Common Tern

By 04/12/2020Birds

Common terns have long tails which have earned them the nickname ‘sea-swallow’. That is, their Latin species name hirundo means swallow and refers to the tern’s superficial likeness to that unrelated bird, which has a similar light build and long forked tail.


Common tern (Sterna hirundo)


  • Latin name: Sterna hirundo
  • Order: Charadriiformes
  • Family: Lariade
  • Length: 31-35 cm
  • Weight: 110-150 gr
  • Wingspan: 77-98 cm
  • IUCN Status: Least concern

Source: Map Lynx Edicions/BirdLife International


Important: Birds species have different identifying features depending on sex, age and season.

Eye color: Black
Beak: Long thin orange-red beak, with black part on top of the bill
Leg color: Orange, red
Feather colors: Black, grey, white

Immature Common terns:



Common Terns mainly feed on small fish, crustaceans and insects. They take food almost exclusively while on the wing. They feed by plunge-diving, diving-to-surface, or contact-dipping.


Common Tern feeding on a snipefish in the Azores


Common Terns nest on the ground, primarily in open areas with loose substrate, but with scattered vegetation or other cover that will be available for chicks to shelter in within the nesting territory. The reproduction takes place from April to August. The incubation of 2-3 eggs (creamy brown with some black patches) lasts at around 21-22 days. The juveniles will reach the fledgling stage, first flight, at around 25-26 days.
During the first 4 days after chick hatches, the female broods and/or attends the chicks about 70% of time during the day and 90% of time at night. The male broods and/or attends the chicks 40–50% of time during the day but only 10–20% of time at night. Adult Common Terns continue to feed their young for several months after fledging, on into fall migration.


Common terns have a wide repertoire of calls. All calls have a distinctive sharp, irritable timbre. They emit a kit very short and high and also some series of a staccato: kek-kek-kek-kek… very fast . The most distinctive sound is the alarm KEE-yah, stressed on the first syllable. They are often noisy in colonies and very territorial.




Illustration by Ian Willis.


About Marylou

Marylou is a Marine Biologist and Master in Oceanography. She is one of our Marine Wildlife Guide and is responsible for Science Education at TERRA AZUL. Originally from France, she studied in Canada and Belgium and loves being out to sea to share her knowledge with you.