Four species of mockingbird can be found in Galapagos, none of which occur anywhere else on Earth.
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During the voyage of HMS Beagle, Darwin studied hundreds of specimens including a good number of mockingbirds, or mocking-thrushes as he called them. It was these specimens more than any other that led him to develop his theory of evolution by natural selection.
Darwin noted that mockingbirds differed slightly between islands in their size, beak shape and markings but still closely resembled the mockingbirds that he had collected from mainland South America. This, along with other observations such as the differing shell shapes of giant tortoises, made him question the long-held belief that all species had been created in their current form, and it was these observations that led him to formulate his revolutionary theory.
Observations made by Charles Darwin during his visit to Galapagos in 1835 have given the Archipelago a special place in history and in the development of modern science.
Four species of mockingbird can be found in Galapagos, none of which occur anywhere else on Earth. Genetic analysis has shown that all have descended from a common ancestor, likely to be the original Galapagos settler, whose closest living relatives are the mockingbirds found in North America.
The Galapagos mockingbird (Mimus parvulus) is by far the most common of the four species within the Archipelago and can be readily spotted in the forests and shrublands of many of the larger islands. The other three species are the Española (M.macdonaldi), San Cristobal (M.melanotis) and Floreana mockingbirds (M.trifasciatus), named after the islands from which they originate. Sadly, all four species are listed on the IUCN Red List of Threatened Species, the most threatened being the Endangered Floreana mockingbird.
The Galapagos mockingbird is the most common mockingbird species found in the Archipelago.
Once common on Floreana, the Floreana mockingbird population is now restricted to two small satellite islands and may number less than 200 individuals. The principal threats to all of the mockingbird species are predation from introduced predators (namely rats and cats) and loss of their favoured nesting and food source, the prickly pear cactus (Opuntia spp.).
Fortunately, the Restoring Floreana project, which GCT has been helping to fund for more than two decades, is focused on reintroducing locally extinct species to the island by eradicating invasive species.
We are supporting a hugely ambitious project to restore Floreana to its former glory.
Originally named mock-birds in the 1640s, mockingbirds are so named due to an interesting behaviour carried out by some species whereby they mimic the calls of insects, amphibians and other bird species. None of Galapagos’ mockingbirds perform their namesake behaviour, but they do have a series of calls which they will use under different conditions.
Amazingly, marine iguanas appear to have learnt to recognise the alarm calls of mockingbirds and have been shown to act upon them. When a predator is spotted, iguanas will often go into a heightened state of alert when an alarm call is raised. This makes sense given that the two species share many of the same predators, such as the Galapagos hawk.
Whilst there are many examples in the natural world of one species reacting to the calls of another, such as meerkats reacting to fork-tailed drongo alarm calls in the Kalahari, this is the first time that it has been recorded in a non-vocalising species such as the marine iguana.
There seems to be a strange irony in the fact that the bird that played an integral part in Darwin’s theory of evolution has evolved to no longer show the behaviour that gave it its name. What is certain is that these bold and charming birds are always a pleasure to watch in Galapagos, and are just one more reason to conserve this wonderful Archipelago.
Discover the amazing diversity of wildlife in Galapagos is what makes the Archipelago so special.
