Avian Expert Articles

Darwin’s Finches Continue to Evolve

By Peter Wilton (Large ground finchUploaded by Magnus Manske) [CC BY 2.0], via Wikimedia Commons
Charles Darwin is significant in our history for his studies and subsequent theory on the processes of evolution. As a result of this long and detailed work, which was eventually distilled within the texts of The Origin of The Species, his name became forever tied to any earnest discussion involving evolutionary theories of any kind. During his travels and studies, he spent some time in the Galápagos Islands. It was this visit to the Islands that helped to more fully shape his thoughts on species and the stability of species. On the Islands, Darwin, although not an ornithologist, collected finches that he soon discovered to be uniquely separated from finches found elsewhere.

The finches, now called Darwin’s Finches, are a collection of 13 species of birds that were considered vastly different in makeup from the finches in other parts of the world, even among themselves. This made the finches on the Galápagos Islands incredibly unique in appearance. After close evaluation by a well-respected ornithologist of the time, John Gould, the finches were determined to be separate species rather than varieties of the other finches of the world. Some of the differences included variable beak sizes, color, plumage, tail sizes, and behavior patterns. As a result of these studies, Darwin’s Finches became well known as representative of the divergence of species. Their existence helped Darwin advance his studies of evolution by natural selection.

New Species of Finch

Back in 1981, a non-native male cactus finch likely from Isla Española, a small Galápagos island located some 60 miles south, arrived on the northwestern island of Daphne Major, and mated with two native female ground finches. New variations of the divergent species of finches were hatched. Since that time, approximately 30 birds of that “new” species of finch are now native to the island of Daphne Major. This process of evolution is called speciation, and it’s going on right before the eyes of surprised scientists who actively monitor the birds of Galápagos Islands.

The new species of finch is currently called Big Bird by the scientists that are following this remarkable and unlikely event. Their successful existence has already begun to challenge and change what is known about how birds evolve. What was once thought to be a constructive result of necessary mutation effects over millennia can now also be realized as a fast route of evolution via a process called hybridization. This occurs by the introduction of two unique species in a successful mating and hatching process.

This hybridization has created distinct — and unique — changes in the offspring of the two finch species that resulted in a different beak shape, a bigger overall size, and even a new vocal pitch that clearly separates its birdsong from that of its parents. The new finches mated with each other, which helped to account for proliferation and purity of the thirty in existence today on the island of Daphne Major.

This newly evolving species could eventually mate with other species of finches on the island to create even more unique species, although such an occurrence is unlikely. But if it does, the Darwin evolutionary theory by natural selection is not only getting a new and important study, but is a rare chance to watch and be amazed at how nature works. And science was gifted with a fast track view of this concept within a single lifetime.

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