Darwin's mockingbirds

'If there is the slightest foundation for these remarks, the zoology of archipelagoes will be well worth examining; for such facts would undermine the stability of species.'
Charles Darwin

This bird, collected by Darwin in the Galápagos Islands, is the very first Floreana mockingbird (Nesomimus trifasciatus) described by science.

Although finches are the most famous Galápagos residents to have drawn Darwin's attention, it was these mockingbirds that laid the foundation for his theory of evolution by natural selection, an idea that took him 20 years to publish.

When he first arrived in the Galápagos in 1835, Darwin collected a number of mockingbird specimens. On one island (Chatham Island, now San Cristóbal Island), he noticed a mockingbird similar to those he had seen in Chile. On another island (Charles Island, now Floreana Island), however, he found the mockingbirds to be quite different. He later found a third species on Isabela Island.

These finds were Darwin's first hint that species could indeed evolve over time, thus refuting the so-called 'stability of species' theory. He reasoned that a single species from the mainland could have colonised the archipelago and gradually evolved into different species on different islands.

Find out more about the birds collected aboard the HMS Beagle >
Explore other key objects related to the theory of evolution >