44 DISPOSITION TO SECURE A TERRITORY 



culties of the males there similarly situated ; 

 and even allowing that they are at length 

 successful in establishing themselves, what 

 are their prospects of securing mates ? Since 

 the earlier females will not extend their wander- 

 ings farther than is absolutely necessary, but 

 will pair whenever the opportunity for doing 

 so arises, it is to the later females, forced 

 onwards by competition, that the late males 

 must look for mates ; so that when at length 

 pairing does take place, much valuable time 

 will have been lost. 



The disadvantages which the late arrivals 

 have to face are therefore great, and it is 

 probable that the percentage which attain to 

 reproduction will on the average be somewhat 

 lower than the percentage in the case of the 

 earlier arrivals. The district in which my 

 observations have been made lies well within 

 the limits of the breeding range of most of 

 our common species, and it is not surprising 

 that I should have met with little evidence 

 of failure to breed as a result of failure to 

 secure territory. Some interesting information 

 was supplied to me, however, by the late 

 Robert Service. He found, in certain seasons 

 in Dumfriesshire, flocks of from ten to fifty 

 unmated Sedge- Warblers, which, from the time 

 of their arrival in May until the middle of 

 July, haunted reed-filled spaces along stagnant 

 streams. These flocks appeared to him to be 

 composed of loosely-attached individuals of 

 a migrant flock that had failed to find things 



