Among all the comings and goings at Ireland’s largest freight and passenger port, some tiny visitors are returning year after year.
Dublin Port’s colony of terns are “thriving”, according to BirdWatch Ireland, which has been researching and monitoring the birds with the support of the port for more than a decade.
“It’s incredible, they couldn’t be in a busier place,” explains Helen Boland, manager of the Dublin Bay Birds Project. “They’re right in the middle of Dublin city and right in the middle of a busy port.”
Two species of tern, the Common and Arctic, nest on four platforms in the port.
Two of the platforms are purpose-built pontoons – one off the Great South Wall and the other in the Tolka Estuary.
The pontoons are fitted with perimeter boards to protect the birds from predators.
“The numbers have been going up and up over the past few years – generally around 500-600 pairs. They are thriving,” Ms Boland says on her first visit to the pontoons this breeding season.
The terns have returned to the port having travelled vast distances over the course of the year.
Common Terns winter in West Africa, while Arctic Terns are considered to have the longest migration of all birds, moving from pole to pole.
Both species are amber-listed as birds of conservation concern in Ireland.
“Seabirds face all sorts of threats, including climate change,” Ms Boland explains. “For example, their normal breeding habitat of shingle beaches could be impacted by sea level rises and could be lost.
“That’s why it’s important to have areas like this. And now that we know they breed here, we need to make sure they are maintained and disturbances minimised, so they can keep thriving.”
Last year, avian flu had a significant impact on birds in the port, eliminating almost 20% of the breeding adult terns along with many chicks.
BirdWatch Ireland is working closely with the port to assess for any signs of it in the tern colony this year.
DPC Port Engineer Eamon McElroy said: “We are delighted to see the tern colonies arrive back to the Dublin Port pontoons, as they have done for at least 11 years now.
“Dublin Port Company is deeply committed to taking care of the environment in the port area in all its forms. This includes doing our part to preserve and enhance biodiversity.”
The ongoing partnership has enabled BirdWatch Ireland to compile a robust database of information on the port’s avian inhabitants.
“We’ve been ringing birds here since the early 1990s,” Ms Boland says.
“Among the returning birds last year was an Arctic Tern and a Common Tern that were ringed in 2000. That means those birds have potentially been coming to the port every year for the past 23 years, making them the oldest Common and Arctic Terns on record in the Republic of Ireland.
“So hopefully those birds have survived through to this year as well.”
