Ultimate guide to sea birds
The UK coast has one of the richest breeding grounds in Europe, and there’s no better place to spot birds than from the cockpit of your boat, says Genevieve Leaper
Know your gannets from your gulls and your petrels from your fulmars
Sailors have been watching seabirds for thousands of years. Early navigators in the Pacific used their knowledge of how far different birds ranged from land to judge when they were approaching an island. The white tern was known as the ‘navigator’s best friend’. Birds carrying fish back for their young will even indicate the direction to follow. European sailors on long voyages also noticed the birds but often viewed them in a more superstitious light. It was good luck to see an albatross but bad luck to kill one.
These days we watch birds for pleasure rather than navigational cues; sailing and birdwatching go very well together – for a start there are usually binoculars to hand, and there is little effort involved – just keep your eyes open. By getting out to sea we encounter many birds that are difficult to see for the shore-based birder.
As a child, it was one of the things I loved about sailing, whether anchoring close to a clamorous colony of blackheaded gulls in a Solent harbour or the occasional sighting of a shearwater skimming the waves when we headed further west. Being a sailing birdwatcher led to working on surveys of seabird distribution at sea. The highlight was fieldwork around St Kilda in the breeding season, but I still enjoyed going to sea and watching birds after weeks of counting little but fulmars in the North Sea in the depths of winter.
UK birdlife
The UK’s productive waters are internationally important for seabirds, with almost half the European total breeding around our coasts. I didn’t fully appreciate how lucky we are until I sailed in the Mediterranean where there is nothing like the numbers or variety. We have 25 breeding species (not counting the sea ducks and divers) ranging from the familiar herring gull – the archetypal ‘seagull’ – to the elusive Leach’s petrel, which breeds on a few of the remotest Scottish islands, forages miles out at sea and only visits colonies by night. Several other species come to feed in our waters in winter or pass through on migration.
Although they belong to several different bird families, seabirds tend to have some characteristics in common. They are long-lived and slow to mature. Guillemots and razorbills can live 40 years, fulmars and shearwaters have reached 50 and some fulmars don’t start to breed until 20-years-old. Seabirds lay few eggs, often just one, and frequently pair for life.
There are some big differences too; British seabirds vary in size from the 3kg gannet to the sparrow-sized storm petrel weighing just 25g. Some spend quite a lot of time ashore and regularly roost on land. Herring gulls are equally at home following the plough for earthworms as following a fishing boat for discards. Others, like the shearwaters and petrels, are truly marine animals which only come ashore to breed and spend most of their lives out at sea.
There are coastal species which can be seen without even leaving the harbour. Birds will approach much closer to a boat than a person on shore so sitting in the cockpit at anchor can be the best way to enjoy close views of terns fishing, a cormorant drying its wings or a black guillemot swimming underwater. If you want to see rare petrels, head out to the edge of the continental shelf, but the majority of birds are found within the inshore waters where most of us sail. The best places are often where strong tidal currents concentrate their prey.
‘The majority of birds are found within the inshore waters where most of us sail. The best places are often where strong tidal currents concentrate their prey’
Breeding season spectacle
For sheer spectacle there is nothing like sailing past a big colony in the breeding season. Most seabirds choose to nest in inaccessible places such as steep cliffs and small islands so the sights, sounds and smells of tens or even hundreds of thousands of birds combine with some of the most dramatic scenery. The largest colonies are concentrated in the north and west, especially islands such as Shetland, Orkney, St Kilda and the Western Isles, Rathlin Island and the Pembrokeshire islands. Flamborough Head in Yorkshire is the largest mainland colony. But there are birds to be seen around all coasts and all times of year. The lesser black-backed gull is most abundant at Walney Island in Cumbria while the Solent and East Anglia hold some of the largest tern colonies. The South Coast is also the place to see the Mediterranean gull – a recent arrival to the UK. Some of our breeding birds fly south or disperse offshore at the end of the breeding season but then there are others arriving. Sooty shearwaters pass through from late summer on their return to breeding areas in the South Atlantic. Little auks move into the North Sea from the Arctic, along with a few glaucous and Iceland gulls.
Identifying seabirds
While it’s not difficult to find seabirds, identifying them can be tricky and a good field guide will be a worthwhile addition to any boat’s library. Most seabirds come in various combinations of black, white and grey, while skuas and juvenile gulls are brown. Colour is reserved for beaks and feet – most flamboyantly in that charismatic favourite, the puffin. Different groups can be told apart by body shape and flight characteristics but for closely related species we have to look for more subtle differences. Do the black wing tips have tiny white patches like fingernails? That will separate a common gull from a kittiwake. Common and Arctic terns both have red beaks, but the common tern’s beak has a black tip. Guillemot and razorbill can be hard to separate at a distance but close up the different beak shape is obvious.
To complicate matters, many birds look quite different in non-breeding plumage – guillemots and razorbills have much whiter faces, puffins lose their big colourful beaks. The black-headed gull (which actually has a chocolate brown face in summer) has a white head in winter. Not to mention the different plumages of juvenile birds. Gulls moult through several immature plumages and can confuse even experienced birders. Unlike many young gulls which look rather scruffy in their mottled brown plumage, the juvenile kittiwake, called a tarrock in Cornwall, has a smart black ‘M’ shape on its wings and is one of the prettiest seabirds. No wonder early naturalists thought it a separate species.
Plunging gannets
One bird that is easy to recognise is the gannet, the largest European seabird with a 1.8m wingspan and brilliant white plumage. The pale yellow head is not always obvious at sea but it has a distinctive shape in flight, very streamlined from long, dagger-like bill to pointed tail. Gannets also have an impressive feeding strategy, folding their wings back to plunge into the sea from heights of up to 30m. A diving gannet can hit the water at over 50 knots, the momentum taking it down to 15m or more where it also uses wings and feet to swim in pursuit of fish. Gannets have several adaptations including strong neck muscles, membranes to protect the eyes and a spongy bone plate at the base of the bill to cope with the impact. They take sizeable fish such as herring and mackerel and can be seen feeding with dolphins, no doubt taking advantage of fish chased to the surface. A fast swimming pod of common dolphins with gannets diving ahead of them is an unforgettable sight. More than half the world population breed in the UK, mostly in Scotland. The Bass Rock in the Firth of Forth is the largest gannetry in the world. Clyde sailors can also enjoy the local gannetry at Ailsa Craig and there is even a small colony in the Channel Islands.
Fulmar sense of smell
The fulmar is the closest we have to an albatross. Although its grey and white colouring is similar to a gull, the fulmar has a very different style of flight, fast and efficient with wings held straight. The head shape is also unlike a gull with tubular nostrils on top of the beak. Along with the other tubenoses (albatrosses, shearwaters and petrels) fulmars have a good sense of smell – unusual in birds – which they use to locate food and possibly for navigation. Fulmars have shown a phenomenal increase in range over last 200 years. Until the mid-18th century, this species only bred on St Kilda and Iceland; now they nest all round the British Isles. Human activities have probably contributed to the fulmar’s success, with whaling then fishing providing vast quantities of offal and discarded fish. I’ve counted flocks thousands-strong following trawlers in the North Sea.
Burrowing shearwaters
Shearwaters are well named, the tips of their long narrow wings almost brushing the water as they soar the waves. On a perfectly calm day I have even seen shearwaters soaring the wash of a large motoryacht. Perfectly adapted for long distance flight, they are clumsy and vulnerable on land and nest in burrows. Shearwater colonies are restricted to the western seaboard, totalling 80% of the global population and including the largest colonies in the world on the Isle
of Rum and Skomer in Wales. Manx shearwaters leave our waters after the breeding season, migrating to the rich fishing grounds off Patagonia. Like the early European navigators they use the prevailing winds, following the west coast of Europe and Africa then taking advantage of the trade winds to cross the Atlantic to Brazil. Taking a different route on the way back they use the westerlies to cross from the Caribbean. A male from Skomer flew 4,800 miles south in 6.5 days. How do we know? The first clues about the travels of individual birds came from the occasional recovery (often once they were dead) of birds that had been ringed. But recent advances in technology have enabled researchers to fit even the smallest seabirds with a whole range of dive recorders, geolocators and GPS loggers, revealing their lives at sea in fascinating detail.
Storm petrels
Bird numbers are generally low in the open ocean but I remember a passage from the Azores to Ireland when the storm petrels lived up to their name; for three days of gales we were surrounded by ‘stormies’ fluttering low over the foam streaked sea, completely at home in the huge swells. Around Scotland I have mostly seen these diminutive birds in exactly the opposite conditions. They feed on zooplankton by pattering the surface with their feet and perhaps an oily calm is also good for feeding.
Bold herring gulls
Have you ever wondered whether it is the same herring gull that always perches on your dinghy in a particular anchorage? It might well be. Herring gulls take a wide variety of food and can be found foraging from sea to shore to refuse tip, but individuals may specialise in where and what they eat. While some make a habit of following fishing boats, I think there are yacht specialists too. For several years, whenever I visited Canna harbour in the Hebrides, a particularly bold gull would soon arrive onboard. I could recognise Henry, as I called him, by the pattern of black flecks in his yellow eyes – it wasn’t difficult to get close up photos of a bird who would join us in the cockpit.
Tern migration
Not everyone loves gulls, but their relatives the terns are generally more admired and have been called sea swallows. They feed in shallow coastal waters, hovering and swooping down to catch fish at the surface. Terns don’t like to sit on the water; out at sea they will often perch on driftwood or buoys. Common, sandwich, and little terns all breed around the Solent and Poole harbour. Their preference for flat ground, such as sand or shingle beaches makes them vulnerable to rising sea levels and disturbance. Only the Arctic tern is more abundant in the north. These beautiful birds spend more of their lives in daylight than any other creature by making an epic migration from Scotland and further north to the Antarctic for a second summer.
Amazing auks
If the fulmar is the closest we have to an albatross, the auks are the northern hemisphere equivalent of penguins, although they are not related. Penguins hold the deep diving records but guillemots can descend to 180m. Like the penguins, the great auk gave up flight entirely – and was hunted to extinction in the 19th century. The surviving auks have compromised; their short wings are best suited for swimming underwater but they can still fly – most of the time. Guillemots and razorbill chicks jump from the breeding ledges when only a third of adult size with tiny, ineffectual wings. At the same time the adults moult their flight feathers all at once so for a few weeks around August the population is flightless.
The puffin, most recognisable and probably best-loved of our seabirds, is also an auk. Despite those bright conspicuous beaks, puffins can be surprisingly hard to spot at sea. They are small and spend even more time underwater than other auks. While a guillemot will carry a single fish back to feed its chick, puffins are well known for their ability to hold a whole beakful of sandeels – one was recorded with an incredible 126 fish. All the auks are most abundant in the north and west but there are small puffin colonies on the Channel Islands, Isles of Scilly and Portland Bill so you might see one in the Channel.
Population decline
When I started working on seabirds in the late 1980s, most species were doing well, but sadly the last few decades have seen an alarming reversal in fortune. As elsewhere, many seabird populations are declining, some drastically. We have lost around half the kittiwake population since 2000 and even the adaptable herring gull is in trouble. Arctic skua and lesser black-backed gull have suffered the steepest declines and the puffin was recently added to the ‘red list’ of Birds of Conservation Concern as globally threatened. Birds which feed on sandeels have been particularly badly hit, probably due to a combination of overfishing and warmer seas affecting the sandeels’ planktonic prey. Climate change will undoubtedly have multiple impacts on marine ecosystems. At sea, birds are accidentally caught in fishing gear and vulnerable to oil pollution and the ever increasing tide of plastic. Introduced predators can have a devastating effect on island colonies, though there have been some successful rat eradication projects. Disturbance can also be a problem so please be careful not to approach too close whether afloat or ashore.
We all hope the puffin won’t go the same way as the great auk, but enjoy the birds while you can. If you keep a good watch, you never know what might fly by – last summer a black-browed albatross turned up among the gannets at Bempton cliffs!