Upper parts olive-green tinged with yellow; above the eyes a narrow, faint, yellowish, white streak; under parts yellowish white; feathers of the leg dirty white; second primary equal to the seventh; third, fourth, fifth, and sixth with the outer web sloped off at the extremity; under wing-coverts primrose-yellow; feet slender; legs nearly black. Length four inches and a half; breadth seven and a quarter. Eggs white, sparingly spotted with dark purple.
Whatever question there may be whether the name of Willow-warbler be appropriately applied to the last species, there can be no doubt that the Chiff-chaff is well named. Let any one be asked in the month of May to walk into a wood and to hold up his hand when he heard a bird call itself by its own name, 'Chiff-chaff', he could not possibly fall into an error. The bird is so common that it would be difficult to walk a mile in a woodland district without passing near one or more, and having little to say, it seems never weary of repeating its tale, 'Chiff, chaff, cheff, chiff, chaff': the syllables have a harsh sound pronounced by human lips, but when chanted in the silvery notes of a little bird, in the season of primroses and wild hyacinths, and accompanied by the warble of the Hay-bird, the full song of the Thrush, and the whistle of the Blackbird, they contribute not a little to the harmony of the woods.
For two successive years a little yellowish bird, scarcely bigger than a wren, has established himself in my garden about the middle of April, and sedulously devoted himself to clearing away the aphides which infested some China roses trained against the walls of my house. Occasionally he would flutter against the windows, and give his attention to the spiders and gnats which nestled in the corners of the panes. The first year I took him for a Hay-bird, but, only too grateful for his kind offices, I was careful not to molest him. When, however, he appeared a second year, exactly at the same season, and performed a series of manoeuvres so precisely similar that it was impossible to doubt that the bird was not merely of the same species, but the same individual, I watched him more closely. The dark colour of his feet, as observed from within the house, as he was fluttering against the glass, decided the point that he was not a Hay-bird, and when he retired to an apple-tree hard by and treated himself to a song after his repast, no doubt remained that he was a Chiff-chaff. It is not often that the Chiff-chaff is thus familiar in its habits. More frequently it makes its abode in woods and groves, resembling the Hay-bird so closely in size, colour and habits, that to distinguish the two is very difficult. The difference of note, however, is decisive; and the colour of the feet (when the bird is near enough to admit of being thus distinguished) is another certain criterion. The two birds frequent the same trees without rivalry or jealousy. The Chiff-chaff is the earliest of our spring visitors, arriving the middle of March, and it sings all through the summer; I have heard it as late as the thirtieth of September. The nests, popularly called 'wood-ovens', are alike and placed in similar situations; their eggs are of the same size and shape, but those of the Chiff-chaff are spotted with very dark purple instead of rust colour. A few occasionally remain with us all the year, feeding on winter gnats and the pupæ of small insects, but remaining wholly silent. Other names by which it is known are 'Chip-chop' and Lesser Pettichaps.