Scotland remains a stronghold for black grouse
Numbers of black grouse on RSPB reserves in England and Wales are increasing, but declined in its northern strongholds in 2008.
Scotland is still where the bird is found in its greatest numbers, according to the conservation charity.
But it added that extremely wet early summer months in 2007 had hit chick survival rates north of the border.
Geltsdale Nature Reserve in the Pennines and Lake Vyrnwy Reserve in Wales have seen slight increases.
At Geltsdale the number of lekking cocks - birds which perform a morning courtship display to attract females - increased from 17 to 22, while at Lake Vyrnwy the number rose from 18 to 20 cocks.
However, the RSPB's Corrimony site in the Highlands has seen the number of lekking males drop from 57 to 53.
Abernethy Nature Reserve in the Cairngorms - the largest remaining expanse of ancient Caledonian pine forest in the country - saw numbers fall more sharply.
From a peak of 90 in 2007, they are down to 73 lekking males.
A smaller lek at RSPB's Inversnaid Reserve on the north east shore of Loch Lomond remains relatively stable, increasing from three to four displaying cocks.
The charity said this corresponded with population increases on neighbouring ground following habitat management work on land owned by Forestry Commission Scotland.