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Boreal Community Media

Mike Jacobs: Terns deserve more attention for their elegance and beauty

Jul 22, 2019 09:37AM ● By Editor
Forster's tern. Illustration by Mike Jacobs

Always in Season by Mike Jacobs of the Grand Forks Herald - July 21, 2019

The terns are wetlands birds, and they often nest in large colonies, as gulls do. They are superb aerialists, as gulls are – but gulls are nowhere nearly as acrobatic or elegant as terns can be.

As a group, the terns are overlooked. Often, these graceful, elegant birds are lumped with the gulls, which they closely resemble, both in appearance and behavior.

The terns are wetlands birds, and they often nest in large colonies, as gulls do. They are superb aerialists, as gulls are – but gulls are nowhere nearly as acrobatic or elegant as terns can be.

All of this is on my mind after spotting Forster’s terns on a celebrated wetland in Ramsey County.

Forster’s is arguably the most elegant of the terns. Its flight is direct and regular as it courses over open water – until it spots prey. Then it dives face forward and bill down into the water, emerging soon after, often with a minnow in its mouth.

This maneuver is so sudden and so surprising that it never ceases to startle me. I’ve watched terns closely and tried to anticipate their dives. Most of the time, however, they simply disappear from the view through my binoculars and I’m left to marvel yet again.

North Dakota has five kinds of terns, and you could get into an argument about which is the most abundant. I’m taking a chance here – but I’m going to list them in order of apparent abundance. That might be code for how often I encounter each species.

The winner, I think, is the easiest to identify. This is the black tern, a regular nester on wetlands of any size. I often see them along U.S. Highway 2 as they cross wetlands near Devils Lake. The black tern is easily recognized. Its color and its swallow-like flight sets it apart from other species of terns and from the gulls, as well.

The lake area is a haven for terns. 

The Forster’s tern nests there, and I saw them on a circuitous drive through Ramsey County north of Devils Lake. Kenner Marsh, a restored wetland near Penn, N.D., seems to be a dependable place to find them. Today’s marsh was created to mitigate damage from drainage in the Devils Lake basin.

Forster’s is the most elegant of a family that runs toward elegance. The size of a small gull, Forster’s tern has a long, quite deeply forked tail that streams behind the bird in flight. A flying tern displays a two-toned wing. Although the wings are white or pale gray, they are not monochromatic, showing flashes of white as the birds fly. This is perhaps the most useful way to identify the birds at a distance. Other pointers are the tail, of course -- though its fork isn’t evident when the bird is flying -- and its relative trim shape. Forster’s terns don’t bulge in the belly.

The common tern – probably less abundant in our area despite its name – is similar, except that the tail is shorter and less forked, the wings lack the two-toned effect in flight and the belly is rounder than the flat keel of the Forster’s tern.

These species sometimes occur together, but the common tern tends to be a bird of larger water surfaces – a lake tern, so to speak – while Forster’s is a “marsh tern,” frequenting areas with emergent vegetation, including reeds and cattails.

Another tern species appears to be increasing in North Dakota. Long associated with Manitoba’s lakes, Caspian tern has turned up more frequently in recent years; nesting is probable, but farther west than the Red River Valley.

The Caspian tern is a larger, darker bird, more likely to be confused with a gull, perhaps, than with another tern. But it has the characteristic tern attributes: a rather heavy beak for its size, a black cap on the head and otherwise overall pale plumage.

Finally, North Dakota has a small population of the endangered interior least tern. These birds nest on sandbars in the Missouri River between Garrison Dam and Lake Oahe. This is a chancy environment for the ground-nesting terns. Irregular releases from Garrison reservoir sometimes destroy their nests.

Of these species, Forster’s is limited to North America. Its breeding range includes most of the northern Great Plains and the Great Basin area of Utah, Nevada and California.

Thomas Nuttall, a pioneering naturalist who visited what is now North Dakota, named Forster’s tern for a German bird lover who was the ornithologist assigned to Captain Cook’s transpacific voyage. Likely, Forster never saw the bird alive – and so missed its unusual grace and beauty.

Nuttall himself is the namesake of Nuttall’s violet – the beautiful yellow violet of the prairie in springtime.

To read the original article and read more of Mike Jacob's outdoor columns, follow this link to the Grand Forks Herald website.