SEPTEMBER. 167 



thrush or sparrow has very little chance of coming to 

 maturity, for its change of colour renders it especially 

 conspicuous to its enemies, and it is harried continually 

 and eventually destroyed. But in this favoured land if 

 the young bird escapes the attention of that most destruc- 

 tive animal the small boy, its only enemies are those of its 

 own kind. Apparently these are often formidable enough, 

 for there is no such thing as fashion in Nature, and a 

 thrush which develops a white wing or a white - striped 

 tail, instead of being admired by all other thrushes, is 

 treated more or less as an anomaly as having transgressed 

 the laws of proper and sober thrush colouring, and is liable 

 to be treated with contumely. The fable of the fox 

 without a tail appears to receive a great deal of exemplifi- 

 cation among the higher animals, and the harsh treatment 

 often meted out to what are known as "sports" in a state 

 of Nature is probably one of the devices whereby specific 

 characters are safeguarded from indiscriminate variation. 

 I formerly collected a good deal of information about such 

 sports among our introduced birds, and found that while 

 they were fairly common yet they did not tend to increase 

 much, except in special localities. For several years there 

 used to be broods of thrushes in the Town Belt and 

 gardens at the foot of Littlebourne which had either- 

 white wings or tail, or both, but I saw none last season. 

 Mr R. M. Laing has told me that in one portion of Christ- 

 church white-feathered and very light-coloured sparrows 

 were becoming common. This was several years ago, and 

 if such sports are anywhere tending to become permanent 

 an interval of a few years would give them time to assume 

 a marked character. I have always noticed that such 

 conspicuously-coloured birds were unusually wild and shy, 

 their markings making them objects of undesirable atten- 

 tion to various kinds of bipeds. 



This fact of colour-variations among birds tending to be 

 so constantly eliminated may account for the uniformity 

 of colour which characterises the individuals of the various 

 species. In the case of rabbits there appears to be no 

 repression of the tendency to vary, nothing to repress the 



