Page:GrouseinHealthVol1.djvu/40

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12
THE GROUSE IN HEALTH AND IN DISEASE.

seldom support their statement by pointing out nests deserted by the hen after being buried in the snow, they keep the plausible explanation ready for use if required, and if the stock after all proves to be up to the average, they feel secretly rather surprised, but say nothing about the adverse conditions in the breeding season, for the excuse may be required the following spring. Thus much valuable evidence is lost owing to the very natural desire of the gamekeeper to prove himself the innocent victim of circumstances.

Obviously, if the occasional snowstorms and moderate frosts of a normal April were really responsible for the damage so often attributed to them, it would follow that in a really inclement nesting season, such as occurred in 1908, the effects would have been disastrous throughout the length and breadth of the country. As a matter of fact, the bags in the autumn of that year, though unequal, were well up to, and in some places far above the average; and even where a shortage of birds was reported the failure could often be traced to other causes than the unfavourable weather-conditions in the spring.

While the evidence collected does not confirm the view that snow and frost in the nesting season are extensively destructive to the eggs of Grouse, there is Interruption
of
breeding
by bad
weather.
some reason to believe that unfavourable weather, occurring immediately before the date of laying, has an injurious effect upon the breeding by power of the parent birds. In the spring of 1908, for example, it was observed that on many moors birds which had paired, and were about to nest, became packed again on the arrival of frost and snow, and postponed their breeding operations until some time after the return of favourable conditions. The result was that they nested several weeks later than they would otherwise have done, and not only were their broods late, but the number of eggs laid was smaller than usual — sometimes averaging only four and five in a nest. The resulting smallness of the coveys was often accounted for by the hypothesis that several eggs in each nest had been destroyed by the frost in April; but there was little direct evidence of this, and it seems equally reasonable to suppose that the power of egg production had been impaired by the enforced postponement of nesting. The data are insufficient to establish this theory, but the point is worthy of a passing mention.

It is certain that some of the eggs were lost owing to their having been dropped on the snow and not in a nest at all. After a certain stage of development the egg is laid wherever the bird happens to be. It is not uncommon to find eggs dropped in this accidental manner lying on the ground or on snow.