Gould’s work in identifying and cataloguing the bird specimens Darwin brought back from the Galápagos Islands was crucial in the formation of his theory of natural selection (Darwin hadn’t recognised new species, or that the species were specific to separate islands). Lear — a noted natural-history illustrator as well as humourist — was engaged to produce illustrations for him, but quit, upset that Gould took all the credits and that he, Lear, was making nothing from it. Gould’s wife Elizabeth, and Wolf, also worked for him as illustrators. He took Gilbert to Australia to collect for him, and met the explorer Sturt there.
Aged only sixteen, Ridgway went as naturalist on expedition with King. He also accompanied Muir and Curtis (among others) on a well-funded exploration of the Alaskan coast. Baird invited him to be the Smithsonian’s curator of ornithology, and he collaborated with Baird and Bremer on a monumental study of North American birds.