Life as a Skokholm Island Volunteer : Part 1

July 17, 2019

In February I applied for a position as a long term volunteer on Skokholm Island in Pembrokeshire, South Wales. Having applied for positions on neighbouring Skomer Island and being unsuccessful I was ecstatic when I was offered the job, and spent the next four months dreaming of seabirds and an isolated island life. After lots of preparation and a hurried weekend buying all the food I’d need for my 3 months away, I finally arrived last Monday. This post is an update of what I’ve been doing over the past two weeks. 

Skokholm was founded as the UK’s first bird observatory in 1933 by Ronald Lockley, who bought the island after falling in love with it, and it has a long and colourful history. Reading one of his books “The Island”, he tells how in 1934 on the knoll opposite my bedroom window, the ex-king Ferdinand of Bulgaria, a keen birder, sat on an armchair and was brought a manx shearwater chick named ‘Hoofti V’ to examine. He had come as part of the 8th International Ornithological Congress being hosted on the island, and 200 people were escorted to it by two Royal Navy destroyers! 

‘Hoofti V’ was part of a group of birds that Lockley had been studying to gain an insight into their life histories. An avid naturalist and prolific writer, he pioneered long term studies of the seabirds on the island and wrote about them. Skokholm’s records and monitoring work go back 90 years, and it is to this huge body of work that I will be making a small contribution. 

During the time we are not working I am free to explore the island, and something new can be found each time. Seals float idly in the bays, dolphins and porpoises can be spied just off shore, as well as gannets from nearby Grassholm. A wide variety of other birds pass through on their way elsewhere, and just occasionally something rare for Skokholm’s bird list, which currently stands at 299! 

Apart from a few domestic and maintenance duties, such as changing the compostable toilet bags, cleaning on guest changeover days, and clearing paths, we are at work ringing and monitoring the birds that call the island home. 

Fulmars are monitored for productivity at six spots around the island, and whilst it can be hard to tell when they are incubating eggs, the chicks are now appearing thick and fast. Soon the fulmar chicks can be left by themselves, and although they look vulnerable, they have a secret weapon. They can projectile vomit an oily substance onto any predator, effectively gumming up its feathers, which can potentially mean death.

Guillemots and razorbills, which only a month ago clambered around the cliffs in their thousands, have dwindled almost to nothing. A few chicks are left to make the twilight jump down to the sea, their parents encouraging them down. 

The puffins have had an extremely early breeding season this year but luckily they are still around in their thousands, although perhaps not for much longer. Each evening they gather on the cliffs, nodding their heads in synchrony, a sign that it's nearly time to go.

Great and lesser black-backed gulls stalk amongst the burrows, waiting for a chance to steal some fish or snatch a young puffling.

One of our tasks is to read the colour rings which are attached to the legs of some of the puffins which helps us to identify them as individuals and so work out their survival rates. We also conducted a 24 hour ‘puffin watch’ to study rates of kleptoparasitism within a study plot of burrows. Kleptoparasitism is where an animal feeds by stealing food caught by another and is exhibited by certain gulls on the island. We noted how many puffins delivered fish to their burrows as well as how many gulls succeeded in snatching fish off of them. Though the overall percentage of thefts is low, it appears to be a successful strategy for some gulls. 

At night the island comes alive in a different way, and on dark nights manx shearwaters arrive in their thousands. At first you hear them at a distance, their eiree cries and howls coming ever nearer. Next you hear the swoosh of their wings above you as they slice through the air, until they crash down into the undergrowth somewhere near you. There they lay in a daze for a few minutes, until they gather themselves, get their bearings, and scurry clumsily off to their burrows. 

We also monitor the storm petrel, a tiny seabird which nests in rocky crevices. As it only comes back to the island at night, is sensitive to disturbance, and burrows in relatively inaccessible places, it is quite difficult to monitor. At night sometimes the guests are taken down to the Quarry to watch them flutter around like bats using an infrared camera.

We play back storm petrel calls into potential nest sites to elicit a response from one of the pair that would be in the burrow during the day. The other partner is out at sea at this time. Once the recording is played into a crevice, the bird will sometimes respond with a “terr-chick” sound or a purr or both. This is done in certain specific plots over a number of visits, and the rate of responses is then used to estimate population size over the whole island. If, for example, around 35% of birds responded in the plots, we know that when the whole island is surveyed only 35% of the birds present will respond. We can therefore extrapolate to get a rough estimate of the total population of breeding storm petrels.

There have been so many amazing experiences already, and over the next few weeks we will be checking on the progress of the manx shearwater chicks, and ringing manx adults and storm petrels. We have also started digging in prototype wheatear nest boxes, and migrating birds will soon be passing through. Watch this space!

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