Over the years this blog has documented the devastating problems Ramsey’s burrow nesting seabirds faced when brown rats were accidentally introduced to the island via shipwrecks in the 1800’s. With eggs and defenceless chicks easy prey for this voracious alien predator a once thriving puffin colony became extinct, storm petrels disappeared and Manx shearwaters were severely impacted.
In 1999/2000 under the guidance of Wildlife Management International from New Zealand, the RSPB undertook an ambitious rat eradication programme, the biggest island to be tackled in the UK at the time. The success of this project paved the way for more recent eradications which the RSPB were involved in on Lundy, Scilly and, this year, The Shiants.
In 1998, the year before eradication, there were just 897 pairs of Manx shearwater breeding on Ramsey with very few chicks successfully fledging. In the first full survey after the rats had gone in 2007 this number had jumped to 2,387 pairs. By 2012 it had reached 3,835 pairs. Free from the pressure of marauding rats shearwaters were booming!
This year we undertook the next full survey and are delighted to announce the population has increased again! The figure now stands at 4,796 pairs – a 25% increase in 4 years.
Manx shearwater graph - rat eradication project took place in 1999/2000
With the rats gone Ramsey’s Manxies have been able to breed successfully, with ringed fledglings returning to breed on the island in their 4th or 5th year. The rapid increase has not been due to this alone however, with first time breeding birds from Skomer and Skokholm undoubtedly setting up home here too. To put the impact rats had on Ramsey into some context, our neighbouring islands have never had rats and between them account for nearly 50% of the entire world population of Manx shearwater with 316,000 pairs on Skomer and 38,000 on Skokholm.
Fledgling Manx shearwater on Ramsey - a very rare sight before the rat eradication
Ramsey’s remarkable population increase over the past 16 years means that Manx shearwater is now the most numerous breeding species on the island. Unfortunately very few visitors get to see one! Millions of years of evolution has produced a family of birds that breed in burrows on offshore islands free of ground predators, with a strategy of only coming ashore at night to avoid avain predators such as gulls. Long wings, for undertaking an epic migration to the coast of Argentina, coupled with legs set to the rear of the body to aid swimming makes for a top heavy, ungainly gait on land which would make them easy prey in they came ashore by day.
Surveying a species that nests underground and only comes ashore after dark is no easy task! The method involves playing a recording of the male and female ‘duetting’ call to a percentage of burrows on the island and knowing the total number of burrows you have to start with (yes we had to count them all!) .a correction factor is applied, worked out from a set of study burrows. With the help of a fancy formula we are then able to calculate an estimate of the total number of occupied burrows and thus breeding pairs
Click here to listen to the sound of a duetting pair of Manx shearwaters on Ramsey. The male is the higher pitched of the two
Sarah surveying shearwater burrows with Dewi!
Seeing Manxies
There is no overnight visitor accommodation on Ramsey but the neighbouring islands of Skomer and Skokholm provide self catering facilities to allow people to experience the unforgettable sight and sound of these mega colonies. For further information contact the Wildlife Trust of South and West Wales – make sure you pick a new moon period as far fewer birds come ashore on bright moonlit nights
If you are staying in the St David's area then a trip out to a coastal headland, like St David’s Head, on a summer’s evening with binoculars or telescope should reward you with the sight of thousands of birds streaming past as they return to the waters around the islands and gather in readiness for night fall. Even better you can go on an evening boat trip and get out amongst the Manxies – contact our RSPB contracted boat operator, Thousand Islands Expeditions, on 01437 721721 for more information
The Future
It is vitally important that Ramsey remains rat free. We have robust quarantine measures in place to try and prevent re-infestation not only by rats but any other alien ground predator such as house mice and hedgehogs. Visitors to the island will be aware of this as you will have been asked to search your bags for unwanted stowaways before setting foot on Ramsey! (it has happened elsewhere...)
Island restorations and the ongoing protection of breeding sites is only half the battle. Areas where shearwaters feed and migrate are of equal importance. Given the wide ranging nature of the Manx shearwater, capable of travelling to waters off the Isle of Man and back in a day to feed and spending 6 months of the year in the southern hemisphere, the need to adopt a robust network of Marine Protected Areas in the UK is an urgent priority. Maintaining strong links with our Birdlife partners and governments across the world is of crucial importance.
Seabirds are facing an uncertain future in the UK with severe declines seen in many species over the past 25 years. While this is a good news story for Manx shearwaters we mustn’t be complacent. The UK is responsible for around 90% of the entire world population of this species. Ongoing island restorations, quarantine plans, scientific research and political advocacy are all required to ensure this remarkable seabird continues to thrive.