SIB “Bird of the Week” – Least Tern

Least Tern – Sternula antillarum
Length:  9″; Wingspan: 20″; Weight: 1.5 oz.

Courtship of Least Terns - Ed Konrad
Courtship of Least Terns – Ed Konrad

The Least Tern arrives to Seabrook Island in mid-April each year.  It is the smallest tern in North America.  Look for a small, graceful tern with a black cap, white forehead, and yellow bill. Their legs are yellow.  Like most other terns, they plunge dive for small fish.

As of this year, we are so lucky to have these birds return to Seabrook Island to nest.  You will find them nesting and flying in the dune areas above high tide on North Beach in the area of the new inlet cut.  This area was marked off with signs and rope by DNR during the first week of May.  Extra high tides along with disturbances by humans and dogs may cause considerable loss of nests, eggs, and young in this species.  Least Terns are now listed as threatened in South Carolina.

Least Terns are vocal and defend their nest areas by flying at intruders (please avoid their nesting areas during the breeding season if you find a colony).  They “chitter” constantly as they feed, when they take flight and if disturbed.  It is a metallic sharp call that sounds like this.

They are monogamous and breed at 2-years old,  generally having one brood (sometimes 2).  Least Terns nest on open beaches or river margins, usually near water. They may also nest on flat roofs. The nest is a shallow scrape in the sand, usually unlined, and is built by the female.  They lay 1-3 eggs which both sexes incubate for 20-22 days.  In very hot weather, adults may wet their belly feathers and cool the eggs.  Young leave the nest a few days after hatching and hide nearby.  Both parents care for the chicks.  They can fly after 19-20 days or so but remain with their parents for 2-3 months. Please check-out the great photos and captions of Least Tern courtship below.

After breeding, adults and young frequently rest on the beach together (the young are darker with faint barring on the back) and may mingle with Black Terns in the later summer.

A group of least terns are collectively known as a “straightness” of terns.

Besides North Beach, you may also see these beautiful and graceful birds near the ponds of the golf club, at Bohicket Marina and at various other ponds on Seabrook Island.

(See the range map following the photographs below.)

If you would like to learn more about this bird visit:

(Source: Carl Helmes,; edited by Nancy Brown; photographs by Ed Konrad)

This blog post is part of a series SIB will publish on a regular basis to feature birds seen in the area, both migratory and permanent residents.  When possible we will use photographs taken by our members.    Please let us know if you have any special requests of birds you would like to learn more about.

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