Arctic Tern
| Irish Name: | Geabhróg artach |
| Scientific name: | Sterna paradisaea |
| Bird Family: | Terns |
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Conservation status
Conservation status
Status
Summer visitor from March to September to all Irish coasts. Winters off south Africa and as far south as Antarctica.
Identification
Usually seen over the sea. 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 Common Tern (with which it breeds) and told apart by plumage and structure. Arctic tern is smaller, with a smaller head, neck and bill and slightly narrower wings, which look forwardly placed on the body. Very short legs. Adults have a blood red bill, usually with no dark tip. The underparts are greyer than Common Tern and there some contrast with the cheek. The wing pattern is useful in separation, Arctic terns shows no dark wedge in the primaries but shows a distinct trailing edge. Arctic terns have longer tail steamers, extending beyond the wing tips. Adult winter plumage, like all terns is different from breeding plumage, but is only seen in the wintering range. Also has distinctive juvenile plumage, with some brown in the mantle, a dark carpel bar and white secondaries. Shows a distinct trailing bar to the primaries, bill darkens rapidly.
Voice
Similar to Common Tern.
Diet
Marine fish, crustaceans and insects.
Breeding
Mainly a coastal breeding bird, but in Ireland the species also breeds inland on the fresh water lakes of Lough Corrib (Co. Galway) and Lough Conn (Co. Mayo). More colonies are found on the west coast with Co. Wexford, Co. Kerry, Co. Mayo and Co. Donegal having the largest number of birds
Wintering
Considered to have the longest migration of all birds, utilizing the summer of both hemispheres.
Monitored by
All-Ireland tern survey in 1995, and through breeding seabird surveys carried out every 15-20 years. Arctic Terns are also monitored annually at Rockabill and Lady’s Island Lake.
Lady’s Island Lake, near Rosslare, in County Wexford has up to 300 pairs. As well as other tern species.
Lady’s Island Lake, near Rosslare, in County Wexford has up to 300 pairs. As well as other tern species.
Blog posts about this bird
Rockablog: Eggs, eggs, and more eggs!
At the end of our last update, we mentioned that the terns had just begun landing on the island. Now, it's hard to imagine a time when they weren't here! While we've been very busy monitoring the island's changes, the terns have been even busier. Over the past two weeks, they have transitioned from cautiously inspecting potential nest sites to enthusiastically and vigilantly protecting their nests and eggs.
We can confirm that all three species—common, Arctic, and Roseate Terns—are nesting on the island, with different pairs at various stages of nesting. Some terns have already begun incubating their full clutches of three-egg nests, while others are still selecting suitable areas to settle down.
First, let's check in with each species of tern.
- Common Tern
A full clutch of Common Tern eggs on Rockabill – May 2024 (photo taken under NPWS license).
Defensive Common Terns.
- Roseate Tern
Roseate Tern pair sitting on a nest box (photo taken under NPWS license).
Roseate Tern sitting on eggs in an open nest (photo taken under NPWS license).
- Arctic tern
Arctic tern among the scurvygrass.
When we are not checking on the tern nests in our study sites, we are busy in ring reading. We are getting great use out of the 5 hides that we set up around the island. In the hides we can use the scopes and binoculars to read rings on as many birds as possible. By reading these rings we can gather information on the birds' origins, ages, nesting locations, mating patterns, changes in nesting success over time, and sometimes, their migration patterns when the same rings are spotted away from Rockabill.
We haven't forgotten about the other nesting seabirds spending the summer with us! Every day, we make sure to check on the Black Guillemot and Kittiwake breeding pairs, who have been just as busy as the terns, building nests and incubating eggs.
- Black Guillemot
Most Black Guillemot pairs have already started incubating their eggs. Black Guillemot eggs are much larger than tern eggs and have a purple- blueish hue to them. We have been finding Black Guillemot eggs in the nest boxes that we deployed under the helideck and to the south of the island but we have also been finding plenty of eggs in dark cavities all over the island. Black Guillemot parents incubate their eggs for longer periods than terns, with both parents typically sharing incubation duties for 28 to 32 days.
Black Guillemot on top of one of the 5 hides.
Black Guillemot egg in a wall cavity (photo taken under NPWS license).
- Kittiwake
Kittiwakes on their nests (photo taken under NPWS license).
- What's Next?
Rockablog: Preparing Rockabill Island for the 2024 season
Led by Project Manager Dr. Stephen Newton, the three Rockabill wardens have eagerly begun our NPWS-funded work on Rockabill and are very excited for what the season will bring. We have already been here for two weeks, and what a fortnight it has been!
In just 14 days, Rockabill has transformed into a hub of seabird activity. The island has gotten progressively noisier, resonating with the calls of black Guillemots and Kittiwakes, and now, of Common Terns, Arctic Terns, and Roseate Terns. Our days have been filled to the brim with preparations, ensuring that the island is primed and ready to accommodate the nesting needs of these birds.
Meet the Rockabill Wardens
Rockabill’s 2024 resident tern wardens- Emma (left), Kyle (middle), and Rochelle (right).
Rochelle Streker This is Rochelle’s first season as a warden on Rockabill, having moved to Ireland from the United States last year. Rochelle has lots of seabird and conservation experience all across America, including working with and surveying Black Skimmers, Wilson’s Plovers, Red Knots, Newell’s Shearwaters, American Oystercatchers, Marbled Murrelets, Bald Eagles, and many different species of terns. She has also completed a master’s in wildlife biology from Clemson University on the reproductive ecology of Brown Pelicans in the northern Gulf of Mexico. As she settles into her new Irish life in Dublin, she is looking forward to learning more about Irish conservation and having a great season out on Rockabill! Emma Roberts Emma, a newcomer to the Rockabill warden team, holds a zoology degree from the University of Galway and is nearing completion of her PhD focused on urban red squirrel ecology. During her time in Galway, Emma volunteered with the Galway and Claddagh Swan Rescue and devoted her time to rescuing and rehabilitating, injured birds, including feral pigeons, Woodpigeons, Mute Swans, Herring Gulls, Black-headed Gulls, Mallards, Grey Herons, and the occasional Guillemot! Emma, an enthusiastic bird watcher with a particular affinity for seabirds, is very excited to learn more about seabird conservation and kickstart her career with a season on Rockabill. Kyle Coughlan Kyle is a Dublin native and studied for his B.Sc. in Zoology and M.Sc. in Evolutionary Biology at UCD and returned to Ireland in April after nearly seven years abroad. Following university studies, he spent a year working with in the south of France with a group focused on the conservation of the European Roller. Then he worked towards at Ph.D. at the Jagiellonian University in Krakow where he studied Great Tits and Blue Tits in the forests of northern Poland. Having recently submitted his thesis he is very much looking forward to spending his first summer on Rockabill with the terns.Preparing the Island
After arriving at Rockabill on the 24th of April, the three of us and Steve quickly began preparing the island for the arrival of the Common, Roseate, and Arctic terns. Additionally, we've been observing the activity of the Black Guillemots and Kittiwakes that have already arrived on Rockabill and have begun searching for nesting sites. As the black guillemots are already on the island, we quickly began setting up nest boxes for them. These birds favour nesting in secluded, dark crevices within rocky formations. So far, we have set up black guillemot nest boxes beneath the Helipad, a preferred nesting spot for these birds, and on the rocks to the north of the island where we've observed pairs congregating.
Black Guillemot pairs checking out the nest boxes on the rocks to the north of the island (top) and under the helipad (bottom).
The main island is called the “Rock” and the smaller rocky island is called the “Bill”. While the Bill has very little vegetation, the Rock is covered in a densely growing plant called tree mallow. It takes up so much of the ground area on the island that there is no room for common, arctic, and roseate tern nests. Its swift removal was our next port of call. First, we removed the tree mallow from our study sites and then went about removing it from the remainder of the main island. We also had to organise our nest boxes for the Roseate Terns. The nest boxes were taken out of storage and organised by number from 00 to 948! Some of the boxes were broken or damaged during the last breeding season, so these boxes were repaired if feasible. Additionally, new boxes were constructed and labelled with ID numbers to fill any gaps. With a considerable number of nest boxes on hand, our aim is to maximize nesting opportunities for the roseate terns by deploying as many boxes as we can.
Roseate Tern nest boxes.
Next came the 5 hides, which are required to monitor the nesting terns without disturbing them. We assembled the hides at vantage points across the island. They were then weighed down with heavy rocks and tied down with rope in order to prevent them from being blown away in any storms. Luckily, we got the hides set up and secured in time for our first stormy day!
2 of the 5 hides set up around the main island.
On Saturday the 27th of April, we were visited by the Geological Society of Ireland, who spent a few hours on the island looking at Rockabill Granite. The members of the GSI were kind enough to help us remove tree mallow from various study sites. We really appreciated having more hands to help us with the removal! When the GSI left that evening, Steve joined them and headed back to the mainland. With Steve’s departure us wardens got busy setting up all of the Roseate Tern nest boxes around the island. First, we set up boxes around each of the assigned study sites, which can be monitored from the hides. Next, we started setting up the remainder of the nest boxes around the island. Aside from two stormy days with strong winds, rain, and high waves, we have been very lucky with the weather. A succession of clear days allowed us to finish setting up all of the nest boxes. Just in the nick of time too because this week- the terns arrived! First, the terns started circling the lighthouse in the AM. Every day they began flying lower and lower to the ground. Now, plenty of them have started landing on the island and looking for places to nest. We have spotted all 3 species of tern so far; Common Terns, Roseate Terns, and Arctic Terns. With their arrival, the island has gotten progressively noisier. We are very excited for them to start nesting so that we can continue to monitor them and start ring reading. And there you have it! Stay tuned for more updates as we navigate through the season's tern of events. - Emma, Rochelle, and Kyle This year’s work to protect and monitor the terns and other breeding seabirds on Rockabill would not be possible without the support from the National Parks and Wildlife Service and the cooperation of the Commissioners of Irish Lights.
