Posted 22nd Jun 2018 by Peter Byrne
For the first time in 20 years, the Manx shearwater is to be monitored on a remote Welsh island
The bird, well known for its daredevil flying stunts, will fly so low that it's wingtips will nearly touch the water. They are being counted on Middleholm Island off the Pembrokeshire coast in South Wales by National Trust rangers and volunteer researchers from the Wildlife Trust of South and West Wales (WTSWW).
The team employed some unusual techniques to conduct the count, as they played audio recordings of their call into their burrows and listening out for a response.
Together with Skomer and Skokholm, Pembrokeshire's islands are home to the world's largest breeding colonies of the Manx shearwater, with approximately 50 per cent of the global population there.
It is essential to monitor the Manx shearwater colony to assess their population health, with the effects of external factors such as climate change being measured on population numbers.
James Roden, National Trust area ranger for North Pembrokeshire, said: "For this year’s census we played the male and female calls of the Manx shearwater down individual burrows on an audio device. If a bird responded to the call then we recorded the burrow as active."
"This technique is used as the birds are in their burrows during the daytime, and usually fly at night."
Well adapted to a life at sea, the medium sized black and white bird has long, narrow wings and small feet that are tucked back on their bodies.
Breeding on Pembrokeshire's islands, the Manx shearwaters spend winter some 7,000 miles south off the coast of Argentina in the south Atlantic - some birds will complete this journey in less than a fortnight.
They will nest in burrows, mainly as they are unable to walk easily and will only move clumsily which makes them easy prey.
The surveying was a sensitive operation as Middleholm Island isn't usually open to the public - there are no paths nor easy access to the island with the team relying on a cliff-side scramble, a small boat and the weather.
Conducted by James and a team of five WTSWW volunteer researchers over one eight-hour day, the results are expected to be released this winter.
Image courtesy of Dave Boyle / National Trust Images