Its food consists almost entirely of small flies, caterpillars, and other insects, which it captures among the branches and leaves of the trees, rarely descending to the ground. Two broods are reared in the season and the rest of the summer is spent quietly and unobtrusively till, in October, the first storms of winter and growing scarcity of food compel it to retire southwards. This it does reluctantly, and a certain number spend the winter in the milder climate of Devon and Cornwall. The upper parts are olive green; wing coverts, quills, and tail feathers brown, edged with the same colour. Under parts whitish. There is a pale yellowish white streak above the eye. The sexes are alike in plumage and the young are slightly greener. Length 4·6 in.; wing 2·35 in. This species may be distinguished from the Willow Wren by its smaller size and darker legs. The second quill is equal to the seventh and the outer webs are emarginated near their tips up to and including the sixth. In the Willow Wren the emargination only reaches the fifth and the second is equal in length to the sixth. It should be remembered that the first quill is very short and inconspicuous, so that the first apparent quill is the second. This species is scarcer and more local than the Willow Wren. In Scotland it is local and is only a straggler to the north of that country and the surrounding islands. THE SIBERIAN CHIFFCHAFF Phylloscopus tristis, Blyth One example of this small warbler, that breeds in Western Siberia, migrating to Turkestan and India in winter, was obtained at a lighthouse off the Orkneys in 1902. It is rather smaller and browner than our common Chiffchaff and has the under parts buffish white. It may, however, always be recognised by the shortness of the second primary, which comes between the seventh and the eighth, or is even shorter than the eighth. [Illustration: CHIFFCHAFF _Phylloscopus collybita_ [Vieillot] (above) WILLOW WREN _Phylloscopus trochilus_ (below)] THE WILLOW WREN Phylloscopus trochilus (Linnæus)