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
Eastern Canary Islands chiffchaff Eastern Canary Islands chiffchaff The eastern Canary Islands chiffchaff or Lanzarote Island chiffchaff ("Phylloscopus canariensis exsul") is an extinct subspecies of the Canary Islands chiffchaff endemic to the island of Lanzarote – and possibly also Fuerteventura – in the Canary Islands, Spain. The eastern Canary Islands chiffchaff was more chestnut-backed and shorter-winged than the western Canary Islands chiffchaff, "Phylloscopus canariensis canariensis". These birds were formerly considered subspecies of the common chiffchaff but separated (Clement & Helbig, 1998; Sangster "et al.", 2001) due to their morphological, bioacoustical, and mtDNA sequence differences (Helbig "et al.", 1996). Apparently this subspecies was already very