Common chiffchaff point, appears to be used to advertise an established territory and contact the female, rather than as a paternity guard strategy. Beyond the core territory, there is a larger feeding range which is variable in size, but typically ten or more times the area of the breeding territory. It is believed that the female has a larger feeding range than the male. After breeding has finished, this species abandons its territory, and may join small flocks including other warblers prior to migration. The male common chiffchaff returns to its breeding territory two or three weeks before the female and immediately
Common chiffchaff criterion of the IUCN Red List (that is, declining more than 30 percent in ten years or three generations). For these reasons, the species is evaluated as "least concern". None of the major subspecies is under threat, but "exsul", as noted above, is probably extinct. There is a slow population increase of common chiffchaff in the Czech Republic. The range of at least "P. c. collybita" seems to be expanding, with northward advances in Scotland, Norway and Sweden and a large population increase in Denmark. Common chiffchaff The common chiffchaff ("Phylloscopus collybita"), or simply the chiffchaff, is a common and