The Dale Princess leaves Martin’s Haven at 7pm, with up to 30 passengers, a guide, and two crew.   A crew member gives a safety briefing as we leave the jetty – ending with ‘your emergency exits are  . . . . . ‘ as he points in all directions except down.  We pass Marloes Deer Park – a promontory walled off in the 18th century in anticipation of keeping deer there, but the deer never arrived.  The National Trust look after it now, managing the grazing to provide short turf for chough to probe into for leather-jackets and other mini-beasts.

Beyond the Deer Park, the water opens out.  To the south is Jack Sound, a fast-flowing channel of water with rocks sticking out at low tide.  Many a boat has foundered here in the past.  A ridge of rock underwater causes quite a lot of rough water when the tide is running. 

Cormorants sit on the rocks, and ‘holding their wings out to dry’ – not so much their wings as their body feathers which aren’t very waterproof, and need to dry between fishing trips just to keep the birds warm.  If having non-waterproof feathers seems odd for a waterbird, it actually means they don’t keep so much air in their feathers when they dive, they aren’t so buoyant, so making it easier stay underwater to chase fish. The disadvantage is that they get waterlogged and cold after about 15 minutes.  Someone asks about the difference between cormorants and shags – shags are smaller, sleeker, blacker, narrower bill, and no pale patch on the throat (though young birds are paler on the underside, and a bit more difficult to separate without a good view).

Now we are seeing auks as well.  Puffins, razorbills and guillemots sit on the water or fly past, often coming in low and close.  The differences are obvious in close-up – puffins with their multi-coloured bill and orange feet, razorbills are black and white with a large beak the shape of an old-fashioned cut-throat razor, while guillemots are brown and white with pointed bills.  Questions come non-stop from the passengers, and they learn that seabirds are long-lived – thirty or forty years or more, don’t breed until they are several years old, mate for life, and only have one egg per year.  But they might get divorced!  If they have a couple of failed breeding seasons, perhaps it’s better to try with a new partner next time.  Puffins breed in burrows, razorbills nest on small ledges and in rock crevices, while guillemots believe in safety in numbers, choosing ledges where they can mass in their hundreds. 

We chug along the ‘Neck’, the bit of Skomer Island with no human interference, look through the Lantern – a cave that runs underneath the island and out the other side, then the boat slows so we can hear the kittiwakes calling – kitti-wa-ake – at a small colony low on the cliffs.  These small and pretty gulls are hanging on here, despite having virtually disappeared from the Pembrokeshire mainland, and from other colonies further north.

Sometimes this journey throws up a real gem, and back in 1996  the skipper saw a couple of fins in the water just about here.  We went to investigate, and realised it was a fifteen-foot basking shark – just a young one really – and we were looking at the back fin and tail fin, and the shadow of its body under the water.  The boat got quite close before the shark dived.  It came up again a few yards away, but soon went under again and disappeared.    Basking sharks often come up through the Irish Sea, but mostly they are on the Irish side.  Probably less than one a year is seen on the Welsh side, and this is the only one I saw in twenty years of guiding these trips.

The Princess moves into North Haven and the skipper cuts the engine.  The silence is wonderful!  The steep grassy slopes are seabird cities.  Rock ledges crammed with guillemots. Thousands of burrows, each with a puffin standing outside.  Yet there are still enough puffins to form a flying wheel – they fly circuits, apparently each bird more or less level with its burrow, and all the time birds are joining the wheel while others drop out and head for their burrows.  Then you begin to realise it isn’t really silent.  Apart from the whirr of countless wings (beating up to ten times per second), there are growls of puffins, gargles from guillemots and razorbills, the raucous cries of gulls, and even the songs of wrens nesting in scrub on the cliffs. 

The relative quiet makes it easier to talk about the history of this island, 2-5000 years of human occupation, and farming that continued until the early 20th century.  It has been a nature reserve since 1960, owned by the Natural Resources Wales (successor to the Nature Conservancy Council and the Countryside Council for Wales), is managed by a committee that includes various local organisations, and is administered by the Wildlife Trust for South and West Wales.

The boat engines start up again, and the journey continues along the north coast of the island, stopping at the Garland Stone so we can appreciate the grey seals – come August, they will start dropping their pups on the beaches here and about 250 will be born by the end of the year.  

If the seabirds haven’t been spectacular enough so far, the real adventure is about to begin.  The skipper steers away from Skomer, and out into the open sea of St Bride’s Bay.  We aren’t going far out – keeping well within sight of land.  But now is time to keep our eyes peeled.  There is a good chance of porpoises – small dolphins that don’t really show much of themselves except a fin as they surface to breathe.  And just maybe there will be a pod of common dolphins – more rarely something really special such as a bottlenose dolphin or even a Risso’s dolphin.  But what we are really here to see are the Manx shearwaters.

Manx shearwaters are medium-sized relatives of albatrosses, and the Pembrokeshire Islands (Skomer, Skokholm and Ramsey) are home to about 400,000 pairs, or about half of the known world population.  They are the most numerous bird species breeding on Skomer, but the chances of seeing one alive during the day are slim.  They are very clumsy on land, and in order to evade predators (large gulls mostly) they nest in burrows and come to land only at night when the gulls are asleep.  On most nights, a few birds get caught out at dusk or dawn, or by moonlight, and the island is littered with corpses, testimony to the success of the gulls.  The numbers killed are, however, a minute proportion of the total population.  So the best way to see them is on a boat trip like this in the evening when the birds come back from the feeding grounds and form vast ‘rafts’ floating on the water, waiting for it to get dark.  The Manx part of their name is because the first ones to be described scientifically were taken from the Calf of Man – a small seabird island on the southern tip of the Isle of Man in the middle of the Irish Sea.  Few live there now, because that island became overrun with rats, which predate ground- and burrow-nesting birds.

Anyway, we start to see small parties of shearwaters on the water and the skipper steers towards them.  They are flighty at first, especially if the numbers are small.  On some trips we see only a few dozen, but on a good night, usually in June and July, there can be thousands, even tens of thousands.  One parent will be out on an extended fishing trip – perhaps for three or four days – before returning to the nest with food for the chick.  The other parent will be with the egg or the chick (at least for a few days after it hatches) and then will go on short fishing trips.  So on any night, up to a fifth of the population could be waiting to come ashore.

Although they are black and white, like many other seabirds, they are quite distinctive with their long straight wings, gliding over the water surface, taking lift from the slightest breeze and from air currents over the waves.  A flock seems to move as one all showing their black uppersides, then turning to show their white undersides, then back again.  They fly so low that their wing tips seem to touch (shear) the water surface. They flap only when they have to, and this energetically economical form of flying means they can cover vast distances quite rapidly with very little effort.

As the numbers build up, the birds fly close to the boat, even those on the sea may allow the boat to drift in closer.  Care is taken to avoid extra disturbance – this is an internationally important population of this species.  Having heard about the habits of these birds, the passengers start firing more questions -how long do they live (the oldest known individual was at least 55 when last seen), how far do they travel (down to the coast of Argentina), where else do they live (the Calf of Man, Rhum in the Scottish Hebrides, on some of the islands around the coast of Ireland, Iceland, and a few are even in the mountains on Madeira – see here for a full map. )  What do they eat (small fish, squid, other small sea creatures that they catch underwater having dived from the surface.)

How do they find their burrows in the dark?  Come to that, how do they find their island homes when out in the middle of the ocean?  Like any migrating birds, they seem to have a built-in compass, but also an acute sense of smell that picks up the scents on the air currents helping them home in on the colony.

During the day, the birds are pretty silent – we rarely hear anything from the boat – but as it gets dark, and they fly to their burrows, it gets very noisy.  They have a very raucous call (listen here), with a rhythm a bit like ‘a cup of caawwfeee’, which is individual to each bird.  We can tell the difference between male and female calls, but they can tell the difference between individuals.  So as they get closer to their burrows they are listening out for answering calls from their mates or chicks.  The noise is so incredible that the Vikings refused to land on some islands because they thought they must be haunted.

Are they affected by oil spills?  Now there is a question!  The last big oil spill here was the Sea Empress in 1996.  Fortunately for our seabirds, this spill happened in February, before the birds returned to islands to breed.  Otherwise, they would have been sitting ducks – floating on the surfaces amid the oil, diving down and coming up through it, feeding on fish that may have been affected – the oil would have destroyed the air-trapping features of the feathers, so the birds would have got cold and waterlogged and died – as nearly 5000 others did, birds (mainly common scoter) that were wintering in the area.

There are more general questions about the area, the island, and the seabirds.  Then one young lad put his hand up. When are we going back? There was a shocked silence at his temerity.  Fortunately, he could be reassured that we were already heading back to Martin’s Haven – the evening was getting decidedly chilly.  I welcome the short but steep walk back to the car park – a chance to get the body moving and warmed up after two hours of sitting still on the boat.

The Seabird Spectacular cruises can be booked on-line through Dale Sailing, and run several times a week (depending on suitable weather) from May to July. By the end of July, most of the puffins, razorbills and guillemots have gone out to sea for the winter.

In August and September, Dale Sailing run a different Pembrokeshire Islands Safari on a fast boat (protective clothing provided) that includes Grassholm Island where there are nearly 40,000 gannets nesting.

If you are staying in the St Davids area of Pembrokeshire, Thousand Islands also run similar seabird trips, though I have no experience of them.

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