After another fantastic visit to Langholm Moor on Wednesday, I came away with a surprising feeling of gloom. I was sent to gather information for the Heather Trust on treatments for heather beetle on the south end of the moor, and spent a great afternoon with Simon Lester (the head keeper) under chattering harriers and squeaking merlins. I’ve posted on this blog before about the damage caused by beetle at Langholm during 2009 and 2010 and the subsequent treatments which have since brought the lower ground back up to speed.
In truth, the habitat recovery is extremely impressive. It is just three weeks since I was last at Langholm looking at the same areas of treated ground, and the difference now is astonishing. Banks of flowering tormentil, sundew, heath bedstraw, rosemary and emerging asphodel have added a kaleidoscope of colour to the moor, undershot almost everywhere with the glow of tiny cranberry flowers like a pink galaxy of stars across the moss. Lush young heather plants crowded together in clumps, and at about thigh-height, oceans of cottongrass fruits bobbed and writhed in the breeze. The most notable absence from the moor was the sheer weight of grouse that this mixture should be supporting.
With the return of gamekeepers, the number of grouse at Langholm started to rise after the mess which was left in the wake of the Joint Raptor Study. Within a few years, the grouse stock was well up and looking set to support driven shooting. The keepers even started to fix up the butts in anticipation of the first days, but during the last few years that rising figure has reached a plateau at almost precisely half the amount required to sustain driven shooting. Despite a huge amount of work, the grouse numbers simply will not rise any further. Scientists have noted that the Langholm hens lay more eggs than the national average and the hatch rates are usually very good (95% hatch this year), but the chicks simply aren’t there in any quantity to breed for themselves the following year.
With the exception of last year, when the weather was so poor that empirical consistency with other years seems like a far stretch, the simple fact is that grouse are churning out eggs and chicks at Langholm. Productivity is huge and the habitat is some of the best I have ever seen. However, the evidence seem to suggest that the birds are simply not living long enough to continue building up their numbers. From my humble, anecdotal and scientifically useless perspective, I would suggest that the answer has something to do with predation.
It’s possible that Langholm was a bad choice of location for a moorland demonstration project. Since the Joint Raptor Study, the moor has been burdened with so much political baggage that it can probably never function as a place of objective science again. Having shown that it is possible to feed breeding hen harriers with day-old chicks so that they do not take grouse, the situation at Langholm no longer has much to do with hen harriers and shooting. Harrier predation is a negligible cause for concern during the breeding season, so we must look elsewhere for the birds which seem to be responsible for killing the grouse – I don’t think that it’s too difficult to imagine that buzzards and ravens have a part to play. These increasingly common predators have nothing to do with hen harriers, and the need to study the impact that they are having on the countryside grows with their expanding range and population.
Disturbingly, some people involved at Langholm Moor seem to be totally incapable of admitting that buzzards and ravens play even the most minor and fractional part in the difficulties of growing the stock of grouse. They look instead to obscure theories about habitat fragmentation in order to explain the grouse’s failure to grow, despite the fact that (even with its recovering beetle damage) Langholm is in much better condition than many moors in the Highlands which shoot driven grouse every year. This deliberate myopia is not science but politics – a cynic might interpret it as a deliberate refusal to consider the possibility that birds of prey might be having an effect. A “demonstration project” is the perfect place to run a trial study on raptor predation, but aside from a little tinkering, no such in-depth project seems forthcoming. I’m afraid that even if it did, the old “Langholm Moor is not representative of the U.K. uplands” chestnut would be ressurected to nullify the value of the results anyway. As a result, all the upbeat, positive moorland regeneration work which has been put in since the beetle outbreaks now risks slipping into a stalemate which is apparently beyond resolution.