The Seton Dipper

Having scoured the Seton tetrad for 6 years now I was initially sceptical when receiving a report of a Dipper at Seton Chapel in early July, seen by persons unknown, however an LBN appeal led to Murray contacting me with concrete info on his sighting - below the bridge in grounds of the Chapel monument when he was looking for the parakeet; I then followed up and found plenty of evidence by way of droppings at the small burn through the Chapel grounds - but no sign of the bird itself! Worse, the stream was running pretty dry and even at the best of times much of it is underground, including the last 500m from the House to the Seton Burn bridge on the coast road, just perhaps 100m of proper flow on that side. Minimum territory size for Dipper in good habitat is 100m, so it looked a bit marginal to support even a single bird for any length of time. Bird-aware residents at Seton House and the Seton Mill House had not seen it either, though there were also a few droppings at later location.

Too busy with atlas to look further in July but then Willie came to the rescue again refinding it at the nearby Blindwells Minewater Treatment Scheme on the other side of the A198 on 6 August. There is even less open watercourse on this side, and the sludge beds are now full of reeds way over head height, but there is a weir-like full length drop between the lower two tanks and exposed flowing water there which may well suit it very well. Photos here from Thursday 8 August, was content to rest a few minutes while I watched it, gently bobbing - NB, it is a juvenile of the species so a recent dispersal!

Why the interest? As far as I'm aware there are no historical records of Dipper here, and the nearest occupied territories are 4-5 miles distant on the lower River Esk and upper River Tyne. There are no waterways in between - and though the initial thought might be a displaced bird moving along the coast from the Esk in winter this seems pretty unlikely as it would need to fly inland at a random location to find the water it has now colonised (not relevant anyway to a juvenile). I'd guess it has more likely dispersed from the Tyne and been drawn in by the larger area of wetland including the adjacent Blindwells pond.

Do Dippers do this? The Price & Bock account of their American Dipper (Cinclus mexicanus) studies* contains some relevant and interesting information (p. 32) with two records of overland flight observed, one historical record in 1922 of a 400m movement across a Y in a river and their own sighting in 1971 of a bird displaced by others flying off overland and climbing to a height of 60m. They also refer to other movements between watersheds from their ringing studies that they attribute to movements overland, other routes along waterways being unfeasibly long and away from typical habitat. More relevant to the current case are references there to the observations in Jost's (1969) paper** on our European Dipper (Cinclus cinclus) documenting movements between watersheds by juveniles in the German Rhoen, and additional finding that adult Dippers make regular migrations across the high Swiss Alps where the lowest passes are over 2000m - Dippers caught in mist nests above the tree line! However all of these studies relate to higher altitude steep terrain, whereas the current case would involve a climb and descent of no more than 50m in 4+ miles. UK vismig records on trektellen show this species has not yet been logged on migration here, the only records being birds appearing at a Redmires reservoir which is connected to a waterway, but how many are we missing? Since posting Stuart has alerted me to his observation of a Dipper on the Cart Water in centre of Paisley flying off high above tenements.

So it turns out it can't be added to atlas as a juvenile. Plenty of genuine breeding activity still underway, thick with young birds along Blindwells margins with young Sedge Warblers (scolding parent below) and Whitethroats, I still live in hope that Tufted ducklings may yet emerge at Blindwells, the female having vanished again and the two drakes resident all summer. Also two families of young Bullfinch seen this week, and plenty gamebirds - see previous blog post. The atlas lives on for now!

* Price, F.E. & Bock, C.E. (1983) "Population ecology of the Dipper (Cinclus mexicanus) in the Front Range of Colorado", Studies in Avian Biolody No. 7. (download link)
** Jost, O. 1969. Über die bedeutung der wassersheiden beim ortswechsel der Wasseramsel (Cinclus cinclus aquaticus). [On the significance of water sheds in the movements of the Dipper (Cinclus cinclus aquaticus).] J. Ornithol. 110:71-78 [English sum.] (download link)