Gloomy predictions have again greeted the Glorious Twelfth

With the traditional "Glorious Twelfth" shooting, they have decided to save dwindling numbers, with climate change and disease key problems.

Some estate managers concluded that the grouse had not bred strongly enough to sustain a shooting programme.

The major problem is a tick on sheep which carries a virus that can wipe out up to 80% of chicks.

Although the grouse population has declined overall, in a few areas breeding has been good and shooting is going ahead.

Experts said that it seemed that this year the grouse population had been stronger in the higher moorland areas.

In general we are looking at the worst year in perhaps the last 10 years Colin Sheddon British Association for Shooting and Conservation

They predicted it was likely that Highland estates should see the best of the shooting.

The Game Conservancy Trust said at the start of last season that global warming had caused problems.

Insects which chicks depended on were appearing too early, while beetles attacked their other food, heather.

But the Moorland Association was more optimistic at the time.

Grouse shooting can normally expect to bring �15m to �20m into the Scottish economy in an average year.

Very poor

Colin Sheddon, Scottish director of the British Association for Shooting and Conservation, said that unseasonably cold and wet weather had played a major part in the poor grouse numbers.

He said: "In general we are looking at the worst year in perhaps the last 10 years, while in England they are saying it's the worst in 50.

"The breeding success of the grouse has been very poor in most areas and the general picture is that cold, wet weather at the end of May and beginning of June has had an adverse effect."

One estate in the Lammermuirs in the Scottish Borders reduced its number of shooting days from the usual 16 to just two after a count found the grouse figures "substantially down".

Simon Bostock, Chairman of the Moorland Association, said some grouse counters had reported seeing fewer than 10 birds in areas they would normally see more than 300.