The ethology and life history of birds: the forgotten contributions of Oskar, Magdalena and Katharina Heinroth

Oskar Heinroth was a pioneering German ornithologist of the early-mid 20th century whose three major contributions to ornithology have been largely overlooked. First, he conducted a systematic comparative study of the avian social signals and other behaviours (in waterfowl, including hybrids) and was the first to recognise that their instinctive, ritualized displays could serve as taxonomic criteria. Konrad Lorenz later developed the idea and also gained most of the credit for it. Second, Heinroth, together with his first wife Magdalena, hand-reared about 1,000 individuals of 286 species of birds in their apartment over 28 years, documenting and photographing their development. The results, published in four substantial volumes (1924–1933) were well received, but the deteriorating financial and political situation in Germany before WWII, together with the lack of an English translation, meant that the project received less attention than it warranted. Third, Heinroth provided a framework for studying and understanding the behaviour of birds that included detailed observations throughout the animals’ life; making use of tame individuals; and comparisons between captive and wild individuals. The value of this approach to the study of behaviour is exemplified by the Heinroths’ results from rearing European Nightjars Caprimulgus europaeus in their apartment. We propose that these contributions as well as numerous other anecdotes and observations in Heinroth’s publications merit further examination.