Jul 8, 2009

News from the cliffs

It seems that my life of late has involved walking up and down Marwick Head. It’s not so bad tho as at the moment we have auks and kittiwakes all sitting on eggs and young. The cliffs are sparsely populated but the undeniable fact is that there is some amount of successful breeding going on. To put it in a historical perspective as you probably know for the last six or seven years the breeding sea bird population has been struggling with in a group decline. Guillemots, razorbills, kittiwakes, puffins and all the terns have been having a hard time. The last couple of years have been little short of disasters with almost no young of any species raised.
Last year it was excruciating to watch. For weeks the weather was dry with no rain. The gulls colonised their grounds inland and started to lay but as the weather warmed and the fields dried their food source also began to dry up so within a matter of weeks the colonies one by one fell over and were deserted with what chicks that were hatched starved to death. As the fields and hillsides started to fill with aimless flocks of hungry gulls the news started to come in that Tern colony all over were starting to fail. This was due to there being no food. This time it was the sea that was the problem. Once again it was the sand eels that had disappeared. With in a couple of weeks virtually every single Tern colony had deserted what young there were had starved. All around Arctic and Common terns seemed to be loafing about scratching out a living and waiting until it was time to go. The last surviving group was out on the north western corner of the mainland at Skipi Geo. Here they probably clung on fishing Sile but as the sile moved away they were doomed and inevitably over they went. Things now got even grimmer. All around the coast the cliff birds were struggling but now the end had come. On the high cliffs along Orkneys west coast what few auks had young lost them. All the kittiwakes now quickly lost what few young they had leading to the desertion of the cliffs. Many moved inland to haunt strange places that you would never think to see them in better times. A strange and haunting emptiness hung over the whole place as birds loafed about waiting for their trigger to head away for the winter. Birders and locals alike walked around with heavy hearts. It was a truly terrible time.

So what’s been going on to cause it all?

Speculation and theories abound for the disappearance of the sand eel population but the most popular one certainly seems to involve the sea temperature. It works like this… In the winter there are good stocks of sand eels around us but as spring progresses the warm current that flows past us is getting progressively warmer as the years go by. The arrival of the warmer water deters the natural blooms of plankton that occur at this time of year. The sand eels rely on this bloom for their food at this time. As the colder water is pushed away their food goes with it, the fish migrate following the food. The waters empty of untold of thousands of tons of sand eel leaving little more than a desert behind them. The birds can only fly so far to follow the food so there is only one possible outcome.

This year is different tho. There is food about and things are moving along. All this is bucking the well established trend and no one really knows quite why. There’s an idea that the extended cold weather this winter has chilled the seas enough that the water reaching us is measurably cooler allowing the plankton to bloom. Consequently the sand eels have stayed put to provide the desperately needed food source. It’s a simple and elegant answer to a huge question. I don’t know if its right but it sounds good to me. What I do know is that there are birds on young all over. Whilst they may look sparse across the cliffs at least they are on young. Now all we have to do is cross our fingers because the toughest bit is yet to come. Looking today there were more Bonxies than I had ever seen ambushing returning auks, add to this the herring gulls, blackbacks and ravens taking advantage of the thinly spread numbers. Their next problem comes from this predation. With the ledges poorly occupied the cohesiveness off the colony is really put to the test. Its easier for a predator to get amongst the birds and take eggs or young if there is no fence of sharp bills to fend them off. So now it’s a matter of surviving this war of attrition until fledging. Fingers crossed we are going to have crop of young sea birds this year The cliffs look ok and smell even better. The Tern colonies are looking strong. The food just needs to hold out for a little while longer. I don’t really know how well the numbers compare to the good years but I suppose its not a lot more than ten percent or so. Its not huge but after year on year wipe outs it’s a glimmer of hope and success…

There is good news from Orkney…its not great news but it is good.

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