Fringilla montifringilla, Brambling

The Brambling is similar in size and shape to a common chaffinch. Breeding-plumaged male bramblings are very distinctive, with a black head, dark upperparts, orange breast and white belly. Females and younger birds are less distinct, and more similar in appearance to some chaffinches. In all plumages, however, bramblings differs from chaffinches in a number of features:
  The Brambling has a white rump whereas that of chaffinch is grey-green. The breast is orange, contrasting with a white belly on brambling, whereas on chaffinch the underparts of more uniformly coloured (pink or buff),  brambling's scapular feathers are orange, whereas chaffinch's are grey or grey-brown; the flanks are dark-spotted on brambling, plain on chaffinch;  bramblings lack the white outer tail feathers of chaffinch.

An additional difference for all plumages except breeding-plumaged males is the bill colour - yellow in brambling, dull pinkish in chaffinch (breeding-plumaged male bramblings have black bills, chaffinches in the corresponding plumage have grey bills).