The arrival of the guillemots took many frequenters of the east coast shoreline by surprise this year. These are relatively unfamiliar visitors, wary of coming too close to humans, yet here they were, far from their normal feeding grounds, some of them even paddling, unusually, up rivers. Worse still was the dead bodies and sick birds found on the sands. One birdwatcher on Leven beach in Fife reported finding 23 of the birds dead, and the beach “covered with feathers”. A thousand guillemots, according to news reports, have been found dead on the coast of Scotland, as well as many razorbills, but why?
Various possibilities were proposed, bird flu being one of them – but when birds were tested for the virus the results were negative. What was striking though was how emaciated the birds were. Many weighed half their normal body weight of just over a kilogram. Researchers at the Centre for Ecology and Hydrology have confirmed that the birds had indeed died of starvation. As Dr Francis Daunt, seabird ecologist at the centre, has put it, “these birds seem desperate. They are calling, sitting on the river shore, not really doing anything because they are probably starving and they’re not able to find food”.
So, the problem is not enough food source? The fish population, on which they depend, has been overfished, or declined?
That theory has been proposed by some, particularly given there is a fishery around sandeels, but it doesn’t seem to be what the experts are going for – even though, as Daunt puts it, “the most logical explanation is that there is a problem with their food supply”.
A theory, suggested by satellite oceanographer Peter Miller, that the problem may be linked to an algal bloom off north-east Scotland that may contain harmful or toxic species, is currently favoured. Corpses of birds are being analysed, their stomach contents, liver and kidneys tested for toxins in a lab.
One of the reasons this theory is being taken so seriously is the fact the deaths have only occurred in two bird species – and that, as Daunt describes, “the effects of toxins are species specific”.
RSPB Scotland has also said that the algal bloom off the north-east coast is close to some key seabird feeding hotspots, and beached birds may have been feeding there and picking up algal toxins via the food chain.
Might this be related to climate change?
Research has shown that climate change is likely to cause an increase in frequency of algal blooms.
Should we be worried?
Any sudden death of seabirds like this should be a cause of concern, particularly given that, in Scotland, according to the Scottish Seabird Indicator, which tracks 11 seabird species, there has been a decline of 49 per cent since 1986.