The colour of birds: Hans Duncker, pioneer bird geneticistDie Farbe der Vögel: Hans Duncker, ein Pionier der Vogelgenetik

Hans Duncker (1881–1961) is among the first avian geneticists, but remains poorly known. He trained as a biologist, completing his PhD at the University of Göttingen in 1905 and then became a high-school teacher in Bremen where he remained for the rest of his life. In 1921 he met Karl Reich (1885–1970) who was the first person to make recordings of bird song and was well-known for creating a strain of canaries that sang Nightingale (Luscinia megarhynchos) songs. Duncker provided a novel Darwinian/Mendelian explanation for how Reich's canaries acquired their songs. In the early 1920s, a time during which the field of genetics was rapidly developing in the USA and Britain, but not Germany, Duncker and Reich conducted large-scale breeding experiments to establish the pattern of inheritance of variegation and other traits in canaries. In 1925 Duncker met Generalkonsul Carl Cremer (1858–1938), who provided the financial backing for a massive and comprehensive study of inheritance of colour patterns in Budgerigars (Melopsittacus undulates). At the same time Duncker also initiated a project to create a red canary by hybridising canaries with the Red Siskin (Carduelis cucullata). Duncker recognized that bird-keepers had much to offer professional scientists (and vice versa) and was keen to bridge the gap between them and to this end in 1927 began his own journal “Vogel ferner Lander”. His research on the genetics of the canary and budgerigar resulted in the publication of a large number of papers in ornithological journals and magazines and several books. Duncker was a eugenicist, and when the National Socialists came to power in 1933 he supported and promoted the notion of positive eugenics. He was later (in 1990) condemned for these activities and for having been a Nazi, but we show that Duncker joined the Party only reluctantly. After WWII Duncker restored and re-catalogued the bird collections at the Übersee-Museum in Bremen. We discuss the possible reasons why Duncker's research, much of it very innovative, has been largely ignored internationally.