First common tern chicks return to Mayo lake after 86- year absence

MAYO has waited 75 years for the return of Sam Maguire and Lough Carra has waited over 86 years to see the return of common terns fledging chicks on the lake.

In one brilliant summer for Mayo, the All-Ireland football title and a successful breeding season for a pair of Lough Carra common terns have returned.

This conservation success story is made all the more incredible by the fact that in the first year that a tern raft was deployed on the lake, all three tern chicks successfully fledged the nest and are currently preparing for their amazing migration to sub-Saharan Africa.

The common tern, Sterna hirundo, is one of five breeding tern species that nest and breed in Ireland over the summer months.

Although they have been recorded visiting Lough Carra regularly over the last number of years there have been no confirmed records of breeding pairs that have successfully fledged* chicks on the lake since prior to 1940.

This is largely due to the lack of suitable nesting sites where these ground nesting birds are protected from predators.

The invasive American mink has been a particular problem for ground nesting birds since its introduction to Ireland for fur farming in the 1950s.

This is because many native birds have no natural defences against this opportunistic semi aquatic predator that can swim out to small islands where many birds would naturally nest.

Inspired by the success of tern rafts in Lough Atalia in Galway city, where Conservation Volunteers Galway and ATU have been constructing and managing rafts for the last seven years, the NPWS attempted to help this amber listed bird in Lough Carra by installing a tern raft on the lake.

Funding for the raft was provided by the NPWS and two of the Mayo rangers, Brian Hughes and Sean Harrison, were assisted in the project by the LCCA and a group of local volunteers, Pádraig Farrell, Nuala Irwin and Michael Kingdon.

Based on the designs for the rafts in Galway city they built a predator-proof raft out of recycled plastic and perspex, with a gravel base to mimic the natural nesting habitat for terns which would be on pebble shores or beaches.

It also included a caller to play tern calls to attract terns to the raft along with some small wooden shelters to protect the birds in hot weather and from attacks by gulls.

The raft was put out in the lake in early April, attached to an anchor to hold it in place, and within a few days a few common terns were spotted flying around the raft to assess its potential as a nesting site.

Brian Hughes explained that having the tern caller on the raft to play their calls really helped bring the birds into the raft.

Terns naturally prefer to nest in colonies as it can provide safety in numbers so they are attracted to the sounds of other terns calling.

Soon after one pair of terns began nesting and they fledged three chicks in their first year breeding on Lough Carra.

This is an amazing achievement after such a long absence.

In his book Birds of Counties Galway and Mayo, R.F. Ruttledge described large numbers of terns nesting on Loughs Carra and Mask up to about 1920 but the numbers decreased and breeding stopped on Lough Carra prior to 1940 while a few continued on Lough Mask.

This project marks the first confirmed record of terns successfully fledging chicks on the lake in over 86 years so it is incredible to have all three chicks fledge successfully and it is really important for Ireland's common tern population.

The chicks will spend the rest of the summer here in Ireland before they undertake their first migration down to sub-Saharan Africa for the winter.

If you are visiting Lough Carra in the summer months keep an eye out for these elegant streamlined birds flying over the lake.

As for the project, it will continue next year and Brian hopes we will see more terns nesting there in 2027. If this year’s pair return again their presence on the raft should help attract other terns to hopefully establish a colony.

Further down the line this project could consist of the exciting prospect of several tern rafts on the lake to ensure there is a sizeable breeding population present here.

This will help protect the long-term viability of the local tern population.

* Fledge: To feed and care for (a young bird) until it is able to fly. (Collins English dictionary).

Although terns have been observed to nest and attempt to raise chicks on Lough Carra since the 1940s, there are no confirmed records of the chicks successfully fledging up until this year.