
There are four species of bird named Chiffchaff: ...
Found on
http://en.wikipedia.org/wiki/Chiffchaff

(Phylloscopus collybita), warbler (family Sylviidae, order Passeriformes) of western Eurasia, named for its song. This greenish brown bird, 11 cm ... [1 related articles]
Found on
http://www.britannica.com/eb/a-z/c/69

The chiffchaff is a small song bird. It visits England in the summer.
Found on
http://www.probertencyclopaedia.com/browse/BC.HTM

Small songbird
Phylloscopus collybita of the warbler family, Muscicapidae, order Passeriformes. It is found in woodlands and thickets in Europe and northern Asia during the summer, migrating south for winter. About 11 cm/4.3 in long, olive above, greyish below, with yellow-white nether parts, an eyestripe, and usually dar...
Found on
https://www.encyclo.co.uk/local/21221

a common, greenish Old World warbler, Phylloscopus collybita.
Found on
https://www.infoplease.com/dictionary/chiffchaff
No exact match found.