This week’s seabird is the most widespread North American tern: the Common Tern.
Common Tern (Sterna hirundo)
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.
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
Ocean beaches, bays, lakes, lagoons. Usually found on the coast but less common inland. Winters in tropical or subtropical waters.
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.
A Common Tern defends its territory (Image by Michelle Kinsey Bruns via wikimedia commons)
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.
A high keeeyurr that descends in pitch; a short kip call
- 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.