Boaters are being asked to do their part to protect the nesting sites of the common tern — the critically endangered cousin of the Bermuda longtail.

A government spokeswoman said that there are only five nesting pairs in Bermuda, who lay clutches of three eggs in nests on tiny islets or ship buoys.

“Jet skiers, paddle boarders, kayakers and other pleasure boaters are asked to avoid landing at nesting sites and to refrain from mooring to ship buoys with nests to allow the common tern population a chance to increase,” the spokeswoman said.

“Nesting sites are marked with ‘No Landing’ signs. If disturbed, any chicks that fall into the water will drown. In addition, adult birds frequently swoop down on intruders as a warning to leave the nest area.

“Two nesting pairs have chosen ship buoys, one pair is on the buoy near Morgan’s Point in the west end, and the other pair on the buoy in St George’s Harbour.”

Mark Outerbridge, senior biodiversity officer at the Ministry of Environment, said: “Sadly, we are looking at a very unpredictable future for Bermuda’s nesting tern population. We trust that the boating public, once aware of the plight of our terns, will be extra sensitive to the nests.”

David Wingate, retired conservation officer, has been monitoring the population as a volunteer and has also appealed for public co-operation in protecting the five remaining nesting pairs.

Bermuda’s endemic common tern is unique to the island as it shares no genetic contribution from terns found elsewhere on the globe.

Common terns fall under the Protected Species Act, which provides for a maximum fine of $25,000 or imprisonment for anyone convicted of causing deliberate harm to the species.