Important to note the discovery of what could well be a breeding pair of dippers on the Chayne. I disturbed two birds below the waterfall on the back hill, and while one motored briskly off downstream, the other flew in a strange spiral of loops up into the air, singing all the while. Despite having spent a good deal of time watching dippers, I have never seen this behaviour before. In many ways, the sound resembled the scratchy, rather awkward song-flight of a cock wheatear against a roaring backdrop of bubbling water. Before this comparison was fully formed in my mind, the bird had vanished briskly behind a nearby dyke with all the plummeting enthusiasm of a starling dropping in to roost.
This is superb news – In almost eight years, I have only ever seen a single dipper on the Chayne, and that was a bird in the depth of midwinter which had no interest in settling and simply flew back downhill as briskly as its stubby wings would carry it. Having been taught to assess invertebrate populations during a day’s course with the Galloway Fisheries Trust last year, I was very pleased to find that the burns on the Chayne are full of life – when I shuffled about conducting “kick samples” with a net, I found that they scored very highly on all the main invertebrate groups, particularly for caddis flies and olive mayflies. It would seem that there is more than enough food for dippers to support a few breeding pairs, but they are probably being scuppered by a lack of suitable nest sites and a shortage of decent riverside vegetation which would allow them to hide from predators.
The highest density of dippers I have ever encountered was on a network of remote highland burns in the Monaliadths near Fort Augustus, where it seemed that the little birds were lurking behind every rank tuft of heather. I know that they are capable of hiding underwater in moments of stress or upset, but surely it helps to have some dense cover nearby on terra firma, particularly for young birds when predators to visit.
A lack of suitable vegetation is the short-term bottleneck through which so many of my efforts are stymied, but I can do something practical about nest sites. A little research online suggests that dippers will use nest boxes, and now that I come to think of it, the huge majority of dipper nests I’ve seen have been in bridges, concrete walls, drainage pipes and other man-made locations. I am surely too late to provide nest sites for this year, but it’s certainly a subject that I will come back to.