Night has come to the island. Although the darkness is not absolute and will only last for a brief couple of hours at this time of year. The skies overhead are for once still. It is eerie not to see it filled with racing puffins, marauding gulls and pirating skuas. All are settled for the night, although you can still hear shuffling and the occasional call from the darkened rocks. Across this night landscape of island and sea cuts the bright white beam from the lighthouse, its light catching the tiny waves rippling in a calm sea.
Down at the landing, where concrete slabs and metal tramlines have been buckled and broken by relentless winter storms, the sea laps gently at the boulders and rocks. Through the darkness comes the mournful melody of seals singing.
Here we open three mist nets that have been set along what remains of the landing and the railway and then out onto the rocks. At its centre, where the nets meet, a large speaker plays the calls of our target species.
The sound that plays across the still night air is otherworldly, a rapid churring, chattering ter-chick, that ends with a trill and sounds like a purr. The call switches to another species, a ‘wuee-cha’ and spirited ‘chu-chattericha chu-chitteri’. From the blackness there is a response and a small black shape flutters overhead, briefly silhouetted against the dark sky before disappearing. Blink and you’d miss it. But the net does not.
Using the remaining ambient light we remove the little bird from the net mainly by touch and place it carefully in a bag. More birds fly into the nets and before long we have quite a few hanging from hooks around our necks. The team splits in two, with some staying by the nets to continue removing birds, while the others return to base to start the process of ringing them.
Back at camp the ‘jenny’ thrums in the background, powering lights within the tent where our ringing station is based. Out of the bag comes the first of the birds.
For a seabird, it is tiny. The size of a sparrow, with soft black feathers and a startling white rump. Black legs with tiny webbed feet dangle beneath it. Its small rounded head has a bright little black eye and a little hooked bill with a tiny tube on top, exactly the same as its giant cousins the albatross. The bird is a European storm-petrel.
The tube on top of the bill means the storm-petrel, along with fulmars, shearwaters and albatross, belong to a group called tube-noses. These birds drink seawater and excrete the excess salt through this enlarged gland.
At sea storm-petrels flutter over the waves, dangling their feet which patter over the water, and look like they are dancing. It is incredible that such a small, dainty and delicate looking bird can survive the rages of the ocean. It is not uncommon to catch a bird missing a foot or leg, but otherwise healthy, nibbled off by fish while they forage. And so here we have a hint as to their name… the name petrel is a reference to Saint Peter and given as they appear to walk on water. The name storm comes from their habit of hiding in the lee of ships during storms. Imagine it. You are a sailor, fisherman, merchant, out in the worst of storms. Seas raging, whipping spray from the tops of towering waves, streaming white foam. The boat is being thrown around like a toy. The dark clouds loom threateningly overhead, rain lashes down. Out in this wild, angry ocean you see the tiniest of birds, dancing among the waves. Emboldened by the wind they approach closer to the boats, and while they are certainly seen during calm weather, it is in such weather that they seem to be seen most often.
They come to Sule, like many other islands around the north and west coast of the UK, to breed and only return under the cover of darkness in order to avoid the attentions of gulls and skuas. They nest in crevices between and under rocks and on Sule they particularly like the wall of the disused railway. While walking along the path at night you can hear them purring from their burrows in the wall below your feet.
Once the bird has been ringed, measured and weighed we take it out of the tent and away from the lights. Under the black sky, where stars twinkle and the moon casts a shimmer over the ocean, and with the lighthouse looming darkly above, its clean light cutting a swathe through the night, we pause. Surrounded by the darkness we wait, letting the birds eyes adjust back to the blackness. They perch on the hand, wings flutter and then they lift off, a small dark shape briefly silhouetted against the sky before it disappears.
There are plenty more birds to process, and once we are complete we head back into the night, walk down the railway and back to the rocks to collect more birds from the nets.
And so to that second call on the tape lure. The ‘chu-chattericha chu-chitteri’ and ‘weecha’. This call is of a different species of petrel. Back on the rocks, waiting and watching for those little silhouettes to go into the net, occasionally a slightly bigger bird ghosts overhead, and a couple go into the net. Removing them in the darkness you can feel they are slightly bigger. Back at the tent and in the light, the petrel pulled out of the bag is more like the size of a starling. Like the European storm-petrel they are black with a white rump, although it is more V-shaped, and the tail is more forked. Most notably it has a greyish pale panel on the upper wing. This is the Leach’s storm-petrel. Leach’s do not breed on Sule Skerry, but can be found on islands such as North Rona. The tape has brought them briefly into the island.
In total in this night we catch 10 Leach’s storm-petrel’s and 120 European storm-petrels.
It is not long before the sky starts to lighten, turning from black to midnight blue. The shapes of the tents, lighthouse and rocky shoreline become more distinct. With the coming light the number of stormies caught slows right down as the birds head back out to sea. The shuffling on the rocks increases as birds start to wake, getting ready for the day ahead. For the ringers it is time to grab an early morning breakfast and a few zzzz’s before the activities of another day ringing and monitoring seabirds on the island of Sule Skerry starts again.