Black Grouse (Tetrao tetrix)

Filling in the niche between the tundra grouse (Willow Grouse, Ptarmigan) and the forest grouse (Capercaillie, Hazel Grouse), the Black Grouse is a bird of transition habitats between closed forest and open ground. A widespread species in northern Europe, it may be found on heaths, moors, bogs and forest clearings, so long as there are groups of trees nearby. Broadly speaking it feeds on the ground in the summer months, and up in the trees in winter, making use of its whole habitat.

By Steve Garvie from Dunfermline, Fife, Scotland – Black Grouse (Tetrao tetrix) Male, CC BY-SA 2.0, https://commons.wikimedia.org/w/index.php?curid=11461073

You would be hard pressed to know that male and female Black Grouse were the same species just by looking at them; they are behaviourally and morphologically very distinct. They don’t associate much, either. In winter the Black Grouse is a sociable bird (gatherings of up to 1000 have been recorded), but most males and females flock with their own gender. The males, indeed, have a shared home range, and spend much time in each other’s company.

Not all of their time is spent amicably. In fact, on many a morning both in autumn and spring, the males congregate at traditional areas known as arenas to display and fight each other. Usually selecting an open site such as a clearing, the males droop their wings and lift up their tails to reveal their bright white undertail coverts. They participate in mock or real fighting, and make a continuous dove-like cooing punctuated by sharp hissing sounds, like the release of volcanic gas.

By Billy Lindblom from Hallsberg, Sweden – Black Grouse (Tetrao tetrix), CC BY 2.0, https://commons.wikimedia.org/w/index.php?curid=19521127

On the arena the males’ small territories are bunched together in close proximity, so that the arena acts as a communal display ground, or “lek”. Each male has a territory somewhere on the lek, but the choice territories are in the centre, and this is what the fighting and posturing is about. Knowing that all males aspire for the central territory, and therefore reasoning that the best male actually resides there, each female ignores the attentions of marginal birds and goes straight for the best genetic material. Marginal males may not copulate at all during the season.

This red-blooded system of mate selection confines copulatory activity to a brief peak of about 10 days in the season. Each female may visit several leks and add variety to her brood of 6-11 eggs. She is then responsible for looking after eggs and young, whilst the males carry on as usual.

From ‘Birds: A Complete Guide to All British and European Species’, by Dominic Couzens. Published by Collins and reproduced with permission.