By Andy Hargreaves

The team from the RSPB undertaking the survey.

The team from the RSPB undertaking the survey.

A comprehensive survey of Scilly’s seabird populations got underway yesterday, starting on St Agnes and Gugh.

The two-month project will see researchers visit over fifty islands and rocks in the archipelago.

It’s been funded by the Seabird Recovery Project and manager Jaclyn Pearson says the work is long overdue – the last count was back in 2006.

Jaclyn says it’s important because that survey showed a fall in numbers. The team hope the populations might have stabilised although they fear that further decreases are likely, particularly for kittiwakes and herring gulls.

Jaclyn says the birds are affected by a number of factors, including over fishing in the areas they migrate to around the world, as well as climate change.

The team of three research assistants and twenty volunteers will be led by RSPB Officer Vickie Heaney.

Jaclyn says they’ll work in a similar way to police detectives at the scene of a murder – forming a line and crossing each island counting the number of chicks and eggs that they spot.

That works well for species like guillemots and razorbills, but some birds aren’t so easy to count.

Jaclyn says Fulmars tend to knock their eggs out of the nest if disturbed so need to be monitored through binoculars from a boat.

And the most difficult are Manx shearwaters and storm petrels – both of which nest underground. To count them, surveyors play a recording of the birds’ calls at possible nest entrances and listen for any replies from birds sitting on their eggs.

Many of the sites being visited are not normally open to the public, so they’ve had to obtain special permission from the Wildlife Trust.

The 2006 survey confirmed Scilly as being the most significant seabird colony in southwest England, supporting over 9,000 breeding pairs and one of only two breeding sites in the country for Manx shearwater and storm petrels.

Since then, the Seabird Recovery Project has managed to eradicate all rats on St Agnes. The rodents eat the seabirds’ eggs and it is hoped the work will allow bird numbers to recover.