Scotland's under-threat capercaillie population boosted by "diversionary feeding"
Aberdeen University-led study in Cairngorms sees numbers rise
A study focused on protecting Scotland’s capercaillie population by managing predators through non-lethal means has seen brood numbers double in target areas.
The capercaillie is a ground-nesting bird that, with just over 500 left in the wild, is in danger of extinction in the UK. One contributor to its decline is the eating of eggs and chicks by predators, including another protected species, the pine marten.
Diversionary feeding is a conservation technique designed to reduce predator impacts on vulnerable species without harming the predators themselves. By providing an alternative, easy meal - deer carrion in this study - it gives predators a readily accessible food source so they don’t need to search for rarer food like capercaillie nests in the same area.
Three-year study in Cairngorms
Conducted over three years in the Cairngorms, the research is the result of a partnership between the University of Aberdeen, the University of St Andrews, Forestry and Land Scotland (FLS), RSPB Scotland, NatureScot and Wildland Ltd working under the umbrella of the Cairngorms Connect Predator Project.
It used camera traps to monitor capercaillie broods in locations where diversionary feeding was in place. Researchers found that in areas where alternative food was available, 85% of capercaillie hens detected had chicks, compared to just 37% in unfed sites.
This resulted in an increase in the number of predicted chicks per hen, more than doubling, rising from 0.82 chicks per hen without feeding to 1.90 with feeding – an increase in capercaillie productivity by 130%.
The study confirmed that the boost in chicks per hen was directly linked to a higher chance that a hen had a brood at all, indicating that diversionary feeding reduces catastrophic brood failure often caused, by nest predation.
It follows the success of artificial-nest research
These findings build on earlier results from an artificial-nest study published in 2024 that found a nearly 83% increase in artificial nest survival from a 50% reduction in pine marten predation, with diversionary feeding.
The latest research shows the results translate to real-life breeding outcomes.
“This study provides compelling, robust, landscape-scale evidence that diversionary feeding can reduce the impact of recovering predators, without killing them, aligning with shifting ethical and ecological goals for conservation management in the UK,” said Dr Jack Bamber, lecturer in Ecology and Conservation at the University of Aberdeen’s School of Biological Sciences, who led the research project.
“The combination of rigorous experimentation and innovative monitoring indicates that this method is worth exploration for other species vulnerable to predation, with land managers concerned with other rare prey, and land managers aiming to help capercaillie elsewhere in Europe already considering this tool as an option for them to trial and apply in future.”