Mountain chiffchaff Caucasus, but interbreeding occurs rarely, if ever. The mountain chiffchaff differs from "tristis" in vocalisations, external morphology and mtDNA sequences. Its two subspecies appear to be distinct vocally, and also show some difference in mtDNA sequences. Mountain chiffchaff The mountain chiffchaff or eastern chiffchaff ("Phylloscopus sindianus") is a species of leaf warbler found in the Caucasus ("P. s. lorenzii") and Himalayas ("P. s. sindianus"), and is an altitudinal migrant, moving to lower levels in winter. The nominate subspecies is similar to the Siberian chiffchaff, but with a finer darker bill, browner upperparts and buff flanks; its song is almost identical
Common chiffchaff and larvae of butterflies and moths, particularly those of the winter moth. The chiffchaff has been estimated to require about one-third of its weight in insects daily, and it feeds almost continuously in the autumn to put on extra fat as fuel for the long migration flight. As with most small birds, mortality in the first year of life is high, but adults aged three to four years are regularly recorded, and the record is more than seven years. Eggs, chicks and fledglings of this ground-nesting species are taken by stoats, weasels and crows such as the European magpie, and