It is widely believed that Darwin’s Galápagos finches inspired his theory of natural selection. Nothing could be further from the truth.  Darwin’s failure to label his Galápagos finch specimens by island, and his lack of useful behavioral observations about the differing diets of these birds, limited his ability to argue that their diverse beaks had evolved by natural selection to fill different ecological niches. For these reasons, these birds are not even mentioned in the Origin of Species. As is well established by historians of science, and as is further supported by Darwin’s own testimony, his revolutionary theory of natural selection was inspired by his reading of Thomas Robert Malthus’s book On Population in September 1838, three years after Darwin’s historic visit to the Galápagos Islands and two years after his return to England on the Beagle.  What Darwin’s Galápagos birds, including the famous finches, helped him to understand is that species often grade insensibly into one another and that varieties, as he later argued in the Origin of Species, are “incipient species.” It was the largely underappreciated existence of this variability among species in nature that allowed Darwin to grasp how natural selection might give rise to new species. Inspired in part by David Lack’s (1947) influential book Darwin’s Finches, the pervasive myth associated with these iconic birds is a classic instance of how important scientific discoveries often become telescoped around a dramatic moment of eureka-like insight, obscuring what typically proves to be a more protracted and conceptually multifaceted processes of scientific innovation.

It is sometimes said that Darwin was converted to the theory of evolution by the striking evidence provided by his famous Galápagos finches, and, in this connection, that his historic visit to the Galápagos Islands had an immediate impact on his evolutionary thinking.  Such was not the case.  During his five-week visit to these islands in September and October 1835, Darwin was still under the spell of creationist thinking, so much so that he failed to label most of his Galápagos birds by island—information that was of vital importance for establishing that these species had arisen by geographic isolation on the different islands of the Galápagos group.  Moreover, at the time Darwin collected the famous finches that are now named after him, he was misled by their remarkable beak diversity into thinking they were members of different avian families rather than being closely related descendants of a common ancestor. It was not until after Darwin’s return to England, and more particularly during Darwin’s fateful meeting with distinguished ornithologist John Gould in March of 1837, that Darwin finally became convinced that different species of birds indeed inhabited the different islands of the Galápagos group.  In addition, Gould’s astute correction of Darwin’s provisional voyage taxonomic assessments of the Galápagos finches allowed Darwin to grasp that these birds were members of a single avian subfamily. Inspired by this new information, Darwin realized that evolution could account for it, and he now generalized these conclusions to other aspects of his Beagle voyage collections.