Published in support of the UK Biodiversity Action Plan for black grouse

Ecology

Displays

Black grouse do not form pair bonds; instead, they have a promiscuous mating system that gives rise to the bird's most appealing and flamboyant display - the lek. Groups of males indulge in this complex display throughout the year, except when the feathers are moulting in July and August. During the lek, males defend their territories in the surrounding habitat. The hens only attend in spring (early April to mid May), which coincides with peak activity at the lek as the cocks compete for the attention of the hens, secreted away in the tall grass at the edge of the site.

Two black grouse lekking
Males dislaying at a lek. Abernethy Forest RSPB Reserve. Chris Gomersall, (RSPB Images 9001998-00457-002)

The cocks display by crouching and circling the ground, spreading their tails wide, showing off the striking contrast of their glossy black plumage and the white under-tail coverts. They partially extend their wings and inflate their vivid red wattles (the 'comb' above each eye) while producing a very distinctive bubbling sound that, on a still morning, can be heard from a kilometre (over half a mile) away. To see a video clip and sound recording of the lek, go to the RSPB's A-Z of Birds website and click on Gallery.

Leks tend to be traditional to particular sites, with the cocks defending their patches - the more dominant cocks hold the central positions and will mate with the most females. Lek sites are usually no more than 0.5 ha (1.2 acres) in area, on relatively flat, open ground with short vegetation, grazed by sheep or deer. This can be on pasture, the moorland edge, peat bogs, or - in forests - open glades and forest tracks. As numbers decline, leks become smaller, often until there is only a single lekking male. Where populations of black grouse are healthy, up to 40 males may attend a lek, but in recent years, most leks in Britain have fewer than 10 males, and only a handful have more than 20.

For information about viewing black grouse and their leks go to Information for Birdwatchers.

More on black grouse ecology...
Food
Habitat
Nesting