Page:The British Warblers A History with Problems of Their Lives - 4 of 9.djvu/68

 sometimes sit opposite to one another and bow in rather a curious manner, the feathers on their heads being erected and their tails outspread. One will suddenly commence to utter its harsh call note, and this is a signal for a number of them to collect and pursue each other vigorously, their whole demeanour being very much like that of the Blackcap.

During September their numbers gradually decrease, and towards the end of that month the majority have left this country, though solitary individuals still remain until the early days of October. Their food is similar to that of the Whitethroat.

The song itself requires little description. It is by no means so highly developed a production as that of the Whitethroat. When the males first reach us in the spring they sing incessantly as they travel in search of food, but after the females arrive they are more silent than many other species, though solitary individuals can be heard warbling even as late as the end of June. Of imitation there is very little; I can only recollect hearing two species copied, i.e., the Linnet and Sedge Warbler, and this was during a male's excitement at the presence of another male before the females had arrived. The song itself varies considerably in different countries and even in different districts. When in Hungary I pursued a male, which was singing continuously, for some distance before I discovered to what species the owner of the voice belonged.

This local variation is a curious and marked feature of the song of many birds. For some years I was conscious of a difference in the song of individuals of the same species in districts not far apart, but until I commenced to keep records, and make mental comparisons in different and widely separated localities. I did not realise to what an extent this local variation existed, and I was certainly not prepared to find so astonishing a divergence in the song of one and the same species.

The Whitethroat that enlivens the roads and lanes of our Midland counties has a different voice from the Whitethroat