1. The species investigated were: Hawfinch(Coccothraustes coccothraustes), Chaffinch(Fringilla coelebs), Linnet(Acanthis cannabina), Greenfinch(Carduelis chloris), Goldfinch(C. carduelis), Serin(Serinus serinus) and the Spotted Flycatcher(Muscicapa striata).