BRITISH WARBLERS
especially when he will do nothing but whisper, for this ventriloquistic effect is not so marked when singing loudly. Until pairing has taken place the song is almost incessant, morning and evening, rare during the daytime, more frequent at night; afterwards, and until the young are able to take care of themselves, it almost ceases, until it becomes a mere apology of the song of the mating season, often reduced to a few crackling notes, heard on a hot afternoon or during the first hour or so of dawn. To this partial cessation of the song may possibly be traced the belief that in certain districts the birds do not stop to breed, but are only to be found on their way to their breeding quarters; yet it is characteristic of many of the warblers, but perhaps more marked in the one under consideration; and thus the theory of the male lightening the female's task of incubation by song becomes a fanciful one, having little foundation of fact to recommend it, and against it the weighty evidence of Nature who always strives for a more complete concealment of her children. Before the arrival of the females, the males during the first few hours of daylight are very fond of playing with one another; and although their games are not to us very interesting, yet considerable energy is expended on them by the birds themselves. One male darts off after another one, pursuing him with very rapid flight into some thick bush; here he chases him up and down and along the branches with tail outspread and wings extended and slowly flapping, his behaviour being exactly similar to that during courtship, occasionally making use of a very curious note, much like the scolding of the Garden Warbler (Sylvia hortensis) when its nest is approached; and this sound appears to be produced with considerable exertion.
On the arrival of the females, about April 27th, ten days or so after the males, the courtship is immediately commenced. No period in the life-history of the individuals of any species is so interesting to watch or so full of significance as this. Every nerve is strained to a degree which makes incidents in
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