19 Dec 2024

Where do our seabirds spend Christmas?

Written by Liz Morgan, Seabird Ecologist

A puffin flying in the air, coming in to land.

While you are tucking into your Christmas pudding, have you ever wondered where our seabirds are spending the festive period?

Scotland is important globally for its large seabird colonies, supporting over 65% of the British and Irish seabird population. Around 1 million seabirds nest in areas cared for by the National Trust for Scotland, and our sites are some of the best places in Europe to see puffins, gannets and other seabirds. However, the bustling seabird cities at St Abb’s Head, St Kilda, Mingulay and the Treshnish Isles will be quiet at this time of year.

In winter, seabirds are no longer tied to their breeding colonies by hungry chicks demanding food, so they can travel far and wide ... and many do! Thanks to some detailed research and nifty tracking technology, we have a good idea where many species spend the winter, although there are still a few we know very little about.

Fitting birds with uniquely coded rings has been carried out at the Trust’s sites under licence as part of the British Trust for Ornithology’s (BTO) ringing scheme for many years by dedicated amateur ornithologists, researchers and our own teams. These rings give birds an individual identity so we can follow them throughout their lives.

A small metal ring is held between someone's finger and thumb. Numbers and letters are etched onto the ring.

Example of a unique coded metal ring, which was put on a puffin at St Kilda this year.

Spotting birds with rings (or making ring recoveries from dead birds) gives us a rough idea of where birds might spend their winter. There have been interesting historical reports from ringed birds at our sites:

The most extreme migration is made by Arctic terns who will travel from Scotland all the way to Antarctica and back every year!
Some recoveries of birds ringed at Fair Isle have been found in Togo, Namibia and Equatorial Guinea where they stopped off to rest on their long journey south.
A young puffin ringed on Fair Isle in 1958 was found alive in Plaistow (East London) in the winter of 1959, which is a very odd place for a puffin to be, as they usually spend their winter at sea in the mid-Atlantic. Perhaps the wee fella called in to pick up some last-minute gifts from Billingsgate Fish Market!
More recently in autumn 2020, our ranger at St Abb’s Head, Ciaran Hatsell, received a report of a great skua he had ringed whilst working on Fair Isle – it had been seen and photographed on Gooseberry Island, Canada. In general, great skuas spend their winter in warmer climes in the Bay of Biscay, around France, and off the Iberian coast near Portugal.

This year, as part of our efforts to look after species affected by avian flu, the Trust fitted coloured rings with unique ID codes to the legs of 4 adult great skua and 35 great skua chicks on St Kilda. We hope in the coming months and years that this will help us to find out more about where these birds are travelling to, if or when they return to St Kilda, and how long they live.

A large fluffy great skua chick lies on a patch of grass. It has a blue ring attached to one leg.

Technology has vastly enhanced our knowledge of seabird movements. Tracking devices are now small and light enough to be fitted to most birds and provide much more detailed information on winter locations. As a general rule, tags should be no more than 3% of the bird’s body weight, although ideally less than this to reduce the risk of negative effects from carrying a tag. Because of this, we are still not sure where some seabirds, like storm petrels, are spending their Christmas holidays!

Geolocators (devices which record light levels) have also been deployed as part of wider research projects on Trust sites, in particular by the Highland ringing group on Canna, the Treshnish Auk ringing group (TIARG), and the Fair Isle Bird Observatory. These devices can calculate a bird’s location by using the amount of daylight, the date and the time, to work out where in the world the bird is likely to be.

Geolocator results have shown that guillemots from Fair Isle tend to stick around in the North Sea for the winter, while birds from Treshnish go to the seas off North West Scotland and down to the French coast. Guillemots from Canna also go to seas off North West Scotland but some travel down to the tip of Cornwall [1]. In winter, kittiwakes might be out in the Western Atlantic off Greenland and Canada, around the southern North Sea, or even round to Portugal. Puffins are usually bobbing about in the middle of the North Atlantic; fulmars might be flying around south of Greenland, out in the Atlantic, or closer to home in the northern North Sea.

A young brown great skua soars above a clifftop. It has a blue ring on one leg.

An illustrated Christmas card featuring cartoon-like puffins swimming on the sea, with a Christmas-pudding-shaped ball floating beside them. The copy at the bottom reads: Festive greetings from the Mid-Atlantic.

SEATRACK, a collaborative study led by representatives from the Norwegian Polar Institute (NPI) and the Norwegian Institute for Nature Research (NINA), is mapping important seabird wintering areas and migration routes from birds at many locations including Trust sites. This is yielding new and important information needed for the management of seabirds in North Atlantic waters.

Find out more

The Trust’s seabird team is hoping to expand our knowledge further, with some exciting ringing and tracking work planned for 2025 and beyond. We hope to continue expanding our great skua colour-ringing work, which will help monitor how populations are (hopefully) recovering from the impacts of avian flu.

We are also looking to track fulmars and Manx shearwaters next year, with the hope that not only will this data shed more light on where birds are spending their time when they’re not at breeding sites, but it will also tell us more about their survival and help us identify potential threats at sea. The more we understand, the better position we will be in to help our seabird colonies thrive into the future.

Wherever our seabirds are, we hope they have a successful winter and we look forward to welcoming them as they return to our sites in summer for a productive breeding season.

Funding to help the Trust carry out vital work to protect Scotland’s seabirds is currently provided by the People’s Postcode Lottery via the Postcode Earth Trust, and generously supported by Tim and Kim Allan, members of the Trust’s Patrons’ Club.

References

[1] L Buckingham, M I Bogdanova, J A Green, R E Dunn and others (2022), ‘Interspecific variation in non-breeding aggregation: a multi-colony tracking study of two sympatric seabirds’, Mar Ecol Prog Ser 684:181–197

Ringing data reports included in this article come from the BTO: R A Robinson, D I Leech & J A Clark (2024), The Online Demography Report: Bird ringing and nest recording in Britain & Ireland in 2023, BTO, Thetford