As the season has progressed, the weather has well and truly broken down and with it the size of attainable bags keeps dropping, too. Unless we get some respite, several moors will end the season with far too many birds left on the ground for the good of their health. It will not be because the keepers have not tried to shoot them, it will simply be because nature has decided otherwise. A hurricane from the US hit the UK, and it disrupted yet another week?s shooting for many moors, with days cancelled, or at best, bags reduced severely.

A mug?s game

There are some keepers and owners who, for a few years now, have been trying to build up grouse stocks to unsustainable levels in an effort to get that really big season and make their mark in the history books of grouse shooting. Despite the new generation of medicated grit, along with many other keepers, I feel that having too many birds on the ground will simply lead to something else bringing the stock back down. It may be coccidiosis, but it could well be something completely new afflicting our grouse. Whatever it is, it will come, and this has always been the case with overpopulation of any species.

A new generation of diseases

One gentleman told me his father had given him some advice when he started farming: ?Don?t worry about keeping too much stock, it will soon die back to the correct level.? That is as true when dealing with gamebirds as it is with farm livestock. It is not a good way to keep stock of any description though, far better to keep the correct number in good condition than too many in a poor one.

For many years, the bible of grouse management, The Grouse in Health and Disease, spent considerable time discussing the merits of cocci, as it is commonly known, regarding large-scale losses in grouse populations. Cocci has been recognised as a killer of gamebirds for many generations. But what of the new generation of diseases?

Mycoplasma is one, which has now been confirmed in red grouse, but is it new, or is it simply that we have not been looking for it? I gather that it has been in the background of gamebird diseases for many years, mainly coming to the fore when pheasants and partridges are put under stress. There are others such as the variations of avian flu, which could prove devastating if they ever got going in a population of red grouse.

Treatments rendered ineffective

Part of the problem grouse keepers face compared with lowground keepers is that there is a difficulty finding any way of treating stock. It has taken nearly a generation to refine medicated grit to treat strongyle worm ? the other diseases we now face are far more problematic.

We cannot, for example, put any treatment into water supplies, as at certain times we are washed out with the stuff, and many drugs are affected by exposure to light, so any hope of fixing them to grit is a non-starter. Interestingly, the confirmed cases of mycoplasma have not occurred in high-density grouse populations, so what is it that has triggered this debilitating disease to rear its head on the grouse moors?

True, there have been some serious outbreaks of heather beetle, the results of which can cause serious loss of the birds? food supply, but that plague has hit on previous occasions and there would seem to have been no sign of mycoplasma until recently. It may well be that it has jumped the species barrier from pheasants and partridges.

For several years, this has been a real worry for many moorland keepers whose moorland lies alongside high-density pheasant and partridge shoots. The problem with the theory of disease jumping from one species to another is that the confirmed cases do fit that bill. The real problem with mycoplasma is that it is passed on from one generation to the next via the egg. Once it is present in a moorland population, is it always going to be there, and can it lie dormant for many years only to return to bite you every now and again? So many questions, but so few answers.

It may well be that keepers who read this article might look a little more closely at the odd casualty they find on the moor, and if fresh enough, send them off to a laboratory for a post-mortem. Only by looking at a good-sized sample will we find out just what diseases we have in our grouse and what the long-term consequences may be.