David Lambert Lack FRS, (16 July 1910 – 12 March 1973) was a British evolutionary biologist who made contributions to ornithology, ecology and ethology. His 1947 book, Darwin's Finches, on the finches of the Galapagos Islands was a landmark work. He developed Lack's principle.His pioneering life-history studies of the living bird helped to make ornithology respectable as a serious science. He became Director of the Edward Grey Institute of Field Ornithology at Oxford University.