44 



The Irish Natural ht. 



May, 



lierself . The two lighting birds sit backwards in the water 

 and strike out at one another with their two feet. 



Both these examples therefore strengthen the ground 

 for maintaining that nuptial colour is only another name 

 for war-paint. 



But how do I explain, on this principle, the extension 

 of these warning colours, in a considerable number of cases, 

 to the females ? Why, especially, is this so generally true 

 of birds that nest in holes ? These are the cases that 

 Dr. Wallace quite easily explains by saying the hen birds 

 that nest in holes are in no need of protective coloration 

 while sitting on their eggs. But his explanation seems to 

 assume that the only use of protective colour to most 

 birds is to hide them when they are sitting on their eggs. 

 This, I think, is claiming both too much and too little for 

 the principle of protective colour : too little, because it is 

 certainly useful to many birds to be inconspicuous at other 

 times than when hatching, and too much, because as a 

 rule the nests of birds are not so very badly hidden as to 

 expose the hatching bird easily to view, whether her colours 

 are bright or dull. It is well known that in a great many 

 species the cock takes his turn at hatching, and I have 

 never heard of a case in which this masculine indiscretion 

 was the cause of the nest being found. So I don't think 

 Wallace's explanation is so perfectl}- satisfactory as to 

 prevent our looking for others ; and it seems to me that 

 the doctrine of Warning Coloration is that which best 

 meets the facts. 



The warning colours and warning notes of birds that 

 build in the open, and that possess separate nesting areas 

 for each individual pair, are challenges addressed only, as 

 a rule, to other birds of the same species — because a 

 Blackbird does not object to a Hedge-Sparrow nesting 

 and singing within his domain, nor does a Greenfinch resent 

 the presence of a Yellow-hammer, or a Whitethroat care 

 to disturb a Wren. The battles of the nuptial season are 

 therefore, for these birds, battles bc^tween antagonists of tlie 

 same species — Chafiinch against Chaffinch, Wren against 

 Wren, ajid s<> on. In su(4i cases it is jiatiu'al that the 

 cocks sliould be K'H to do Uiv lighting. To let the hens 



