Common Terns are small to medium-sized seabirds considered one of the most widespread terns in North America. Breeding adults have distinct black caps and napes and narrow, pointed, orange bills.
They are gray and white and have orange legs. Their wings are dark-tipped and form a dark wedge on the upperside of the wingtips. Their tails are white and deeply forked.
Non-breeding adult Common Terns lose the front portion of their black caps and are left with white foreheads and partial grayish-black hindcrowns and their legs and bills turn black.
Juveniles are a pale version of non-breeding adults. They have a brownish-gray wash to their crowns and napes and some ginger patches on their foreheads that gradually turn white by autumn.
- Sterna hirundo
- Length: 13 – 16 in (33 – 41 cm)
- Weight: 5.15 oz (146 g)
- Wingspan: 30 – 31 in (76 – 79 cm)
Common Terns are found around the world. Those that breed in the northern hemisphere migrate to the south for winter. Some remain all year in the tropics and southern hemisphere.
Habitat And Diet
You can find Common Terns close to the water (whether freshwater or saltwater) as long as it’s on any open flat habitat like beaches, firm dune areas, salt marshes, or islands during their breeding season. In winter, Common Terns occur anywhere that has access to fish.
Fish smaller than seven inches are the preferred prey of Common Terns. They will “plunge-dive” into the sea, ocean, or freshwater lakes and rivers to capture them. Normally, they will only stay submerged for a second just enough to catch the fish. When Common Terns have chicks to feed, they may opt to take larger prey and may add insects, worms, leeches, squids, shrimps, prawns, and mole crabs to their diet.
Common Tern Calls:
Nests of Common Terns are usually built by the breeding couple by making shallow depressions or “scrapes” on the ground lined with some seaweed, stones, or shells. They prefer areas that have sand, gravel, shells, or pebbles and are close to the water. Ideally, there should also be some low vegetation to act as cover for their young.
The female lays one to four eggs but there may be more when another female uses the same nest for her eggs. Incubation lasts between twenty-one to twenty-five days and is done by both parents.
Common Terns can locate their nests in a large colony even when they’re buried or displaced.
In the 19th century, there was a huge decrease in the population of Common Terns due to fashion. Entire stuffed Common Terns were used to make hats in Europe and North America.