Terns are some of the most sleek and acrobatic species of birds in the world. They swiftly swoop, hover, and dive through the skies across North America. With many terns having similar looking plumages, they can be difficult to tell apart. Fortunately, with a little knowledge about tern identification and where they are most expected, it becomes easier to tell them apart.

Wisconsin is home to four species of terns that are annual and fairly common in the state, in addition to one species that is extremely rare. Here is everything that you need to know about the terns of Wisconsin.

Arctic Tern (Rare)

Identification

Arctic Terns in breeding plumage have a clean white body with gray wings, a dark black cap on the head, a reddish orange bill, and short reddish orange legs. In nonbreeding plumage, the black cap is replaced by a black stripe over the eye and the legs and bill are black as opposed to reddish orange.

Range

Arctic Terns are extreme long-distance migrants spending the summer in Northern Canada, Alaska, and the Northern most parts of Europe. They winter in Antarctica, meaning they fly from pole to pole each migratory season.

Diet and Foraging Habits

Arctic Terns feed mostly on fish but will also eat insects. To catch fish, these birds will hover above the water and plunge in headfirst to try and nab prey just below the surface.

Where to Find this Bird

Arctic Terns are a species that is rare in most parts of the continental United States and can usually only be seen during migration. Look for this species near large bodies of water as they typically migrate offshore. Keep an eye out for a short and stout looking tern amongst Common Terns and Forster’s Terns.

Black Tern

Identification

In breeding plumage, Black Terns have gray wings with white on the shoulder area. They have an overall black body and head, black bill and legs, and white underside behind the legs. Nonbreeding Black Terns are much paler with a white head and body and just a small patch of black color near the eye.

Range

Black Terns winter in Northern South America and make their migratory journey north in spring when they spread out across most of Mexico and the continental United States. They breed in South-central Canada and the Northern United States.

Diet and Foraging Habits

Black Terns are very acrobatic as they forage for food and catch prey on the fly. They eat small fish and insects, usually by flying low over marshy areas. One interesting thing about Black Terns is that they do not plunge into the water to catch fish like many other tern species do.

Where to Find This Bird

In winter, Black Terns can be found around coastal habitats but in spring and summer, marshes and swamps become the best place to locate this species.

In Wisconsin, there are a variety of marshes that Black Terns can be found breeding in. One of the best places in the state to find them is Horicon Marsh.

Caspian Tern

Identification

Caspian Terns are extremely large for terns. In fact, they are the largest tern species in the entire world. They are white with gray wings, black legs, and a chunky red bill. Caspian Terns also have a black cap in breeding plumage which fades in nonbreeding plumage and looks more like a black smudge near the eye.

Range

Caspian Terns are extremely widespread in not only North America but the entire world. This species got their name due to the fact that they were common around the Caspian Sea (which they still are to this day). Caspian Terns can be found along the coasts of Australia, Africa, Southern Asia, Europe, and North America.

In North America, Caspian Terns winter in Mexico, Souther California, the Gulf Coast, Florida, and along the Atlantic Coast. They migrate north in spring and nest in parts of Canada, the Western United States, and the Great Lakes.

Diet and Foraging Habits

Caspian Terns primarily feed on fish but will also eat crustaceans and insects. This species feeds in the same way that other terns do; flying above the water to search for food and diving headfirst into the water when they see something they want to catch.

Where to Find this Bird

Caspian Terns frequent ocean coastlines as well as the shores of large inland bodies of water. They are most easy to find during migration when they show up in fairly large numbers along beaches and can be seen and heard flying over the water. In the Midwestern states, the Great Lakes are a fantastic place to find this species.

Common Tern

Identification

In breeding plumage, Common Terns have a white head and body with gray wings, a black cap, an orange bill with a black tip, and orange legs. An important feature in Common Terns that separates them from the nearly identical Forster’s Tern is the color of the primary feathers in adults. In Common Terns they will be dark gray while in Forster’s Terns they will be light gray to white. Nonbreeding adults will not have a complete black cap but rather a partial cap with the front of the head showing white.

Range

Common Terns winter along the Coasts of South America, Central America, Mexico, and the Gulf of Mexico. In spring they move north into Canada and parts of the Northern United States, including the Great Lakes states.

Diet and Foraging Habits

Common Terns eat primarily small fish but will also eat crustaceans and other marine and freshwater invertebrates. They will catch fish from the surface of the water while flying or dive into the water to catch prey.

Where to Find this Bird

Common Terns are birds of coasts and shorelines. They are typically found along large bodies of water such as the oceans and the Great Lakes. They can be seen resting on beaches and sandbars.

In Wisconsin, Common Terns can be found along Lake Michigan in the spring and summer where they will be in mixed flocks of terns and gulls.

Forster’s Tern

Identification

Breeding plumage Forster’s Terns have a white body and white forked tail, orange legs, an orange bill with a black tip, and a black cap going from their neck to their bill. They have light gray wings and light-colored wingtips (which is an import thing to note when differentiating between Forster’s Terns and Common Terns).

Nonbreeding Forster’s Terns look almost the same as in breeding plumage but instead of a full black cap, they have a black streak that covers their eye.

Range

Forster’s Terns winter along the Southern coasts of the United States and Mexico. They migrate north during the spring and breed in Southern Canada, portions of the Western U.S. and specific places along the Great Lakes. Forster’s Terns are year-round residents of Eastern Texas and Southern Louisiana in addition to parts of the Atlantic Coast near North Carolina and Maryland.

Diet and Foraging Habits

Forster’s Terns feed primarily on fish which they catch in a very distinctive manor. These terns will hover above the water, and suddenly plunge themselves below the surface. In addition to fish, they will also eat insects.

Where to Find this Bird

Forster’s Terns can be found in both freshwater and saltwater marshes in addition to coast lines.

In Wisconsin, these birds can be found along the coasts of the Great Lakes during migration and breed in marshes over the summer. One marsh in particular where Forster’s Terns can be found is Horicon Marsh.

Summary

Terns are quick and acrobatic birds that can sometimes be difficult to identify since so many of them are similar looking. Knowing the species that are expected in your state can be instrumental in identifying which one you are looking at in the field. Hopefully, this article has helped in answering some questions about the terns of Wisconsin.

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