Common Tern

Irish Name: Geabhróg
Scientific name: Sterna hirundo
Bird Family: Terns
Conservation status


Summer visitor from March to October to all Irish coasts.


Usually seen over the sea or over large inland lakes. Slender seabird with narrow, pointed wings, long forked tail and long, pointed bill. Grey above and white below, dark cap to head. Flight light and buoyant, can hover briefly over the sea before diving in. Very similar to Artic Tern (with which it breeds) and told apart by plumage and structure. Common Tern has a longer head and bill and slightly broader wings, which look central on the body. Adults have a orangey red bill, usually with a small dark tip. Underparts are whiter than Artic Tern and there is no contrast with cheek. The wing pattern is useful in separation, Common tern shows a dark wedge in the primaries which develops over the summer and a defuse bar to the trailing edge of the primaries. Common terns have shorter tail steamers, not extending beyond the wing tips. Adult winter plumage, like all terns is different from breeding plumage and can develop in the summer months. Has a white forehead, all dark bill and dark carpel bar. Also has distinctive juvenile plumage with gingery mantle, a dark secondary bar and dark carpel bar. Bill base is orange. Shows a diffuse trailing edge to the primaries. First and second summer plumages are rarely seen in Europe.


A noisy bird when breeding, giving a rapid series of quarrelsome calls


Chiefly fish


Nest colonially on the ground from April to October. Breeds on the coast, with larger colonies in Co. Dublin, Co. Wexford and Co. Galway. Also breeds inland on islets in freshwater lakes, notably in Co. Galway and in Co. Mayo.


Winters in west and south Africa

Monitored by

All-Ireland tern survey in 1995, and through breeding seabird surveys carried out every 15-20 years, the last was Seabird 2000, which was undertaken between 1998 & 2002. Common Terns are also monitored annually at Rockabill and Lady's Island Lake.

Blog posts about this bird


Rockabill 2019 - One week down, plenty to go!

Common Tern flying by the island at sunset, April 2019. (L.Gill)

We’ve finished our first week out here on Rockabill and it certainly did not disappoint. From Storm Hannah to the arrival of the Common Terns, it’s been an interesting week.

Waves breaking over the Bill during a bright spell in Storm Hannah (L.Gill)

Our bird species list is now at 21. Kittiwakes have started to occupy cliff ledges in KittiCity and KittiPoint along with in section 4C and out in the Bill.

Pair of Kittiwakes on a cliff ledge at 'KittiCity' on Rockabill Island. (L.Gill)

Black Guillemots have also started to spend more time on the island rather than rafting up around it. Every morning we go out to count them and our highest count so far has been 213!

Black Guillemots resting on the pier at Rockabill. (L.Gill)

Myself and Andrew have started to settle down into the routine of island life and getting stuck into our work. Emma, the third warden will be arriving tomorrow. All the study sites have now been cleared of tree mallow.

Removing the Tree Mallow vegetation from one of the Lighthouse gardens, to make space for nesting Terns. (L.Gill)
The same garden as above, after removal of all of the Tree Mallow vegetation - plenty of space for Common terns to nest on the ground now! (L.Gill)

We have taken out all the nest boxes from inside the house and sorted them in numerical order ready to go to their various parts of the island. Any nest boxes that were broken have been set aside to be repaired or replaced.

Sorting out some of the 900 nestboxes to be deployed around the island for nesting Roseate Terns! (L.Gill)

For birds that aren’t nesting in nest boxes, their nests will be marked with pegs. We took out all the pegs from last year and sorted them into Common Tern, Artic Tern and Roseate Tern piles. We then sorted all of the Common Tern pegs on bamboo sticks from number 1-250 and Roseate and Artic pegs will soon follow.

We use coded clothes pegs to mark nests on Rockabill - at the start of the season there are a couple of thousand to be sorted out! (L.Gill)

Last night we were treated to a beautiful sunset with Common Terns flying across making for some beautiful shots.

Common Tern silhouettes at sunset, from Rockabill Island. (L.Gill)

Common Tern silhouettes at sunset, from Rockabill Island. (L.Gill)
  • Lorna Gill & The Rockabill Team.

Similar Species

Arctic Tern

Irish Name:
Geabhróg artach
Scientific name:
Sterna paradisaea
Bird Family:

Sandwich Tern

Irish Name:
Geabhróg scothdhubh
Scientific name:
Sterna sandvicensis
Bird Family: