Monitoring

Monitoring is crucial to the effort to save the black grouse. Only by having good information about where the birds are can we know where to target management, and success can only be measured if we know how many birds there are, and whether numbers are increasing or falling.

Because black grouse is a widespread species, surveys of the whole of Britain are expensive. The first was carried out in 1995-96, organised jointly by the RSPB, Game Conservancy Trust and government conservation agencies. The next UK wide survey is planned for 2005.

Recovery Projects in England and Wales have undertaken more frequent counts. In Perthshire, black grouse enthusiasts have formed a Black Grouse Study Group, which has been monitoring the population over 700 square kilometres annually since 1990. Similar groups have been set up in central Scotland and Strathspey.

The number of lekking male black grouse is the usual way of measuring the population, as the leks are relatively easy to find and view (compared to the nests). The standard method for monitoring black grouse leks was set out in Bird Monitoring Methods, published by the RSPB (Gilbert et al. 1998), based on those written for the 1995-96 survey by Brian Etheridge and David Baines, and reproduced below.

Breeding success is measured by counting broods in late summer, using pointer dogs to flush the birds in a controlled manner. However, this should be left to the experts, and is not something to undertake without training and experience.

LEK MONITORING
The information required from any monitoring is:
Maximum number of males attending the lek
A map showing the location of each lek

What to look for:
The number of males attending leks (communal display areas) varies between sites from only one or two birds, to more than 30. Although male black grouse are present throughout the year at lek sites, peak numbers occur during the breeding season in early mornings in spring.

Lek arenas are typified by having short vegetation and good all-round visibility: in-bye pastures on moorland and woodland edges, foddering sites on short heather, patches of young heather resulting from muirburn, and tracks and clearings in young plantations are all frequently used.

Several females may nest in the vicinity of a lek and each female may lay a clutch of 6-11 eggs from late April to early June. There is usually one brood. The young can fly at two weeks old but are not fully independent for 2-3 months.

Number and timing of visits
One visit (after several preparatory visits), between the last week in March and mid-May.

Time of day
Preparatory visit(s) to locate suitable habitat can be at any time of day. Preparatory visit(s) to locate leks should be up to two hours after dawn (preferably) or in the evening, before dusk. The visit to count males at the lek should be between one hour before and one hour after sunrise.

Weather constraints
Visit(s) to locate suitable habitat can be made in almost any weather. Visits to locate leks and count males must be in good visibility, in dry and calm conditions (wind not exceeding Beaufort force 3).

Sites/areas to visit
The preferred habitats for black grouse include mosaics of moorland or heathland, woodland, plantations, rough grazing, in-bye land and meadows. They are transitional or marginal between the enclosed fields on valley slopes and the lower edges of heather moorland. These habitats correspond to a distinct altitudinal range of 200-550 m. Previous work in Perthshire (Robinson et al. 1993) suggests that more than 95% of leks are located within this range.

Moorland
Within northern Britain, heather moorland, often managed for red grouse, is the main habitat for black grouse. They tend to be found on the edges of moorland from which they have access to other habitats such as scrub or woods, rough grazing and herb-rich in-bye pastures.

Native woodland
Black grouse favour two types of native woodland in the uplands: birch and birch/scots pine mixes. They prefer either small woods, woodland edges or even rows of shelterbelt trees. Open canopied woods are preferred as these allow sufficient light to reach the forest floor and create a field rich in herbs and dwarf scrubs. They avoid closed-canopy woods.

Forestry
The recent spread of afforestation in the uplands has resulted in short-term benefits for black grouse. Under relaxation from grazing and heather burning in the early stages of afforestation, heather, bilberry and scrub will form a luxuriant layer that can provide increased food and nesting cover. Black grouse numbers can thus be high in young forestry. However, the benefits are short-lived, and conditions rapidly deteriorate on canopy closure 10-15 years after planting.

Unsuitable areas
The following areas are generally unsuitable for black grouse leks and may not be occupied: ground above 550 m (600 m in England); ground below 200 m in northern England and southern Scotland (however, ground below 200 m can be occupied regularly if near to the coast, particularly in western and north-west Scotland); built-up areas; enclosed arable farmland; the interiors of unbroken post-thicket stage forest blocks and dense native woodland.

Equipment
1:25,000 OS map of the area
photocopied A4 field maps
prepared recording forms
telescope (if possible).

Safety reminders
Ensure someone knows where you are going and when you expect to return. Carry a compass and know how to use it. In more remote upland areas, carry extra clothing, food, a survival bag and first-aid kit. Always obtain prior permission from owners, tenants or their agents for entry to private land.

Disturbance
Do not disturb black grouse, particularly at a lek. Observe from a discreet distance. A lek can often be counted from a distance of several hundred metres (even from inside a vehicle) using a telescope.

Methods
Make sure the boundary of the survey area is marked clearly on a map. Make one or more initial visits to locate suitable habitat. Plan a route that takes you to within at least 500 m of every point. During these visits, mark on the map the areas of suitable and unsuitable habitat. Ask local people (gamekeepers, agents, etc) for knowledge of potential lek sites.

Make one or more further visits to locate leks, following a planned route. Confirm the locations of leks you have been told about and note the positions of any others you find. The number of visits required to do this will depend on the size of the area and the number of leks. Consider the best way to approach each lek to avoid disturbing birds. Under relatively calm conditions on bright mornings, the distinctive sound made by lekking males can be heard over a distance of almost 1 km. Early morning listening from a good vantage point overlooking suitable habitat can help to locate leks. However, the audibility of leks varies immensely, so do not use this as a substitute for visually searching all potential ground. If you hear a lek in the distance, always confirm its exact location. Depending on the terrain, one person should be able to cover a 5-km grid square in two or three mornings.

Carry out a dawn lek count within three days of a lek being located. To avoid disturbing birds as they arrive, be in position at least an hour before sunrise, when it is still quite dark. If during initial visits to the site, you are able to find a good vantage point from where you will not disturb any birds, you can be more flexible about your arrival time, as long as the count takes place within the count period.

Black grouse arrive at the lek in the half-light of dawn. Count the maximum number of males present in the period between one hour before and one hour after dawn. Count all males, not just those displaying. Not all males will be visible on the display ground at the same time, other males may be perched quietly in nearby trees or hidden by vegetation. Also count the number of females. Enter the counts on a standard recording form.

Treat leks that are 200 m or more apart as separate leks. Count all displaying birds you encounter within the survey area; note that some males lek on their own, often at transient, non-traditional sites. If a displaying male is separated from any other leks by 200 m or more, record it as a lek of one male.