BRITISH WARBLERS
At such times I have heard them imitate the Whitethroat, Blackbird and Chaffinch, and at other times the Tree Pipit, while once I remember hearing one imitating the call-note of the Partridge perfectly. They can also, when singing, produce a ventriloquistic effect, but do not do so very frequently. The ordinary call-note used by both sexes is a rather harsh crackling note, difficult to describe; the female when mating has rather a different note to the male, and the young when fully grown differ again somewhat from both their parents.
The call-note—this is rather a vague term, in reality meaning very little—is used by both sexes all the summer, and when listening by the side of a reed-bed on hot summer afternoons it is frequently the only expression of bird-life one hears. Thus they keep calling, sometimes with the single note, sometimes with a treble note quickly uttered in a descending scale, as they wander along in search of food, apparently not troubling about an answer to their call, but uttering it mechanically at varying intervals. Any sudden noise or disturbance, even the throwing of a stone into the rushes, is often enough to cause them to sing.
In the latter part of August and the first half of September, that is to say, in the last few weeks before they leave this country, they are much quieter, rarely singing, but instead skulking in the undergrowth, and are therefore difficult to see. As they move about you can hear them occasionally calling to one another, but showing themselves very little, evidently finding plenty of food amongst the stems of the reeds and rushes.
Climatic conditions do not seem to affect them very much, but during very wet weather their song is not so frequent nor so vigorous, neither do they appear to be very happy themselves, but are rather more inclined to mope and are considerably less active.
Their food seems to consist entirely of insects, and during the few months they are with us food of this description is never lacking. They search for it chiefly low down amongst
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