BEITISH WARBLERS 



the Chaffinch, and, in the case of the latter species, the 

 females struggle fiercely together, their battles being as 

 desperate as those which occur between the males. I have 

 seen two individuals struggling intermittently for nearly half 

 an hour, and for the greater part of that time the fighting took 

 place on or near to the ground. There was no doubt that 

 the conflict was genuine ; the rapid breathing, tightly drawn 

 feathers, the rolling over and over on the ground, and 

 the fluttering up in the air, showed this only too plainly. 

 The male watched the contest from a branch above, and 

 occasionally interfered by flying into the arena, but whether 

 he attacked one bird only I was unable to ascertain; his 

 efforts were of little avail in putting an end to the battle. 

 This, then, is the sum-total of the evidence — insufficient, 

 perhaps, to justify any definite conclusion ; and there for the 

 present we must leave it. But if there be any who think the 

 evidence unreasonably scanty, supposing the struggles of the 

 females to be a reality, I would ask them to consider this 

 point — one to which I shall presently refer with regard to the 

 males — that it is unnecessary for every individual to struggle 

 for a territory, and this must be even more true of the females. 

 It is not necessary, neither is it possible, for each female to 

 have a rival for the territory in which she has settled. Prob- 

 ably it will only occasionally happen that two females meet 

 in competition in any one particular locality, but if, when they 

 do so meet, the stronger gains an advantage, that is all that 

 will be required to maintain the strength of the species. 



Our confidence in the truth of a theory must increase in 

 proportion to the number of observations which receive an 

 explanation under that theory, but not under any other. And 

 there are two observations which become intelligible under the 

 theory of breeding territory, but which, hitherto, have been 

 inexplicable. The first of these, and the more important, is 

 the fact of the males arriving at their breeding haunts before 

 the females. It has long been recognised that amongst the 

 migrants the first individuals to reach their destination in the 



16 



