Our guest blogger today is Sarah West.  Sarah is the Capercaillie Project Assistant,  joint-funded by RSPB, Scottish Natural Heritage and Forestry Commission Scotland.  Here she gives us a brief insight to the fifth national survey of this elusive bird; an RSPB and SNH project.

Capercaillie (Tetrao urogallus) male displaying in snow-laden forest, Scotland ©Pete Cairns/2020VISION

The capercaillie is a large but rarely seen grouse that makes its home in the pine forests of the Scottish highlands. They are generally shy and avoid contact with humans, disappearing into the trees before you realise that they are there.

However, capercaillie are quite famous for their springtime get-togethers where males dance to attract hens to mate with. This communal dance is known as ‘lekking’, and every year we monitor the number of birds attending these leks. However, this does not provide us with an accurate population estimate as many birds won’t attend the lek sites, or will only visit sporadically. Therefore, the national survey was devised to count birds seen in a representative portion of capercaillie habitat across Scotland which could then be extrapolated to provide an idea of the population size of these beautiful birds, and to see how this changes over time.

Capercaillie (Tetrao urogallus) male displaying, Scotland ©Pete Cairns/2020VISION

The first national survey was carried out in the winters of 1992-1994 and produced an estimate of 2200 birds, a decline of 90% since the 1970’s and a serious cause for concern. The second national survey took place in the winter of 1998/99 and showed a further decline to just 1073 birds, proving that, without help, capercaillie would once again face UK extinction.

After this poor result, more effort was put into research and forest management to benefit capercaillie; areas of suitable forest habitat were expanded and joined together, deer fences have been removed or marked to avoid collisions, and predators are controlled to increase chick survival. The national survey is repeated every six years and this positive management for capercaillie has been reflected in its results, with the 2003/04 survey turning up 1980 birds, and the most recent survey in 2009/10 revealing 1285 birds. The extreme winter weather and long-lying snow in 2009/10 meant that many areas were inaccessible.

Capercaillie tracks

This year marks the fifth national capercaillie survey, taking place over the winter of 2015/16. Six people were recruited to complete this survey, which covers all capercaillie areas in Scotland; from Easter Ross to the Trossachs. The survey itself is made up of over 700 triangular ‘transects’ (2 km long routes to walk whilst counting capercaillie). These transects are randomly distributed across capercaillie areas, with many in remote forests or crossing difficult terrain, often involving long walks into each survey area.

The national survey runs over winter in part to avoid the breeding season when capercaillie are most sensitive to disturbance, but this can make things tricky for the surveyors. Rain, snow and high winds all conspire to make this a difficult survey, especially considering the short day-length and more than 700 transects to complete. Add to that forest bogs, windthrown trees, deer fences and rocky terrain and you’ve got one tough survey!

In addition, capercaillie sightings are not guaranteed as they are a scarce species and, despite their large size, they are shy and well camouflaged so are often difficult to spot as they remain hidden in trees as you approach, staying perfectly still and hoping that you don’t see them. Usually the only sighting that you’ll get is the tail end of a bird as it bursts from a tree in an explosion of noise and frantic wingbeats, out of sight in a few seconds. But every encounter with a bird is important for the survey so that we can get an accurate estimate of capercaillie numbers in Scotland.

Sarah West

The national survey fieldwork runs until the end of March 2016, followed by some serious number-crunching so we won’t know the new population estimate until the following year but we are hoping for a good result – an increase in birds.

Photo credits.  Images 1 and 2 ©Peter Cairns/2020VISION , Images 3 and 4 © Sarah West.