The sedge-warbler, usually called sedge-bird, and in some localities river-chat, is a common species in most waterside places where there are reed-beds and willows; it also frequents rough hedges and bramble and furze bushes in the neighbourhood of a watercourse. Sometimes, but not often, it is found breeding at a considerable distance from a stream. It comes to us in April, and is a most active and lively little creature. Although not shy of man, it is less easy to observe than any other species in this group, except, perhaps, the grasshopper warbler, on account of its excessive restlessness, the rapidity of its movements, and its habit of keeping near the surface in the close reeds and bushes it lives in. The grasshopper warbler, and, indeed, most small birds that inhabit bushes, love to come to the surface to sing; the sedge-warbler sings much as he hurries about in search of his food, which consists of small caterpillars and slugs, and aquatic insects. Occasionally the restless little yellowish brown figure appears for a moment or two near the top of a bush, and then vanishes again.
The song is curious, and delivered in a curious manner, with hurry and vehemence; and this, as well as the character of the sounds emitted, gives the idea that the bird is excited to anger—that he is scolding at, rather than singing to, the listener. The opening note, hurriedly repeated several times, and recurring at short intervals as long as the song lasts (its keynote and refrain), resembles the chiding note of the whitethroat when its nest is approached, but is louder and more strident. It is the loudest sound the sedge-warbler emits, and when the song is heard at a distance of fifty or sixty yards it seems all composed of chiding notes. But on a nearer approach—and the bird will allow the listener to get quite close to it—the performance is found to be a very varied one. Listening to it, one finds it hard not to believe that this warbler possesses the faculty it has often been credited with, of mocking other species. But if he indeed has such a talent, he reproduces not so much the songs of other birds as the notes and chirps and small cries of anxiety and alarm—the various sounds emitted by singing-birds in the presence of danger to their young or incubated eggs. Thus, in the medley of hurried and strongly contrasted sounds that come in a continuous stream from the sedge-warbler one seems to recognise the low girding of the nightingale, and the different notes of solicitude of the sparrow, reed-bunting, and chaffinch, of the wren and the willow-wren, the meadow-pipit and pied wagtail. But whether these various sounds are really borrowed or not one can never feel sure.
The sedge-warbler is a very persistent singer. Some birds are too chary of their strains; but of this waterside music any person may have as much as he likes in May and June. Singing is apparently as little tiring to this bird as rushing through the air is to the swift. At the season of his greatest vigour he appears to pour out his rapid notes almost automatically; and when silent, a stone or stick flung into his haunts will provoke a fresh outburst of melody. He also sings a great deal at night in the love season.
The sedge-warbler makes its nest among the tangled vegetation at the waterside; as a rule it is placed near the ground, and is composed outwardly of moss, leaves, and aquatic grasses, and lined with fine grass and hair. The eggs are five, of a dirty white or pale brownish ground-colour, with yellowish brown spots, sometimes with hair-like marks among the spots.
Besides the two described, three more species of this group of warblers have been numbered as British birds, having been found as stragglers in this country. These are the marsh-warbler (Acrocephalus palustris), the great reed-warbler (Acrocephalus turdoïdes), and the aquatic warbler (Acrocephalus aquaticus).
Grasshopper Warbler.
Locustella nævia.
Upper parts light greenish brown; the middle of each feather, being darker, gives a mottled appearance; under parts very pale brown, spotted with darker brown on neck and breast; feet light brown. Length, five and a half inches. Female without the brown spots on the breast.
This warbler arrives in our country about the middle of April, sometimes a week, or even a fortnight, earlier. In the melodious family to which it belongs it is distinguished by the singularity of its voice, which has no musical, or song-like, or even bird-like quality in it, but is like the sound produced by some stridulating insects. It is to be found in suitable situations throughout England and Wales, and in many parts of Scotland and Ireland. It frequents both dry and marshy ground where dense masses of vegetation afford it the close cover which would seem necessary to its frail existence; thus it is found in reed-beds growing in the water, and in hedges and thorny thickets, and among the furze-bushes on open commons. Although thus widely distributed in the British Islands, it is, like the nightingale, very local, and reappears faithfully each spring at the same spot. How strong the attachment to place, or home, is in this species will be seen in the following fact: Having found a small colony of about half a dozen grasshopper warblers inhabiting a circumscribed spot in the middle of an extensive common, I went back to the place in three consecutive summers, and each time found the birds in the same bushes. Yet the dozen or twenty furze and bramble bushes which they inhabited were in no way, that one could see, better suited to their requirements than hundreds of other bushes of the same description scattered over the surrounding land. Nor were any other individuals of the species to be found in the neighbourhood, except one pair, which were always to be met with in some brambles about a quarter of a mile from the spot inhabited by the other birds. Such a fact appears to show that, not only do the old birds return year after year to the same breeding-place, but that the young also come back to the spot where they were hatched; also, it appears to show that in this frail and far-travelling species the annual increase is only sufficient to make good the losses from all natural causes.