Black grouse (scientific name tetrao tetrix) have been spotted at RSPB Geltsdale, so this week we are profiling this distinctive, endangered bird, its habits, the threats it faces, and what you can do to help.
Male and female black grouse look very different – the all-black males have a bluish sheen to their feathers, a distinctive red wattle over their eyes and a striking white stripe along each wing in flight. The males are much larger than the females, weighing in at around 1.2kg, and have a lyre-shaped tail which is fanned out to show white feathers underneath when they are displaying (attracting a mate). Meanwhile, the females are smaller and grey-brown in colour, weighing an average of 930g, and have a slightly notched tail.
Black grouse numbers are limited, largely due to habitat loss and overgrazing, making them a Red List species, although positive habitat management is seeing numbers increase in some areas. They can be found here at Geltsdale and across the North Pennines, in parts of Scotland and some upland areas of Wales. They favour farmland or moorland with forests of scattered trees nearby.
Black grouse undertake an interesting mating ritual, called ‘lekking’, in which the males, known as ‘blackcocks’, display at traditional sites. Most lekking sites, or ‘leks’, in Britain only hold five to 10 birds, although some large leks of more than 30 birds do occur. Lekking usually occurs in spring and the cocks compete with each other for the best display sites within the lek, posturing and using their bubbling calls to attract hens, who then choose their mate. Lekking is essential for the black grouse’s breeding success, but can be hindered if they are disturbed. If the birds are disturbed during the key months of early April to early May, they may not mate at all. They are also vulnerable when nesting and rearing young.
A cock and his hen do not bond once mating is over and the males play no part in nesting or rearing chicks. The females make shallow nests, or ‘scrapes’ on the ground, sheltered by shrub or vegetation, and line it with grass and moss. Six to 11 eggs are then laid at intervals of 36 to 48 hours in late April, and the female incubates the eggs for between 25 and 27 days. The young then hatch together and leave the nest as soon as they are dry. Young black grouse are fed by their mother on the first day, but after that are capable of feeding themselves. They can fly at 10 to 14 days old and are independent at around three months. Broods stay together until well into autumn and several families may join together to form a flock.
Some key guidelines if you’re out birdwatching and looking for black grouse are:
The best way to see black grouse is to book onto a guided walk led by one of our wardens. We have one coming up on April 1st – to book tickets go to Black Grouse Walk (rspb.org.uk).