The willow-wren breeds early, making a circular domed nest on the ground, among the long grass and weeds, under a hedge or beneath a bramble bush on a bank, and occasionally at a distance from sheltering bushes in the grass of a field. It is made of dry grass, and lined with rootlets and horsehair, and, lastly, with feathers. The eggs are six or seven in number, pure white, the yolk showing through the frail shell, and giving it a faint yellow tinge; they are blotched and spotted with reddish brown. When the nest is approached the parent birds display the greatest anxiety, hopping and flitting about close to the intruder, and uttering low, plaintive notes.
The willow-wren stays longer with us than any migratory warbler except the chiffchaff, and its song is, without exception, the most persistent. From the time of its arrival in March, or early in April, it sings without ceasing until July; then for a few weeks its song is heard only in the early morning, and it ceases at the end of August, during the moult, but is renewed a little later, and is then continued until the bird’s departure at the end of September.
Wood-Wren.
Phylloscopus sibilatrix.
Upper plumage olive-green tinged with sulphur-yellow; a broad streak of sulphur-yellow over the eye; sides of head, throat, and insertion of the wings and throat bright yellow; rest of under plumage pure white. Length, nearly six inches.
This warbler arrives in England at the end of April, being later by many days than its two nearest relations, the chiffchaff and willow-wren. As its name implies, it is a bird of the woods, with a preference for such as are composed wholly or in part of oak and beech trees. It is not easily discerned, on account of its restless disposition; also because it chiefly frequents the uppermost parts of the trees it inhabits. Its instinct appears to be to live and hunt for the small insects it preys on among the green leaves at the greatest possible height from the earth; this may account for its love of the beech, which is the tallest of our forest trees. But if difficult to see as it flits lightly from place to place among the higher foliage, it is easy to hear, and its frequently uttered song sounds very loud in the woodland silence, and is strangely unlike that of any other songster. It may be said to possess two distinct songs: of these, the most frequently uttered and unmistakable begins with notes clear, sweet, and distinct, but following more and more rapidly until they run together in a resonant trill, and finally end in a long, tremulous note, somewhat thin and reedy in sound. At longer intervals it utters its other song, or call, a loud, clear note, slightly modulated, and somewhat plaintive, repeated without variation three or four times.
The wood-wren, although so great a lover of the tall tree-tops, breeds on the ground, like the two species described before it, and, like them, builds an oval-shaped domed nest. It is placed among the herbage, and is composed of moss, dry leaves, and grasses, lined with fine grass and horsehair. Feathers are never used in the nest-lining, and in this the wood-wren differs from the two preceding species. Six eggs are laid, transparent white, spotted and speckled with dark brown, purple and grey.
The wood-wren differs from most of the warblers in being exclusively an insect-eater.
A fourth member of this genus, the yellow-browed warbler (Phylloscopus superciliosus), which breeds in Northern Siberia, has been met with as a rare straggler in this country.