When it comes to teaching young children about Darwin, the NSF’s $2 million Evolution Readiness Project recommends resources that give him no end of praise. One of their recommended resources, the book Life on Earth: The Story of Evolution, calls “the theory of evolution … one of the great accomplishments of science.” One of the prime examples of evolution in the book is the classic Galápagos finch beak story.

Darwin, we are told, visited the Galápagos islands and “found a [sic] unusual group of finches” which “gave Darwin important clues about the way evolution works.” Supposedly Darwin “noticed that on each islands the birds’ beaks were shaped differently” and “Darwin believed that small changes in the birds over many generations had resulted in fourteen different species, each with a beak adapted to a particular diet.”

While this is an accurate description of what scientists believe about the finches today, most of this was unknown to Darwin and his contemporaries. In fact, Darwin didn’t come up with these ideas about finches. Far from identifying 14 species of finches, Harvard Darwin historian Frank J. Sulloway explains how badly Darwin botched his analysis of these birds:

Just how greatly Darwin was misled by certain of the Galápagos finches is poignantly illustrated by his misclassification of the warbler finch as a “wren,” or warbler. As for the remarkable woodpecker finch, thought by many to have stimulated Darwin’s greatest evolutionary curiosity, this species was not even collected by Darwin; and its unusual tool-using behavior was not reported until 1919. Darwin collected, in fact, only nine of the present thirteen species of “Darwin’s finches.” Of these, he properly identified as finches only six species – less than half the present total – placing them in two separate groups, large- and small-beaked Fringillidae.

(Frank J. Sulloway, “Darwin and His Finches: The Evolution of a Legend,” Journal of the History of Biology, Vol. 15 (1):1-53 (Spring, 1982) (internal citations omitted).)

And what about the claim that Darwin studied differences in finch beaks to determine that they evolved their differences to become “adapted to a particular diet?” Here, Sulloway says:

To establish a presumption that his Galápagos finches had indeed evolved such divergent forms through adaptive radiation, it was first necessary to show that the different shapes of their beaks were in some way effective in reducing competition. But Darwin lacked precisely this information. According to his own testimony, the several species of Geospiza were “indistinguishable from each other in their habits,” feeding together on the ground in large irregular flocks. These observations were not only incomplete but also incorrect. … Darwin failed to correlate feeding habits in the Galápagos finches with their diverse beaks, and partly for this reason most subsequent ornithologists thought that there was no relationship.

(Frank J. Sulloway, “Darwin and His Finches: The Evolution of a Legend,” Journal of the History of Biology, Vol. 15 (1):1-53 (Spring, 1982) (internal citations omitted).)

Today, Darwin’s finches are a mainstay line of evidence used to buttress Darwinian evolution–Life on Earth uses them as a centerpiece example.

But if they’re such great evidence for evolution, why did Darwin completely leave them out of Origin of Species? The answer, as Sulloway points out, is that in Darwin’s time, no one had yet done the painstaking research to discover all the various species, study their feeding habits, and understand the evolutionary significance of the of small, often minute differences in beak size.

It seems that the book is confusing Darwin with Peter and Rosemary Grant and many other finch researchers who came in the decades and century after Darwin, because they are the ones who identified all the finch species and studied the different shapes of their beaks. But little details like that don’t matter. Darwin gets all the glory.

And even if the finch legend was true, what would it show? Millions of years of evolution, and the finches are still finches capable of interbreeding. They’re nearly identical, apart from variation in diet and small-scale size changes in beaks. This data cannot be extrapolated to bolster the grander macroevolutionary claims of Darwinian evolution.