If Jonathan Livingston Seagull had a sidekick, it would probably be a tern. T-e-r-n-s resemble gulls, but are smaller and slimmer with narrow angled wings. Like gulls, they are mostly white birds with embellishments of black and gray. Males and females are alike, most with white bodies, gray-and-white wings, and a black cap more or less elaborate depending on the tern.
     There are Black Terns with black bodies, and Sooty Terns with black wings. Worldwide there may be hundreds of variations on the tern theme of white, black, and gray.
     In flight and in silhouette, terms resemble swallows — long ago they were known as the Sea Swallows. Their aerodynamic bodies and long pointed wings make them graceful, buoyant flyers with great endurance. Certain terns spend much of their lives on the open ocean, while others breed in the interior on rivers, lakes, and marshes.
     A tern on land appears hunkered down and leaning forward, while a gull stands straight up. Many terns have black bills and feet, but some of these also come in yellow, red, and orange. Almost all tern tails are white and many are forked.
     A gull will eat anything, but a tern is discriminating, eating mostly small fish and the occasional insect. “Strikers” is another old name for terns, for the way they hover and dive for food or “strike” into the water.
     These are colonial nesters that crowd together to brood and raise their young. A typical tern nest is only a scrape in the sand. A colony of nesting birds is vulnerable on the beach or sandbar, especially at night. The young are semi-precocial and will walk and swim soon after hatching but remain dependent on their parents for some time.
     The Arctic Tern has been called the world’s greatest migrant for an incredible round-trip migration of 30,000 miles. They fly from the Arctic circle to the tip of Greenland, then to the South Pole, and then back! It’s like a trip around the world every year.
     The terns most likely to be seen in the High Plains are Common, Forster’s, Least, and Black Terns. All but the Black are white birds with gray wings and white forked tails. The Black Tern begins white and turns black in breeding season, at least the head and body turn black, the wings remain dark gray and the tail white.
     The Least Tern is the smallest at 9 inches long with a wingspan of 20 inches. These dainty terns of white and light gray nest along rivers and lakes in the southern High Plains, but only on sand scrubbed clean of vegetation by tide or river action. These same beaches and riverbanks are increasingly used for human recreation. Jet skis, air boats, and off-road vehicles can wipe out a nesting colony with one wrong turn. Add in development, water diversion, and recent area flooding, and it’s likely our breeding Least Terns took a turn for the worse this year.
     Watch your step when you stroll along the sand, and consider the terns as you sing along to that old song inspired by the Bible and sung by, of all people, the Byrds:

To everything
There is a season (turn, turn, turn)
And a time for every purpose,
under heaven.

I learned about terns from the Sibley Guide to Bird Life & Behavior and Birds of North America Online.