Ernst Mayr—Intellectual leader of ornithology

Ernst Mayr (1904–), naturalist and ornithologist since his early youth, is one of the ‘architects’ of the synthetic theory of evolution of the 1940s. His main contribution was the analysis of the origin of species, i.e. the causes of biodiversity. The historical roots of these ideas reach far back to the early 1920s, when the 19-year-old student suggested to his mentor, Dr. Erwin Stresemann (Berlin), the development for birds of a “theory of geographical variation and of the species.” During the 1930s, Mayr himself assembled data for a comprehensive analysis of geographical variation and speciation in birds, when he studied the rich collections of the Whitney South Sea Expedition from the islands in the Pacific Ocean. He described from this and other regions 27 new species and 445 new subspecies of birds, more than any other living ornithologist. He established the basic principles of island biogeography, discussed critically the former existence of landbridges and emphasized that, in zoogeographical studies, “instead of fixed regions, it is necessary to think of fluid faunas.” His theoretical framework included active jump dispersal of birds and other animals as well as various types of vicariance processes which had an effect on faunal differentiation. Although Mayr was not the originator of the biological species concept, he demonstrated its validity more convincingly than anyone else before and proposed a superior and concise definition of the biospecies which everybody adopted. He also initiated with various studies a period of renewed interest in the macrosystematics of birds.