What is a Least Tern?

The least tern is primarily a New World bird, and it is the smallest species in the tern family, which is closely related to gulls. Their length is about 9 inches (23 cm), and they weigh about an ounce (28 gm). Least terns have gray and white bodies with black markings on their heads and yellow beaks. The birds generally prefer habitat near the sea, and they are known to be skilled at catching small fish. The least tern is listed as an endangered species.

These birds migrate south in the winter, and they can be found in many areas, from California to South America and certain parts of the east coast of the United States. There was a time when their feathers were highly prized for ornamental use in hats, and this was one of the first things to drastically reduce their population numbers. This threat resulted in the birds receiving protected status in 1918, and their population number recovered for a while. In more recent times, human activity around their breeding grounds has had a detrimental effect on their numbers. The least tern is not very tolerant of interruptions when nesting, and the birds like to breed in the same sort of places people like to use for commercial beaches.

The primary food for the least tern is smaller fish. They have good eyesight, which allows them to see beneath the surface of the water while flying above. When they see a good target, the least tern will generally make a quick, accurate dive to catch it. In some circumstances, they've also been known to prey on other small creatures like crabs and insects, but fish are their favorite food.

This species has a fairly elaborate courtship ritual involving aerial displays and the male offering food gifts to the female. They like to put their nests on the beach in very open areas that are relatively distant from the water. They make their nests by digging a depression into the soil. Least terns tend to nest in large colonies, sometimes including as many as 200 birds.

Eggs are generally lain in May and June, and a clutch of two eggs is a fairly typical number. These birds have a reputation for being aggressive when defending their eggs. Both parents help in incubation, which takes approximately 20 days. The infant birds will generally begin leaving the nest when they reach 20-days-old, and they have a lifespan of about 20 years.