Raptors have long been accused of ‘eating too many’ red grouse, and none more so than at Langholm.
Sure, we all know that some raptors can eat a lot of grouse – during the Langholm 1 study it was shown that raptor predation reduced the autumn grouse abundance by 50%, leading to the cessation of driven grouse shooting (here). In other words, the ‘surplus’ birds from an artificially-high red grouse population were no longer available to be shot and the red grouse population dropped back to normal (natural) density. But we also know, through the work completed during the recent Langholm 2 study, that diversionary feeding of hen harriers has shown that the proportion of red grouse in the diet of diversionary-fed hen harriers was a negligible 0-4% (see here).
Seeing as (diversionary-fed) hen harriers could no longer be blamed, attention switched to blaming the buzzards. Simon Lester, the now former Head Keeper at Langholm is quoted in a 2014 book A Sparrowhawk’s Lament as follows:
“I can put my hand on my heart and say that harriers aren’t a problem. Harriers aren’t limiting grouse at Langholm because diversionary feeding works. What’s stopping us shooting grouse is Buzzard predation“.
Unfortunately (for Simon), this claim of buzzard predation causing problems at Langholm is wholly unsupported by the scientific evidence. Research undertaken during three breeding seasons at Langholm 2 (2011-2013) showed the proportion of red grouse in the diet of buzzards was just 1-6% (see here and here).
‘Ah, but what about buzzard predation during the winter?’, cried the grouse shooting community. Well, that question has just been answered by the latest study, published last week. It turns out that not only aren’t Langholm buzzards taking many grouse during the breeding season, they’re also taking bugger all during the winter. Over a period of two years, red grouse formed 1.1% and 0.6% of prey items, and occurred in 3% and 2% of pellets from each winter, respectively. Small mammals were the main prey in both years, comprising 60–67% of items and occurring in 88–92% of pellets.
Despite such robust and compelling evidence, there are some who still want to pin the blame on the buzzards. Last November, Mark Oddy (Buccleuch Estates – one of the Langholm 2 project partners) suggested, “We now have to grasp the nettle and try and put forward a case, which probably in the first instance under licence, will allow some type of lethal control, ‘cos I don’t see what the future alternative is” (see here).
And in July this year, Tim (Kim) Baynes of Scottish Land & Estates wrote: “The confounding factor seems to have been the overall impact of buzzards, ravens and other raptor species predating adult grouse all year round, with harriers starting to overwinter on the moor, too“. He went on: “There were 80 pairs of raptors from seven species nesting on and around the moor at the last count, excluding ravens. Everyone involved now agrees that this level of multi-species raptor predation makes grouse-shooting unviable. Demonstrating this is a vital step in making the case for action to resolve it“.
Eh? Can these people not understand simple scientific data? Or are they just choosing to ignore the evidence?
Give it up guys, Langholm buzzard dietary studies have been done to death: they’re not really in to eating red grouse.