Grouse, including five hundred and forty adult birds of both sexes and forty chicks and pullets. These, however, cannot be taken all together in one Method of
studying
subject. series. It is essential, for purposes of comparison, that the male birds in their two plumages should be taken separately in two lots, and the females in a similar manner. Therefore the skins have to be divided as follows: —
| No. of skins. | |
| Male birds in winter plumage | 241 |
| Male birds in autumn plumage | 120 |
| Female birds in autumn plumage | 108 |
| Female birds in summer plumage | 71 |
| Immature birds of the first six months | 40 |
The largest series of skins is therefore that of the male birds in winter plumage, and it so happens that this set, both as regards sex and plumage, is best adapted by its general uniformity to give some result when arranged map-wise over a large outline of Scotland and England.
An analysis of the greater part of the collection of skins is given in the Table on p. 55.
Having thus arranged the skins into lots which are sufficiently uniform Results of
comparison. to allow of comparison, and having arranged one of these lots, the cocks in their winter plumage, for instance, according to the localities from which they were obtained, it becomes possible to make the following deductions: —
- That the general uniformity is very much more marked than might have been expected considering the character for variability which has always been attributed to the bird; the variability is lost in the mass, though it is visible in individuals.
- That, allowing for a good many exceptions, there is certainly a greater tendency to blackness in the birds of the northern Highlands than in those of the south. Or, one may say that in passing from the north of Scotland southward and westward, there is an increasing tendency to the bright red and dark red types of Grouse, which culminate in the very characteristically bright red bird of Wales and of the Midlands of England, in which the predominating colour of the feathers of the breast and under parts generally is red with
