Page:The British Warblers A History with Problems of Their Lives - 5 of 9.djvu/20

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worn or ragged appearance, but the colouring is brilliant and the feathers in perfect condition, in striking contrast with those birds that have actually commenced to breed some weeks previously. The deterioration of the plumage is coincident with, if not actually the direct result of, coition, for it takes place very slowly when a bird is not breeding, but rapidly immediately reproduction has commenced. Nevertheless evidence of a much more detailed character is necessary before we can reach a final decision on this point. It even appears to be more rapid in some species than in others, being decidedly so in the case of this warbler, some individuals commencing their moult early in July. So that we find, on the one hand, members of the species arriving about June 20th in perfect plumage, and thereupon commencing to breed, and on the other, members commencing to moult early in July, having finished the task of reproduction. Thus we have what appears to be a curious irregularity, and one to which I shall refer again.

The Arundo phragmites is the principal but not the sole haunt of these birds, for they often frequent and build amongst the various species of Salix that grow along the banks of rivers, and on their way thither, or when in search of a territory, the males sometimes rest for a few days, or a few hours, in such places as osier beds, or even amongst the shrubs in gardens; but in such places they are merely sojourners, although they sing as vigorously as if they were in possession of a territory. They commence to sing on the morning after their arrival, and as they are the most persistent of singers, there is little difficulty in assuring oneself of their presence in any particular reed bed. This is especially the case before the females arrive, as they then sing almost incessantly throughout the first few hours of daylight, commencing at dawn and only lapsing into silence for short intervals. At this time of day they can often be seen perched on some horizontal reed pouring out their peculiar metallic sounding notes, or preening their feathers, their attitude at such a time being much like