Darwin’s Finches

In the beginning…

Who knew the humble Finch would one day hold the key to an understanding of nature so profound as to shake the very foundation of the way we observe the world? It did, and it was the calling of one individual, Charles Darwin, to expound upon, refine and clarify the principle of variation among all species on earth.

It is our hope that you will view your garden birds with greater beauty than before, with a more profound understanding, by seeing them in context, and knowing they arrived here from a long established, uninterrupted lineage that dates far back to the very early days of life on earth.

But first, what of the man who made this discovery? It all dates back to the 19th century.

Our distinguished naturalist

Charles Darwin, born in 1809 at The Mount in Shrewsbury, is our most iconic naturalist. Famed globally for his book, The Origin of Species (1859), he was the first person to explain in considerable detail and clarity a theory for explaining the vast diversity of species on earth: The Theory of Natural Selection.

What led him to this conclusion was many years of systematic investigations, an obsessive interest in biology and, of course, a very significant journey around the world aboard HMS Beagle.

It was here, in 1831, that Darwin received his invitation to travel the world with the aristocratic Captain Robert FitzRoy. At first it was almost cancelled by Darwin’s father, Robert, but after receiving support and encouragement from his uncle, Josiah Wedgewood, Robert agreed with the journey, and decided to fund it.

And this is where history was made; for the next five years, Darwin grasped fully the opportunity and freedom to study the geology, flora and fauna of the South American coast, which was under survey by HMS Beagle.

A young Darwin, circa 1830

The Galápagos Islands

On September 15th 1835, HMS Beagle arrived at Galápagos to observe and study the biology of several of the islands, although at the time Darwin was more interested in Geology – in fact, so impressed by the volcanic craters of the Galápagos, Darwin referred to the archipelago as “that land of craters.”

It was around this time that Darwin began to notice that a number of “Mockingbirds” (thirteen altogether), deriving from different islands, differed from each other, although he made the assumption that they were unrelated. It was only later when a number of these specimens were returned to England for further investigation that these “Mockingbirds” were in fact found to be a species of passerine birds unique to the Galápagos Islands. Although they came to be known as Darwin’s Finches, they are not closely related to the group of true finches we know so well in our gardens (*Fringillidae: vCarduellis, Spinus, Chloris etc).

In no world but a fallen one could such lands exist,” Melville, The Encantadas

Enlisting the help of the illustrious ornithologist, John Gould, Darwin handed over the birds for examination and, after careful analysis, Gould came to the conclusion that these Finches formed a new species group specific to the Galápagos Islands (Geospiza); so ground breaking was this news that it even made the newspapers.

This was a pivotal moment, an intellectual light-bulb, if you will, in Darwin’s progress of a refined theory as to how species could, in his terms, “undermine stability”, disrupting the common Victorian understanding that species do not change, but remain stable and unchanging (i.e. do not transmute).

Beak variation among Galápagos Finches

And it all boiled down to beak variation; as Darwin wrote in The Voyage of the Beagle, “the most curious fact is the perfect gradation in the size of the beaks in the different species of Geospiza, from one as large as the Hawfinch to that of a Chaffinch.” It was a simple intellectual step for Darwin, and he asked if these thirteen birds evolved from one single ancestor. The evidence most certainly pointed to this fact, that they did indeed share a single common ancestor, a ground-feeding, seed-eating Finch. All thirteen present Finches had subsequently adapted their beaks to suit the conditions of each different island: it turns out that specific Galápagos finches have different dietary requirements, some preferring seeds and insects, while others prefer leaves and flowers – their individual beaks suitably shaped for consuming these different foods.

And this, of course, was a breakthrough in scientific understanding; an intellectual leap, one could argue, as profound as Newton’s Universal Law of Gravitation, or Michael Faraday’s research into electricity. It has reshaped the way many of us view life on earth, and it all came from a group of humble Finches.

We urge you to take a look outside and ponder the significance, enjoy the thought that many of the garden birds you observe have derived from a long and complex evolutionary line of common ancestors, dating back to the dinosaurs, and more, into the furthest depths of the past.