Fersiwn Gymraeg ar gael yma

7,000-mile-long journey. From the coasts of Argentina to one of four Pembrokeshire islands. Over half the world population. In just under a fortnight.

Each spring, one of Wales’ most beloved visitors, the Manx shearwater, fulfils this outstanding journey from the coasts of Argentina in the south Atlantic to one of four Pembrokeshire islands – RSPB Ramsey Island, Skomer, Skokholm and Middleholm.

Now, thanks to recent monitoring work by The Wildlife Trust of South and West Wales (WTSWW), it’s been officially confirmed that the latter three Pembrokeshire islands are now home to more than 50% of the world’s entire Manx shearwater population - and this doesn’t even account for our very own RSPB Ramsey Island population!

It’s estimated that nearly a million breeding Manx shearwater adults reside on Skomer (350k pairs), Skokholm (89k pairs) and Middleholm (16k) based on the monitoring work by WTSWW, the National Trust and the University of Oxford and University of Gloucestershire. Whilst over on RSPB Ramsey Island, the count at the last full census in 2016 stood at just under 5,000 pairs.

The monitoring on Ramsey’s neighbouring islands required a careful approach as Manx shearwaters nest in burrows, meaning the monitoring team had to watch their footing to ensure minimum disturbance to the fragile nests.

The monitoring work involved playing the seabird’s social call into burrows across the three islands. If a bird responded to the call then the burrow was recorded as active as part of the survey.

In the past, RSPB Ramsey Island’s burrow-nesting seabirds, like Manx shearwater, suffered devastation when brown rats were accidentally introduced to the island via shipwrecks in the 1800s.

Back in 2000, an ambitious rat eradication project was carried out between RSPB Cymru and Wildlife Management International from New Zealand and paved the way for a dramatic recovery. The resilient Manx shearwaters managed to hang on during the rat-infested years thanks to overspill from the huge populations on the neighbouring Pembrokeshire islands. In 1998, the population was estimated at only 850 pairs – quite the different picture when compared to today!

Lately, our RSPB Ramsey Island staff have been busy building and digging over 100 nest boxes and fitting miniature tracking devices on the island’s breeding population. This will allow us to spy on the birds whilst they’re on the other side of the world.

For more information about the Wales population of Manx shearwater and their mammoth journey to and from their breeding grounds on Pembrokeshire’s islands, please contact ramsey.island@rspb.org.uk.

Image credits in order they appear: Lisa Morgan, RSPB Cymru, and Chris Gomersall, rspb-images.com