176 TERRITORY AND REPRODUCTION 



has led to, the evolution of the territory. Thus, 

 in many cases, we find that early mating is the 

 rule rather than the exception ; we find that the 

 sexes frequently separate to seek their food, and 

 fly away temporarily in different directions ; 

 and, under exceptional climatic conditions, we 

 find that they even revert to their winter routine 

 and form flocks ; only, however, to return to 

 their territories, as pairs, under more congenial 

 conditions. Yellow Buntings, for example, pair 

 comparatively early in the season some in the 

 latter part of February, others in March, and 

 others again in April ; and some build their 

 nests in April, others in May. There is a gorse- 

 covered common which I have in mind, a 

 favourite breeding resort of this species. 

 Between this common and the surrounding 

 country, the birds constantly pass to and fro. 

 If you watch a particular male you will observe 

 that it sings for a while in its territory, that it 

 then rises in the air and disappears from view, 

 and finally that it returns to the tree, bush, or 

 mound which constitutes its headquarters, where 

 it again sings. Meanwhile the female, with 

 which there is every reason to believe that this 

 male has paired, behaves similarly ; she, too, flies 

 to the surrounding country and in time returns 

 with equal certainty. Sometimes male and 

 female accompany one another that is, they 

 leave simultaneously and likewise return ; at 

 other times, though they depart together, the 

 male returns alone ; or the male may disappear 

 in one direction whilst the female does so in 



