Black grouse adult male on lek at Corrimony RSPB reserve

Breeding

The black grouse is one of only three British bird species that exhibit lekking behaviour.

Lekking

This interesting phenomenon involves blackcocks displaying on a traditional lekking site. Most leks in Britain hold only 5-10 birds nowadays, but some large leks of over 30 birds are known. 

The cocks compete with each other for best display sites within the lek, with dominant individuals occupying central sites. The bubbling calls and the posturing of the cocks attract hens, who choose their mate. The dominant males in the central part of the lek obtain most of the copulations.

Black grouse Tetrao tetrix, adult male on lek. Corrimony RSPB reserve. Scotland.

Nesting habits

There is no pair bond between the two sexes, and males have no part in the nesting process or rearing of young.

The nest, a shallow scrape lined with grasses and moss, is made on the ground in the shelter of tall vegetation or low scrub. The 6-11 pale ochre or buff eggs spotted with brown are laid at intervals of 36-48hrs in late April. The female incubates the eggs for 25-27 days starting with the last egg. The young hatch together and leave the nest as soon as they are dry.

Black grouse Tetrao tetrix, adult male on lek. Corrimony RSPB reserve. Scotland.

Black grouse young

The female feeds the young on their first day, but from the second day onwards they are capable of feeding themselves. The young are capable of flight already at 10-14 days old. The female broods them for the first 10 days, and they are independent at about three months.

Broods remain together well into the autumn, and several families often join together to form small flocks.

Only one brood is raised in a year. Replacement clutches are laid if eggs are lost. Both sexes mature at one year of age, but males only mate at two years or older.

Black Grouse