Rare tern returns to Bermuda but breeding hopes are dashed
A rare cousin of Bermuda’s iconic longtail returned to the island last year – but neither of the eggs known to have been laid successfully hatched.
Miguel Mejias said in the latest edition of the Bermuda Audubon Society newsletter that at least four roseate terns were spotted in Bermuda in the summer – including two that were previously tagged on the island. A clutch with two eggs was discovered on an islet in the Great Sound.
“Unfortunately, the two-egg clutch did not hatch, most likely due to infertility,” Dr Mejias said.
“We are hopeful that the roseate pair safely return and successfully produce young in 2023.”
The roseate tern was once common in the island but the species was wiped out in Bermuda by hunters and specimen collectors in the 1870s.
However, in 2018 the Bermuda Audubon Society confirmed that a pair had successfully nested and hatched a single egg.
While the birds were initially believed to have travelled to the island from the Caribbean, Dr Mejias said that based on their size it was now suspected they might have come from the northeastern roseate tern population, which breed along the coast of Massachusetts, Maine and Nova Scotia.
He added that genetic testing would be needed to confirm if this was the case.
Dr Mejias said that in May this year two roseate terns were spotted by Trevor Rawson of the Bermuda Zoological Society in the Harrington Sound area.
“Interestingly, one of the birds had metal bands on both legs, which is how we band our chicks in Bermuda,” Dr Mejias said.
“This was the first confirmation of recruitment for our Bermudian roseate terns. Unfortunately, neither roseate tern was seen again in Harrington Sound.”
Later that month, Dr Mejias and Erich Hetzel spotted three roseate terns in Mangrove Bay and four of the birds were spotted on an islet in the Great Sound on June 22, where the clutch was later found.
Another tern species rare to Bermuda, the common tern, was also spotted in Bermuda during the breeding season.
Nine birds were seen over the course of the season along with two clutches of eggs, one clutch was found to be infertile.
Three chicks hatched from the second clutch, found in St George’s, and were carefully monitored by Dr Mejias over the following weeks.
“Unfortunately, I found the ‘runt’ of the brood dead on July 2,” he said. “On July 13, accompanied this time by Neal Morris, I fitted both chicks with uniquely numbered leg bands and a plastic green band for individual recognition from afar.
“My father and I witnessed the fledging of both banded chicks on July 26. By August 6, the banded fledglings were often seen being fed by adults near Stone Crusher Corner, about 3km from their nesting site.”
Dr Mejias said that both birds were spotted in Harrington Sound on September 22, the day before Hurricane Fiona passed the island.
“The day after the storm, Peter Adhemar spotted one of the banded juveniles in Harrington Sound, this time, however, with 15 common terns; most of these were undoubtedly migrants brought in by Fiona,” he said.
“Although we were only able to confirm the presence of one of two tern chicks, I am hopeful both birds, as well as their parent, survived the storm together.”