Tiny but tenacious, the least tern is the smallest tern in North America and one of the most imperiled.
Adult least terns are only about 9 inches long - but their wings are almost as long as their bodies, enabling them to travel long distances over open water. These strong wings come in handy, since Tampa Bay's least terns travel to South America every winter, returning to Florida in the spring to court and raise their young.
Least terns are easily recognizable by their black-tipped yellow bill, black cap mottled with white, and forked tail. Their bodies and wings are white. They manly dine on small fish, and can frequently be seen hovering over the bay, then plummeting straight down to the water to snatch a tasty anchovy or herring. Food is a significant part of their courtship, with male terns bringing fish to a female they hope to interest. If the female accepts a suitor's fish offerings, they become a pair.
Least terns nest in colonies, or groups, on the beach, digging small depressions called "scrapes" in sand or gravel and laying 2-3 extremely well camouflaged eggs. In fact, you could walk with on the eggs or the equally well camouflaged chicks and never know. That's why it is so important to obey no trespassing signs posted on sections of area beaches where least terns and other beach-nesting birds (including plovers and black skimmers) have set up house.
Least terns need quiet, undisturbed places in which to raise their babies. But Florida's beaches are so heavily used by people, and surrounded by homes, condominiums or hotels, that a majority of least terns in Florida now are nesting on gravel-top roofs. As these roofs are converted to newer more energy-efficient surfaces, the state's least tern colonies may soon find themselves with "nowhere to tern."
According to Eckerd College researcher Beth Forys, 763 pairs of least terns nested on rooftops in Pinellas County in 2007, compared with 425 on protected or partially protected natural beaches such as Egmont Key or Three Rooker Bar. Sadly, about 80% of Florida's least tern population now nests on rooftops instead of beaches. The birds are considered a threatened species in Florida.
Members of the St. Petersburg Audubon Society have been monitoring rooftop colonies of least terns in Pinellas County for several years, and even use a tool called a "chick-a-boom" (a container on a long pole) to put back in place tern chicks that wander off their rooftop havens and fall to the ground. If you'd like to be a volunteer "chick-checker" during the April-August nesting season, contact Monique Abrams at (727)492-8990.
St. Pete Audubon, with funding from the Tampa Bay Estuary Program, also has produced a story and activity book called "Tina Tern" that highlights the life and adventures of a young tern born on a Pinellas County rooftop. The book can be downloaded at http://www.tbep.org/press/pdfs.html.