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
Handbook of the Birds of the World to Scientific Names in Ornithology'. A list of volumes of the "Handbook of the Birds of the World" produced to date is as follows: This volume was published in 1992. Unlike subsequent volumes, it does not have an introductory essay; instead, it has a 38-page overview by Eduardo de Juana of the biology of birds and a foreword welcoming the HBW project, by Christoph Imboden. Groups covered in this volume are as follows: This volume was published in 1994. It has a foreword by Walter J. Bock on the organization of information in HBW. Groups covered in this volume are