Eurasian wren (Nannus troglodytes) - Goldcrest (Regulus regulus) illustrated by the von Wright brothers. Digitally enhanced… Free Image from public domain license 
European roller (CORACIAS GARRULUS) illustrated by the von Wright brothers. Digitally enhanced from our own 1929 folio… Free Image from public domain license 
Great tit on paulownia branch (1925 - 1936) by Ohara Koson (1877-1945). Original from The Rijksmuseum. Digitally enhanced by… Free Image from public domain license