solution. If we thoroughly understood the development of the sexual organs and the influences exerted thereby, the explanation of these activities might be less of a mystery than it is at the present time.
The unemotional behaviour of the male Reed Warbler at this period is, then, very striking. He follows the female closely from place to place as she wanders about his territory, giving expression to his feelings by occasionally bursting into song, or by flying at and playing with her, fluttering amongst or over the tops of the reeds, sometimes even pursuing her rapidly. In the moments of extreme excitement he sings rapidly, raising the feathers on his head and back, and loosely fluffing out those on his breast and flanks while doing so. He also spreads his tail, and slightly raises or rather jerks his wings. Once only have I seen a male, previous to the actual construction of the nest, carry, while following his mate, some material in his bill, and in this instance he appeared to be carrying some seeds of the bulrush. How far the duration of the period of sexual activity varies in the case of different individual pairs I am unable to say. But it is not very probable that the species differs in this respect from others. Judging from those instances which I have had under my notice from the commencement of the breeding season, this period would seem to be of short duration, for the nest in one case was actually commenced the very morning upon which the female arrived. Although the male sings frequently when following the female, yet his song is not so persistent as prior to her arrival. The male that had his headquarters in the salix bush sang morning after morning for a whole month until a female arrived, when he almost deserted the bush and became comparatively silent.
The nest, when built amongst the common reed, is suspended from stems varying in number from three to seven, but it is sometimes placed in a young alder tree (Alnus glutinosa) not more than 5 ft, in height, or even amongst the branches of willows. But this latter situation seems to be resorted to when