Niels Kjærbølling (1806–71) was the founder of the Zoological Garden in Copenhagen and published in 1847–1851 the first complete account of the birds of Denmark, “Ornithologia Danica”, which had a marked influence on the study of Danish birds. This very early collection of drawings is probably influenced by Naumann's “Naturgeschichte der Vögel Deutschlands” of which the first volume appeared in 1820. However, Kjærbølling explicitly states that he has drawn the birds after nature and supplied with his own observations. The manuscript is highly important documenting the very early beginning of Kjærbølling's career as ornithologist.