Today marks World Earth Day and in the current situation we find ourselves in a lot of people are turning to nature on a global scale to find solace and provide inspiration on their daily walks. To me no species on Ramsey says 'global' quite like the Manx shearwater. We always talk about 'our' Manxies and to some extent they are as over 90% of the world's population breed on islands around the UK coast. Wales is home to largest cohort with over 50% of that figure breeding here. Just 6 miles south of Ramsey lies Skomer island with the world's single largest population of 350,000 pairs. 2 miles further south is Skokholm, only a third of the size of Skomer yet home to 89,000 pairs, probably the densest colony in the world.
And yet the islands around Wales and UK only provide sanctuary to these birds for around 6-7 months of the year. They migrate during the northern hemisphere summer to the coast of Argentina, spending the whole time at sea around an area just south of where the Rio de la Plata meets the South Atlantic ocean. To get there they migrate via the coast of west Africa on the way out and up through the Gulf of Mexico before swinging across the North Atlantic on the return journey; a return trip of around 14,000 miles each year. Birds can live up to 30-40 years old meaning they could travel the equivalent of the moon and back 10 times in their lifetime!
Manx shearwater at sea off Ramsey (photo: G Morgan)
I blog about Manxies a lot on here ('we know!' I can hear you groan!) but I can't help it. They are a very special bird on Ramsey. Driven to near extinction by introduced brown rats their population crashed to just 850 pairs in 1998. Following the successful rat eradication the following year the population increased to 5,000 pairs by the last full survey in 2016. Due again in 2021 I am sure that figure will have increased further as I'm seeing signs of birds in areas that I know were previously empty.
Shearwaters are nocturnal on land, breeding deep underground in burrows. Their bodies are adapted for a life on the wing and under water. The trade off is long wings and webbed feet, set far back on their body, making them awkward and clumsy on land. Easy prey for the likes of great black-backed gulls if they were return by day. In fact we only see them in large numbers on the darkest of moonless nights. In order to monitor productivity, i.e. how many chicks per pair they raise each year (an important indicator of overall population health) and to allow us to attach miniature tracking devices that provide us with the evidence to help us further protect these birds when away from the safety of their nature reserve homes, we have a small colony of nest box burrows which allow easy access with minimal disturbance. At this time of year we are keeping track of who is back in which box and swapping tracking devices on birds as they return (doing the swap now means we can leave them in peace while they are incubating their single white egg).
Below is a short video of Box 20 - copious amounts of poo outside the box indicated the pair were back but they had only been returning at night and not staying in the burrow by day. To be sure they were back I set up a trail camera on in. As you can see, both birds are back again for the season. The camera operates using invisible Infrared light so although the images look like they are floodlight the whole thing took place in complete darkness (play video with sound on to hear birds calling overhead)
Brilliant video. Bever get bored of hearing about the manxies esp as we are so far away from them at the moment. Another great blog. Thank you