By Gerald Light
One recent early September we’d gone for a walk on Grassington Moor and taken our sandwiches with us. Although it was sunny there was a strong breeze blowing so we wanted to sit somewhere sheltered and one of the old lead mining spoil heaps nicely served our purpose. While we were eating there was a rushing sound just behind us and something almost touched Jo’s shoulder before twisting away to one side. The merlin must have been intending to perch on the top of the spoil heap, and been very surprised to find our heads just below it!
Experiences like this are infrequent, as merlin numbers on the moor are low and for much of the breeding season their behaviour is elusive. Juveniles in late summer or early autumn, sometimes still with a parent, often offer the
best chance. Without systematic surveying such as Peter Wright from Skipton carried out on Barden Moor and Fell from 1983 to 2002 (with extensions onto Grassington and Threshfield Moors from 1988) the local population is hard to gauge. Probably two pairs attempt to breed on Grassington Moor most years, but only occasionally one on Threshfield Moor. Here the greater density of paths can make noticing them easier, and a pair was seen to fledge at least
one chick in 2014. Either moor burning in that area that winter or the cold spring of 2015 apparently prevented a repeat the next season. Moor burning is good for red grouse as it maintains a mix of younger heather for eating and denser older heather for shelter and nesting. For birds like merlins however which like large areas of undisturbed older heather for breeding, burning patches or strips to any significant extent can be detrimental. Large scale burning is also increasingly recognised as having environmental disadvantages through CO2 release into the atmosphere and by increasing flooding risks down valley by promoting faster rainfall run-off, which also raises
the costs of treating water downstream to remove the peat.
Another aspect of moorland management, predator control, can also be taken to excess through the illegal persecution of avian raptors, and there are known “sink areas” for kites, peregrines and hen harriers not far outside the Upper Wharfedale boundary. Even within it two peregrines have been found shot in recent years: one on Grassington Moor some five Augusts ago was taken into care and recovered, one in Hebden Gill in October 2016 had suffered a fatal head wound. The legal control of foxes, stoats, weasels and crows is however generally helpful to wild birds. Fewer animals to steal eggs or chicks helps the breeding productivity of golden plover and moorland edge curlews and lapwings as well as the grouse.
Any such help is useful to most wader species, whose local numbers on the moors are at best static (e.g. curlew) or generally declining (e.g. lapwing, golden plover and dunlin). Only oystercatchers are now expanding uphill in some places from the valley floors and can increasingly be seen on the moorland edge. Nationally the breeding population of both curlew and lapwing has declined significantly over the last fifty years, with curlews retreating from most of SW England, Ireland and Wales. The British Trust for Ornithology (BTO) recently estimated that over 40% of English inland breeding curlew, lapwing and snipe are now found on the in-bye fields along the moorland edges of Northern England, emphasising the value of those we see in our area. The decline in lapwing is easy to appreciate in some places locally, for example while driving up from Halton Gill to the Wharfedale watershed between Pen-y-Ghent and Fountains Fell, but is not always so obvious elsewhere. Breeding numbers do in any case vary naturally from year to year, and a repeat survey of a two kilometre square between Skirethorns and Bordley last year found over twice as many lapwing as in 2008. Sadly there were also several sightings of stoats and the number of fledged young was low.
Golden plover have never been as plentiful in Upper Wharfedale as they are north of Wensleydale, where the extent of their preferred boggy moorland is much greater. Small numbers do breed annually on Grassington Moor and a restoration of predator control on Threshfield Moor in 2009 brought a couple of pairs back there. Breeding populations of both golden plover and lapwing generally leave our moors in July or August, resumably for lowland pastures or the coast in the first instance. In October and November however it is not unusual to find flocks of either on the limestone pastures fringing Grassington Moor or roosting on the shores of Grimwith Reservoir. Whether these are local birds returning to the area for a while after moulting, or migrant birds from further north, is unclear. One clue might be the regular presence in spring of migrant northern race golden plover at Dale Head on the Wharfedale/ Ribblesdale watershed, at a time when the greater extent of black feathering in their breeding plumage allows them to be distinguished from Pennine birds. Against this background of scarcity and decline it is good to report that our three regular breeding moorland songbirds – meadow pipit, skylark and wheatear – seem from survey results to be generally holding their own. While there can of course be perceptible year to year fluctuations, all three remain easy to see and hear on moorland walks. Pipits are fairly catholic in their choice of upland habitat, skylarks prefer grassy areas and wheatears need stones or walls from which to watch for their insect prey. In consequence the latter two are normally commoner in limestone areas.
Two other noteworthy moorland songbirds, ring ouzel (the “mountain blackbird”) and twite (the “mountain linnet”) are scarce summer visitors here. The former prefer dampish gritstone valleys, and as the national opulation declines (probably due to habitat changes on their wintering grounds in the Atlas Mountains of North Africa) they are retreating from the more marginal breeding grounds on limestone scars which they did occupy twenty to thirty years ago. Birds do still appear on migration in Hebden Gill, and may breed in some years, but the Buttertubs Pass and Swaledale further north are much more reliable places to see them. Twite are birds of the moorland edge, needing heather to nest in and a mix of rough grassland and meadow to feed in, very much a declining habitat in recent years. The last proven local breeding was in 2011, again on the Pen-y-Ghent/Fountains Fell col.
Seeing either of these two species while out walking is a definite treat and, for those who look, late summer and autumn can also bring noteworthy birds of passage. Young marsh harriers for example are fairly regular in August
over Grassington Moor, a black redstart was seen there with late migrant wheatears in early October 2015 and a snow bunting in November 2009. Best of all perhaps was late September/early October 2010, when an unusual
influx of Lapland buntings from the Greenland breeding population appeared in NW Scotland and spread out south-eastwards across much of Britain. One of these apparently spent ten days near the spoil heaps NE of the chimney,
being seen three times in that period, and was a splendid sighting for this area. Winter apart, when red grouse can be the only species to be found, there are more birds on the moorland round here than most people realise.