Gould undertook an ornithological tour of Scandinavia in 1856, in preparation for the work, taking with him the artist Henry Wolf who drew 57 of the plates from Gould's preparatory sketches. According to The University of Glasgow Gould's skill was in rapidly producing rough sketches from nature (a majority of the sketches were drawn from newly killed specimens) capturing the distinctiveness of each species. Gould then oversaw the process whereby his artists worked his sketches up into the finished drawings, which were made into coloured lithographs by engraver William Hart.