How robocutters can improve capercaillie habitat

Improving and creating more habitat for capercaillie is one of the Cairngorms Capercaillie Project’s five essential actions, so we are excited to be working with RSPB Abernethy Nature Reserve. Together we’ve been making use of clever machinery – namely the robocutter – to improve conditions for plants on the forest floor (the ‘field layer’). So why is this important for capercaillie?

In areas where heather has become thick and overgrown, capercaillie chicks in particular find it difficult to move through and dry off in the increasingly wet spring weather. This leaves the chicks at risk of hypothermia. Tall heather also makes it hard for field layer plants like blaeberry and other vegetation to grow. Cutting back tall heather will encourage the growth of such plants and attract insects, both of which are important parts of the capercaillie’s diet throughout their lifecycle.

A robocutter controlled by its operator

How does a robocutter work?

A robocutter is essentially a small remote-controlled tractor, its movement directed by an onsite operator. It makes very quick work of cutting even the toughest of heather (it’s designed to cut through gorse!); rolls happily over a variety of terrains; and can reach an angle of 55 degrees before it would tip over.

We were lucky to be given a demo of a robocutter at RSPB Abernethy last October.

The machine fits into tight spots and its cutting plates can be lowered and raised as needed, making it altogether more flexible than a standard tractor. This makes it much easier to work around the things we want to preserve for biodiversity, such as native saplings, healthy blaeberry and wood ant nests.

A lucky find: A Scots pine sapling right beside a wood ant nest, both expertly avoided by the robocutter!

Nothing is wasted either – all the cut vegetation is pulverised into a mulch and left on the ground, forming a good base for tree seeds to bed in and grow.

After 3 years the impact of the robocutting will be monitored. Measures of success will include field layer growth and health, insect levels, general biodiversity, and importantly capercaillie productivity. 

There are already promising results from the past few years, as robocutting isn’t a new operation in Abernethy: It began in 2019 and in the time since, there has been evidence of capercaillie presence in the cut areas (such as droppings and dust baths). Narrow headed wood ants had also been colonising in recently-cut parts, as well as Scots pine, rowan seedlings and fungi.

It was fascinating to see RSPB Abernethy Nature Reserve’s cleared trial areas from the year before, where new blaeberry plants were already surfacing. These may feed a capercaillie next spring!

How is disturbance in the forest mitigated?

To reduce disturbance, areas are only cut every 8 to 10 years, taking place in the winter months to avoid the breeding season. Being much smaller than a standard tractor, the robocutter also minimises the creation of tracks in the forest, which could be used by predators or humans. Covering about a hectare a day, the work is localised and – much like forest thinning – wildlife becomes used to the routine of the activity.

Looking to the future

Will it be cows or robots? In Abernethy, RSPB’s Life 100% For Nature project has been trialling robocutting alongside natural grazing by cattle, both with interesting and promising results. The cattle grazing mimics the movements of aurochs (ancient cattle) in millennia past. RSPB staff are even spotting evidence of capercaillie taking dust baths in areas of cattle-trodden ground. You can find out more in their blog

It will be great to see how these trials progress and what it means for the future of forest management, particularly in capercaillie areas – and it’s exciting to be a part of these operations and to see their impact unfold.

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