Bird of the Week: Capercaillie

The handsome capercaillie is the largest grouse in the world, a similar size to a turkey. In the UK, these impressive birds are now only found in native pine forests and plantations in Scotland. They are believed to have become extinct from the whole of the UK in the 18^thcentury, probably because of a mixture of large swathes of the forests being felled, and hunting. Capercaillies were re-introduced in the 19^thcentury by sporting estates when more forest was planted.

Adult capercaillies eat plants; in winter this is mainly conifer needles and shoots and at other times of year it will be leaves and stems from plants like bilberries. In spring the females feed on nutrient-rich plant material, in particular cotton grass shoots and larch buds. The chicks will eat insects.

In the breeding season, the males perform a spectacular ‘lek’ when trying to attract a female and display in their own territory. Their instincts take over and become fixated with displaying, understandably so as the most impressive makes will get the majority of the females. 

One infamous male at RSPB Abernethy repeatedly attacked anything moving within his territory – even Sir David Attenborough when he was there to film his TV Series The Life of Birds. The amorous male, known as ‘Mad George,’ went for Sir David so energetically, he knocked him over! This level of lekking isn’t the norm, and only affects male capercaillie with unusually high levels of testosterone

Because capercaillie don’t form lasting pair bonds, it is hard to quote numbers in pairs, which usually happens with birds but there are thought to be 1,300 individual birds in Scotland.