Page:The British Warblers A History with Problems of Their Lives - 8 of 9.djvu/16

 regarding the hours of darkness as the period of maximum activity so far as movement from place to place is concerned. We can observe but little trace of fatigue in these smaller migrants. One would expect to find evidence of the long journey—to see travel-stained, weary individuals—but, excepting in isolated cases which occur for the most part amongst those species which face the storms of early spring, the majority of the newcomers are on arrival just as vigorous as they are a week or so later, neither do they show by their plumage any trace of the difficulties through which they have passed. The male awaits the arrival of a female in his territory, and until she appears upon the scene passes the greater part of his time in song or in searching for food. He wanders restlessly around his territory, but his wanderings are subject to that routine which is a peculiarity of so many species. A habit is thus formed in his journeyings backwards and forwards. Time after time one can observe the same tree or bush searched for food and the same line of flight taken between the various trees. A certain tree or clump of trees is often especially favoured and used as a headquarters, from which he proclaims his presence by song. The territories vary in size according to the nature of the environment in which they are situated, and according, I fancy, to the numerical standing of the species in the particular locality. In large woods they are often extensive, but in osier beds and plantations considerably smaller; in the former case the wanderings of the male may cover as much as five acres of woodland, in the latter the bird has to be content with an acre or even less. Where the birds are numerous and territories adjoin one another, it is evident that the movements of the males must be restricted; the dimensions therefore become regulated automatically, and are no doubt reduced to the minimum size necessary for the welfare of the species. With regard to the initial struggles between the males touching the question of territory, I have little evidence. The females follow so