest with food, the soon-to-be chicks may respond with begging calls before they are even hatched.

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