Monday, 1 December 2014

Pine Martens and Capercaillie

Image - Laurie Campbell
by Andrew Gilruth - @AndrewGilruth

If you walk through a Scottish pine forest and are lucky enough to hear and then see a ‘Horse of the Woods’ you will be amazed. That’s because the sound, like clopping hooves, will likely be coming from a one meter tall bird, a cock capercaillie, trying to attract a mate. Unfortunately this experience is becoming less and less likely. There are just 1,300 male capercaillie left in the UK (a 42% decline in 17 years) and the capercaillie is declining around the world.

Great effort has gone into improving Scottish forest habitat, but the decline still continues - sometimes more, sometimes less rapidly. The long-term decline seems to be caused by poor breeding success; cold, damp weather and high numbers of predators leading to the poorest breeding success. And studies at Abernethy Forest have shown pine martens to be a significant nest predator.

How important are pine martens in causing these declines?
No one knows; but we need to if our conservation efforts are to be best focussed. So there is a proposal to find out. The pine marten population is growing in Scotland and the idea is to study the pine marten population in four forests for six years. In two of the woods martens would be removed for each of three years, perhaps equating to 10 pine martens each year, to see if this will increase capercaillie breeding success. Then the treatment would be reversed and martens would be removed from the other two forests.

Is this a cull?
No. There is no plan to lethally control the pine martin population across Scotland. If the research indicates increasing pine martens are a factor in capercaillie declines, efforts may be focussed only on a small area in Strathspey, helping protect 75% of our remaining capercaillie.

Is this level of intervention new?
No. Predator control for conservation is already undertaken.

Is it true the capercaillie has been extinct before?
Yes. The capercaillie became extinct in the 18th century following extensive felling of pinewood habitats and a run of cold, wet summers in the 'Little Ice Age'. It was re-introduced into Scotland, by landowners with an interest in shooting, in the mid-19th century. By the 1970’s there were 20,000 capercaillie in Scotland.

Are capercaillie still shot?
No. There was a voluntary moratorium on shooting from the late 1980s and full legal protection came in 2001 - but the decline of the capercaillie still continues.

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  1. Are the 'removed' pine marten to be relocated or killed? Pine martens in the south would help address the grey squirrel numbers.

  2. Does it really need a study to determine if capercaillie breeding success will increase in the short term if pine martens are removed? The answer will probably be yes in the same way that waders and other ground nesting birds on grouse moors will do better because of legal (and illegal) control of predators. But this ignores the other factors that cause the decline of the capercaillie and other birds to a point where they become increasingly vulnerable to the effects of predation.

    The shooting community and conservationists have different objectives - the former wants to encourage the numbers of target species to a point where it is viable to run a shoot - these are usually at unnaturally high numbers and require predator control to achieve that. The latter aim for creating and protecting habitat that provides as natural a bio-diversity as is possible in our crowded island and that is generally in balance with the least possible predator control, if any, simply because those predators are part of our wildlife heritage. Many supporters of shooting claim that predator control (removal) is essential to maintain bio-diversity and that predator numbers are out of control. The truth is that this is not proven and the primary driver for predator control is to maintain unnaturally high numbers of game birds for shooting. This study will add nothing to what we already know. It is all too easy to paint predators as the villains but let us be clear that their culpability is much less certain once one understands the objectives of those that do the painting. The irony of course is that creating unnaturally high numbers of game birds for shooting (particularly the millions of pheasants bred and released every year) and the restricted range of some of our more specialist apex predators (such as goshawks and golden eagles) due to persecution, probably bolsters the numbers of those generalist predators that can be legally controlled. If you want to control crows encourage goshawks to breed on your patch! Now this would be an interesting study of some value to all.