Siberian chiffchaff Siberian chiffchaff Siberian chiffchaff ("Phylloscopus (collybita) tristis") is a leaf-warbler which is usually considered a subspecies of the common chiffchaff, but may be a species in its own right. Siberian chiffchaff breeds in Siberia east of the Pechora River and winters in the lower Himalayas. It is also regularly recorded in western Europe in winter, and it is likely that the numbers involved have been underestimated due to uncertainties over identification criteria, lack of good data and recording policies (Sweden and Finland only accept trapped birds). Because of their unfamiliar appearance, British records in the 1950s and 1960s were originally
Common chiffchaff the adults are hunted by birds of prey, particularly the sparrowhawk. Small birds are also at the mercy of the weather, particularly when migrating, but also on the breeding and wintering grounds. The common chiffchaff is occasionally a host of brood parasitic cuckoos, including the common and Horsfield's cuckoos, but it recognises and rejects non-mimetic eggs and is therefore only rarely successfully brood-parasitised. Like other passerine birds, the common chiffchaff can also acquire intestinal nematode parasites and external ticks. The main effect of humans on this species is indirect, through woodland clearance which affects the habitat, predation by cats, and