150 BIRD HAUNTS AND NATURE MEMORIES 



be noticed. But when the average results are considered 

 the final doom is always the same all but two of the hope- 

 fuls must go to the wall. 



A pair of birds may lay an average of four eggs per year 

 for three years; ten out of twelve produced must have 

 negative results; the young if hatched and reared must 

 never become parents, or if more than the two survive 

 in many of the same species we shall at once have a notice- 

 able increase. A small steady increase in the families 

 descended from one pair of birds will, in a few years' time, 

 mean a vast army; any mathematician can demonstrate 

 that. And what does happen when this occurs? for it 

 does constantly in certain species. Simply this, that the 

 joy and success of one species spells sorrow and failure 

 for others. The supply of victuals, whether animal or 

 vegetable, of each species is not illimitable, and when your 

 successful species gets to grips with others the weaker 

 kinds suffer famine. How often do we deplore the 

 decrease, say, of the woodpecker, the chough, the 

 swallow. Do we ever think that there may be any 

 connection between this and the increases we welcome 

 of starling, jackdaw, swift ? That these particular species 

 mentioned have any interdependence is mere theory, 

 and the whole skein is so ravelled that we cannot disen- 

 tangle its intricate meshes; but there is connection 

 between all increases and decreases. By no means is it 

 certain that the improved breech-loader explains the 

 absence of the great bustard from our open plains, or that 

 the egg-collector wiped out Savi's warbler and threatens 

 the Kentish plover and Dartford warbler; men, in their 

 greed, help to destroy the struggling species, and there is no 

 excuse for this rapacity; but these were struggling when 

 man took a hand in their final extinction. The red-legged 

 partridge, a hungry alien, the go-ahead reed warbler, the 

 ringed plover, and even the willow wren, may have 



