Least Tern

Sternula antillarum

least_tern.jpg

Image of a least tern
MDC Staff
Endangered
Species of Conservation Concern
Family

Laridae (gulls, terns, skimmers) in the order Charadriiformes

Description

The least tern is the smallest tern in America, gray above and white below. The head is white with a black cap and nape and a white forehead. The outermost primaries are black, the bill is yellow-orange with a black tip, and the legs are yellow. The tail is short and deeply forked. Late-summer juveniles are brownish above with dark Vs on the back and have dark eye patches. The voice is high and shrill, with 2 or 3 syllables.

Size

Length: 9 inches (tip of bill to tip of tail); wingspan: 20 inches.

FG-0116_Least_Tern.mp4

Video of least tern.

Least_tern_chicks.jpg

Least Tern chicks
Least Tern chicks
Habitat and conservation

This rare summer resident forages over water for small fish, which it captures by diving into the water. It is listed under the federal Endangered Species Act. In the past, least terns nested on sandbar islands in the Mississippi and Missouri rivers. Human alterations to the rivers destroyed much of their habitat. Today, several hundred pairs still nest on a few islands in the lower Mississippi from Cape Girardeau south. One day they may nest again on sandbar islands on the Missouri.

Foods

This bird dives into water to catch its prey, which is almost entirely small fish. Nests are generally located near shallow water where small fish are abundant.

image of Least Tern distribution map
Distribution in Missouri

May be found on the Mississippi River from Cape Girardeau and south, but potentially could appear on other big rivers, too.

Status

Rare summer resident foraging over water, particularly the Mississippi River from Cape Girardeau and south. Rare transient otherwise. Our particular subspecies is the interior least tern (Sterna antillarum athalassos), and both Missouri and the U.S. federal government have listed it as Endangered.

Life cycle

This species arrives in late April to May. Females lay 1–4 eggs in late May, and incubation lasts about 20–25 days. Young reach fledgling stage in 3–4 weeks but remain with their parents until migration. They depart our state in August and September. No one knows for sure where they overwinter. Least terns can live 10 years or more.

Human connections

It’s an intrinsic part of our human nature to want to find the answers to questions, and many questions remain about this small tern. We’re not even sure where it spends the winter. For the sake of our curiosity alone, it is important for this species to survive.

Ecosystem connections

This bird preys on small fish, and its pre-fledgling young provide food for various other predators. As a migratory species, this bird plays a role not only in Missouri, but also where it overwinters as well as the places it passes through as it migrates.