the middle of July. This. I think, may often be an explanation of the quarrelling; but without further observation it would be unwise to speculate upon the cause of the gathering together of different individuals, of the spontaneous outburst of song, and of the pursuits, which possibly are not in earnest.
Quarrels between this species and Sedge Warblers are not uncommon, sometimes one being the aggressor, sometimes the other. They dart at one another with the usual clicking of bills; and of the two the Eeed Warbler seems to be the stronger. But I have seen a male Sedge Warbler interfere in a most unjustifiable manner. This particular male owned a territory in some alders adjoining the reeds, and, as is their wont, favoured one particular tree, from which he constantly performed the aerial flight and song peculiar to the species. Now a pair of Eeed Warblers were located some little distance away, and, as if for pure enjoyment, he would suddenly anddart at one or other of them, pursuing it amongst the reeds and thus causing considerable commotion. There was no obvious reason for such behaviour, unless we regard it solely as practice for the more serious side of its existence, that is to say, the necessary defence, which might at any moment arise, of its territory.
Few birds sing under smaller provocation. Even a stone thrown into the reeds is often sufficient, and the advent of a Jay (Garrulus glandarius), or a Magpie (Pica rustica) will sometimes produce a spontaneous outburst in which the majority of the males take part. The spontaneity with which these outbursts occur is very striking. One, or perhaps two, males may be leisurely singing, when suddenly, and often for no apparent reason, all the males burst into their hurried excitable song for a few moments only, and then again lapse into silence. The song in which the female occasionally indulges is peculiar, and differs in this respect from that of all other members of the genus, excepting the Great Reed Warbler (Acrocephalus turdoides), that it does not flow evenly from