Common Tern: Seashore Saturday

This week’s seabird is the most widespread North American tern: the Common Tern.

Common Tern (Sterna hirundo)

Description:

Common Terns are are white with a black cap and considered medium-sized terns. Their tail feathers are forked up. Breeding adults have an orange-red bill that features a dark tip. Their backs are grays and legs are orange. Nonbreeding and first year birds have a dark carpal bar on their upper wings and black feet/tail feathers. Juveniles have an orange bill and a brown-striped back.

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Adult breeding Common Tern  (Image via animilia-life.com

Range:

Breeding (summer): Eastern Canada and Northeast Atlantic Coast Migration: Midwest, Atlantic and Pacific Coasts and some parts of Western United States Winters: coasts of South America and Caribbean Islands

Habitat:

Ocean beaches, bays, lakes, lagoons. Usually found on the coast but less common inland. Winters in tropical or subtropical waters.

Food:

Fish, crustaceans, insects, shrimp. Common Terns forage by hovering over the water and plunge diving. They may also catch insects in the air or steal food from other terns.

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A Common Tern defends its territory (Image by Michelle Kinsey Bruns via wikimedia commons)

Breeding/Nesting:

Common Terns breed in large colonies found on rocky or sandy islands. They usually start to breed between 3-4 years of age. Pairs of groups may perform aerial courtships where they fly high in the air. On the ground pairs will bow and strut. Males will present a fish to the females. Both sexes will participate in choosing a nest site. Nests are usually a scrape in the ground but may be lines with natural materials. Both parents will incubate 1-3 eggs for 21-25 days. Young will remain on the nest for a few days after hatching and take their first flights in about 22-28 days. The chicks will stay with their parents for about 2 months.

 

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An adult and chick (Image by Kevin T. Karlson via ny.audubon.org)

Sounds:

A high keeeyurr that descends in pitch; a short kip call

Fun Facts:

  • Common Terns who live at the coast drink saltwater. They have nasal glands that help excrete excess salt like many other seabirds do.
  • They are strongly migratory and are considered long-distance migrants. Populations usually move north before staring their migration southward.
  • Common Terns have circumpolar distribution. There are 4 subspeices that are found in subarctic and temperate regions of not only North America, but also Asia and Europe.
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Author: BirdNation

I am an avid birder, teacher, and nature lover. I primarily birdwatch throughout New Jersey and Eastern Pennsylvania.

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