To return to the Reed Warbler. The females often commence to arrive shortly after the first males, but how soon after depends upon whether the arrival of those males was an early one or the reverse. They are seldom in evidence before the middle of May, so that if a male arrived at the very commencement of that month, fully a fortnight might elapse before pairing commenced. As already mentioned, the period of migration of both sexes is spread over a considerable time. The female that arrived on June 21st must still be regarded as a migrant, although it is quite possible that this particular bird, as also, perhaps, many of the males that are very late in arriving, was only a wanderer in this country, not a true migrant in the sense of having only recently completed its migratory journey. However, it is quite impossible to decide this; the wandering males may only be the individuals that have been unsuccessful in securing a territory, the wandering females those that have been unsuccessful in finding an unmated male in possession of a territory. The fact of these observations having been made in the centre of England makes such a contingency more possible than if they had been made on the south or south-east coast. But whether it be the case or not, it is evident that solitary males, forerunners of the migratory movement, are the first to reach this country, and in this respect the species resembles other migratory species. The interval between the arrival of the first male and the first female may vary in different species; and, if this is so, we should expect it to be of shorter duration in the case of those species that are accustomed to reach this country in May than in those that face the cold winds of March.
The period of sexual activity is disappointing so far as the attitudes assumed are concerned. There is no abnormal waving of the wings and spreading of the tail, which is characteristic of so many species. We may say that the nervous organisation of the bird is not so highly developed as that of some others, and thus attempt to account for the difference, but this does not take us very far towards a