Committee of Inquiry on Grouse Disease

“ No discussion is more apt to produce different opinions than that which arises upon the age or the sex of Grouse in certain stages of moulting, either at the luncheon-hour upon the moor or in the game-larder when the day's bag has been overhauled, and hung upon the hooks. It must be admitted that there are individual cases occurring not rarely, in which it is almost impossible to tell the sex until the bird has been cut open and the internal anatomy examined. ”

“ The young Grouse, even although they may be squatting within a few feet of the observer, are very difficult to find; they seem to have the power of making themselves invisible at will, as they cunningly crouch by the side of a tuft of grass or heather, which often matches in colour the yellow, brown, and chestnut mottled down that covers their little bodies for the first few weeks. ”

“ In spite of the confident statements of gamekeepers that they can tell by the size and plumage of a bird that he has come from a certain district many miles away, it is more than probable that the newcomer has always had his habitation within a few miles of the neighbouring march, or even that he has never left his home, but has disguised himself by a sudden moult. ”

“ If an April bird has newly and thickly feathered legs and feet, it means, almost certainly, that the "winter" plumage has been put on very late. The healthy Grouse should now be moulting the feathers of the feet and legs, so that bareness or lack of feathers becomes in them a sign of health in April, and thickly feathered legs a sign of sickness; this is the precise contrary of what has almost become proverbial on the moor, that bare legs indicate disease; though for the later autumn months the saying is quite true. ”

“ Even in the summer months when the cock puts on a plumage closely simulating the breeding plumage of the hen, there is a difference in the general tone and colour, and confusion is not likely. But in the autumn and winter it is comparatively easy to mistake the sex of some individuals, for when the hen has put on her autumn plumage for the winter, and the cock has put on his winter plumage, certain individuals of opposite sex are then indistinguishable, even to the practised eyes of the experienced gamekeeper. ”

“ On many moors the sheep drains have been scoured by floods into deep chasms, from which it would be difficult for the chick to emerge on the approach of danger, and any one who has seen a hill drain immediately after heavy rain, when it is running bank high in a miniature torrent, can picture the risk which might attend any attempt on the part of the mother bird to lead her brood over the obstacle. ”

“ While the circulation is active in the feather shaft, and for as long and in so far as it continues, pigmentation may be altered, but once the circulation has ceased beyond the entrance to the base of the shaft, and once that the feather, although still attached to the epidermis, is cut off from the circulation in the deeper living layer of the skin, then the feather is no more likely or able to change the pigment which is responsible for its pattern or its colour than would be the same feather had it been plucked out and kept entirely separate from the bird. ”

“ In most Red Grouse, even in the vast majority, the confusion of sex is not possible, for it is a matter of common knowledge that for a great part of the year the cock and the hen are so wholly unlike one another as to make it difficult for any one who did not know the birds to believe them to be of the same species. ”

“ Even in Yorkshire, Lancashire, and Derbyshire the ground does not appear to be better suited for the growth of heather than in Scotland, yet in these counties the stock of district birds is proportionately much greater. The difference is partly to be accounted for by the fact already noted, that the heather in the north of England is of a better quality, that is to say with many more stalks to the acre, than the rank growth of the west of Scotland, but it has also been suggested that in the former country the normal weather conditions are more favourable to the ripening of the heather seed. ”

“ Ground which has been covered by snow for a period of several months provides better and more wholesome food than ground which has been heavily stocked, for when birds return in the spring they find the food supply still untouched by Grouse or Sheep, and the fact that it has been out of reach for so long has prevented it from being so heavily infected by the larvæ of Trichostrongylus as the lower moors which were crowded with Grouse throughout the winter. The melting of the snow may also have the effect of washing the Strongyle larvae out of the heather. ”

“ When at last a chick is discovered and lifted up in the hand its first "cheep" is the signal for the others to scuttle away out of their places of concealment, or, if they are upwards of a month old, to make their effort at escape by a short flight, after which they are apparently incapable of a second attempt. ”

“ But twenty or thirty other plants are also eaten, often in great quantities, and it is a well ascertained fact that Grouse that have never set eyes upon a sprig of heather will live and flourish for years. Yet the importance of heather in building up the birds for the approach of winter cannot be exaggerated, and there is little doubt that in a bad heather year all the young birds suffer, while even in a good heather year the later broods will be permanently handicapped as regards physique and disease-resisting power if they have missed the best food months. ”

“ Therefore, in the series of skins of cock birds representing the month of April, the great majority are very backward. Healthy birds have still the old, rich, red, copper-coloured throat of the winter plumage, and fresh-looking "autumn" feathers round the neck, upper back, and mantle, while the winter and old autumn plumage of the rump and back is bleached and faded. The backward birds are easily picked out, as they have not yet assumed their "winter" plumage, and are still mostly clad in old, worn autumn plumage of the previous year. ”

“ The mere fact that the crops of many birds contain old heather is enough to prove that birds sometimes find great difficulty in collecting a meal of wholesome food. The vast majority of winter crops contain, as we have already said, good dark green or dark reddish brown winter heather, sound wholesome food with a minimum of dead woody tissue. But now and again one finds a crop full of old woody growth of which the food value must be very small. ”

“ In dissection, the age of an old bird is apparent, perhaps as plainly upon the table as elsewhere. The fibrous tissues all toughen with age and use, and the bones become harder. The grits of the gizzard in an old bird seem to be larger and more worn into rounded pebble shapes, the reason for this has been discussed elsewhere. [6] The question, therefore, of deciding whether a bird is less than a year or more than a year old, is possible, but it seems almost impossible to judge more exactly of the age of an older bird by any sign to be discovered either externally or internally. ”

“ It is thus easier to believe that a sudden check, either by a change of temperature, or by wet and cold, or by want of sunshine, or by change in food, has for the time so far affected the tissue metabolism of the bird that a feather which began to grow upon a circulation lacking pigment particles, and which was therefore originally planned for the paler plumage, may, by a sudden increase in the metabolism of the bird, and so in the output of waste products to the blood, be completed as a feather of the more deeply pigmented plumage, thus producing a feather with the characters of both. ”

“ In one case, however, flooding is a real menace, for if the nesting season is a dry one Grouse have been known to nest in very unsuitable places, such as the beds of burns and dried-up pools and water-courses — often with most disastrous results when the weather breaks.
But, if there has been no rain, the drowning theory must be discarded, and Drought its place is taken by the drought theory; in other words, the fine, dry, warm, sunny weather which is credited with producing a healthy stock in a good year is the cause of their wholesale destruction in a bad year. ”

“ In the first place, it may be stated that it is the young birds rather than the old birds that tend to form into packs in the earlier months of autumn, though the older birds will follow suit as the winter advances. Consequently, when packing first begins, it is the older birds that suffer the greatest loss in a day's Grouse driving, for they come up to the line of butts in twos and threes, and are "mopped up" to a bird, whereas the larger packs of younger birds merely yield a percentage of their numbers to swell the bag. ”

“ The undeveloped ovary of an adult female Grouse would about cover a threepenny piece, but is long and triangular in shape rather than circular. The oviduct in a breeding hen is a large and conspicuous duct, and may, of course, contain an egg with the shell in course of formation, being pigmented in preparation for laying. The oviduct in a barren bird, or in a hen at other times than the breeding season, is a very much less conspicuous object, and is less easily found than the small and undeveloped ovary. ”

“ If we admit that the congestion of a large number of birds upon small areas of moor is conducive to the deposit in dangerous numbers of the larval worms which cause disease on the favourite feeding - grounds of the birds, then it follows that the pack formation is in itself a danger to the health of the stock. This view is supported by the fact that where packing is the exception rather than the rule, as in the west coast of Scotland, disease is of rare occurrence. It is obviously impracticable to induce the Grouse to change this dangerous practice of congregating in packs ”

“ The difficulty in sorting hen Grouse into these classes is that a single bird may fall under three headings at once. A hen Grouse may be at once buff-spotted, white-spotted, and red or black, for the white spotting is an independent character and may occur on any type in the autumn plumage of the breast and abdomen, and this may also be definitely of the red or the black type.
In the Committee's collection, the first or red form is well represented from all parts of the country, and follows very much the same distribution as the red type of the cock Grouse. ”

“ Migration is one of the commonest theories, and is supported by the fact Migration. that few, if any, dead bodies are found on the ground. The migration doctrine presents some difficulties, for the Grouse in its earlier stages is not by nature a wanderer, and a brood is usually found, at all events up to the end of July, not very far from where it was hatched out. Then, again, it is difficult to explain how on a large moor the young birds have departed before they are capable of sustained flight, especially if none of the neighbouring moors have received any noticeable addition to their stock. ”

“ It is interesting, and to some people, such as sportsmen and gamekeepers, even useful to know that bare featherless legs and feet, which have so long been considered a sure sign of disease in the Red Grouse, may, in certain months of the year, be a natural accompaniment of really good health, while thickly feathered legs in the same month are a sure sign of deferred moult and of sickness. ”

“ It might be thought that where a heavy snowstorm occurs during the night there would be a risk of whole packs of Grouse being covered up and smothered by the drifts as the birds were jugging in a sheltered hollow. Sheep are often lost in large numbers by such misadventure, but Grouse never, for as they jug in the lee of a peat-hag or a moorland dyke they tread the snow under them as it falls, and are found next morning safely collected on the surface, though their fresh droppings several feet below show the level at which they began their night's repose. ”

“ Dry ground is always preferred; birds will not nest on boggy or damp ground, and are more likely to leave their nests on account of wet than for any other reason.
On some moors where the heather has been very closely burnt or the stock is unusually large, the Grouse appear to be unable to find nesting ground exactly suited to their requirements, and on these occasions they will boldly depart from their usual habits and will nest in short heather, flat dead bracken, or even on a bare unsheltered piece of burnt ground, leaving the nest as open as that of the Lapwing. ”

“ Although we have no evidence from any one of the hundreds of Grouse crops examined that true frosted heather is ever eaten, the heather which actually filled the majority of the winter crops varied greatly in its value as a food. It could often be seen that the birds had been hard put to it to fill their crops at all, perhaps from stress of weather, or possibly because of excessive or deficient burning or an overstock of sheep, or for some other less obvious reason. ”

“ Even in a young bird the ovary shows ova with sufficient distinctness to make doubt as to its sex an impossibility; but in a very young male bird the testes may be so small, and, being very often black, may look so unlike what is expected that both should be sought for and found before arriving at a certain conclusion as to sex. ”

“ In view of the many dangers to which they are exposed the wild Grouse seldom gets the chance of dying of old age, and the duration of its life depends more on the severity of the shooting and the numbers of vermin than upon the bird's own longevity. ”

“ There are, in the Committee's collection of skins, a number of examples showing the result of disease in deferring the moult; many of these birds, even in October and November, have made no effort to get rid of the old, faded and completely worn-out spring plumage. The majority of these birds have been so diseased in spring that they have not bred at all. The ovaries have throughout the season shown no development, and there are no signs, even in the earlier months, of the shedding or development of ova or of any increase in size of the oviduct. ”

“ Still there remains the difficulty that the dead bodies are not found in any quantity; it must be remembered, however, that the infant Grouse is a small object, and any one who has searched in vain in the heather for a full-grown bird which has fallen to his gun can realise the difficulty of finding a tiny chick upon a moor where the whole stock does not average more than a bird to several acres. Coccidiosis chiefly attacks the birds when they are very small ”