In light of recent coverage in The Guardian and The Herald, we would like to take this opportunity to revisit a blog post we wrote in December 2014:
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.
Is predation a big factor in the decline of capercaillie?
We know that even in a year when the weather is good, about two thirds of capercaillie hens have no young at the end of the breeding season. Some of these losses are likely to be due to predation but we need to further explore the effects of predation separated from other factors. Previous studies have highlighted the importance of improving breeding success to restore capercaillie numbers.
Which predators?
More research is needed to tease apart the effects of individual predator species, particularly in the core of the capercaillie’s range. Analysis of the available data suggests more chicks were reared in years when the weather was better and where crow and pine marten numbers were lower, but our research also showed that adult capercaillie numbers were highest in forests with lower fox numbers. Crows are more important in explaining capercaillie breeding failure and foxes are implicated with lower adult survival. Surveys in forests undertaken in collaboration with SNH, FCS and RSPB showed that crow and raptor indices have remained similar over 14 years. However, fox numbers increased by just over two fold and pine marten by nearly four fold.
What should we do next?
In the long-term, habitat improvement and expansion is key to ensuring a robust capercaillie population in Scotland. However, in the shorter term, to improve breeding success and allow young birds to boost the population, we advocate the effective control of crows and foxes in and around forests. If increasing control of these two generalist predators does not increase productivity for capercaillie then we may need to consider a licensed experimental non-lethal pine marten removal study, which could form part of wider re-introduction programmes for the mammal.
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 1970s 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.