CLASSIFICATION AND LIFE HISTORY 9 



ment of thirty-six eggs as 45 '56 by 31 '8 mm., and the average 

 weight of eight eggs as T845 g." 1 



There is no truth in the belief that disease will follow if 

 the eggs are not well coloured. Very often the uncoloured 

 part of the egg whitens at the same time as the coloured part 

 fades or is washed off, thus making an egg of " bad colour." 



It is interesting to note that a bird of five years old lays 

 fewer eggs and of a smaller size than a bird of one or two years 

 old. 



The net yield of the nesting season greatly depends upon 

 the weather in spring ; frost before sitting, snow after hatching, 

 heavy rain following a drought when the birds have nested 

 in low-lying ground liable to submersion, are some of the 

 principal dangers to which early broods are exposed. The 

 eggs also may be lost by a long spell of wet weather, even up 

 to the point of hatching. This is probably not a matter of 

 common occurrence, but in the spring of 1906 the Committee's 

 field observer saw nest after nest deserted owing to rain. The 

 nests on the low ground fared worst ; in some the eggs did 

 not hatch at all, in others only one half, or even fewer, were 

 productive. 



The parent birds seem to defy the elements at all times, --^Nesting 

 and during the period of incubation the hen will continue to f " 

 sit upon her eggs apparently oblivious of the fact that a snow- 

 storm is raging which has driven every other living creature 

 off the moor. During such a storm hens are sometimes com- 

 pletely covered with snow as they sit upon the nest, for in hard 

 weather instinct teaches them not to desert the post of duty. 

 Observation of the bird at these times is difficult, fcr even the 

 most enthusiastic naturalist is not often tempted to explore 

 the higher ranges of the ground in the face of a blinding blizzard. 

 We must to some extent form our conclusions by observation 

 of after-results, and certainly there is little doubt that the effect 



1 Dresser's " Eggs of the Birds of Europe," p. 623, PI. LXVII., Fig. 1. London: 

 published for the author at the Office of the Royal Society for the Protection of Birds, 

 3 Hanover Square, 1905-1910. 



