Visit Galápagos: Islands of Darwin’s Inception, Climate Portent

Visit Galápagos: Islands of Darwin’s Inception, Climate Portent

Baltra Island is the rather drab spot where most tourists first step on the Galápagos Islands, which played a key role in transforming 19th century science. Actually, the birds of the Galápagos Islands continue to surprise scientists. Galápagos Tours are continually popular among birders, scientists, photographers and historians of science.

Baltra Island: Doorway to Galápagos Science, Tourism

By Rex Graham

Not part of the Galápagos National Park, Baltra Island, which also know as South Seymour, is flat, arid and barren. The island has a small airport and a sparse grassland that is home to several species of ground finches, birds so inconspicuous that many of the 150,000 tourist per year who come here might not notice these avian icons of science.

The medium ground Finch (Geospiza fortis) (Gould, 1837) in the vertebrates collection at the Charles Darwin Foundation, is one of the 14 finch species Darwin studied. Males are black-colored, females are cream-colored. (Charles Darwin Foundation) topbirdingtours.com

The medium ground Finch (Geospiza fortis) (John Gould, 1837) in the vertebrates collection at the Charles Darwin Foundation, is one of the 14 finch species Darwin studied. Males are black-colored, females are cream-colored. (Charles Darwin Foundation)

Visit Galápagos, See Darwin’s Finches

Baltra island hosts an occasional Sea Lion, but the island lost all of its Galapagos Land Iguanas in the 1950s. The lizards were later reintroduced and now there are nearly 100 individuals. Baltra Island also is home to Noddies (a Tropical member of the tern family), Brown Pelicans and the Great Frigatebird. Millions of tourists have come to the Galápagos Islands through Baltra, drawn to the isolated islands’ historic role in Charles Darwin’s then radical theory in the mid-1800s about the evolution of species by natural selection.

British ornithologist John Gould was the first to discover that the Galapagos birds Darwin described as blackbirds, "gros-beaks," finches and Darwin’s Galápagos wren were 13 species of finches. (1860 photographer unknown, Gould’s drawings) topbirdingtours.cm

British ornithologist John Gould was the first to discover that the Galapagos birds Darwin described as blackbirds, “gros-beaks,” finches and Darwin’s Galápagos wren were 13 species of finches. (1860 photographer unknown, Gould’s drawings)

Darwin’s Later-Acquired Interest in Galápagos Finches

Visit Galápagos: Darwin first visited the islands when he was 26 years old on his first voyage aboard the HMS Beagle. On his second voyage to the Galápagos Islands, he described a group of collected birds as blackbirds, “gros-beaks,” finches and a Galápagos wren. In 1937, when Darwin Darwin deposited his bird and mammal specimens at the Geological Society of London, ornithologist John Gould identified Darwin’s group of Galápagos blackbirds, “gros-beaks,” finches and a Galápagos wren as actually being 13 related species of finches.

Darwin was surprised. He had not labeled the birds he collected by their Galápagos island of origin, however the HMS Beagle’s captain, Robert FitzRoy, had made those notations. Darwin’s conclusions made in 1839 on the island-specific speciation of the finches was a key breakthrough in his derivation of the theory of evolution by natural selection. Darwin concluded, as did his colleague Alfred Wallace, that the original finches to land on the islands had adapted in ways that better equipped them to acquire food in their new home. The evidence was in the finches’ beaks.

Darwin went on to observe similar patterns of inherited variations in many other animal species.

Princeton University evolutionary biologists Peter and Rosemary Grant have studied Galápagos Islands finches since 1976. (Princeton University)  topbirdingtours.com

Princeton University evolutionary biologists Peter and Rosemary Grant have studied Galápagos Islands finches since 1976. (Princeton University)

Modern Day Darwin Proteges

Literally, following in Darwin’s footsteps on the Galápagos, Princeton University evolutionary biologists Peter and Rosemary Grant studied the islands’ finch populations since 1976, including a high-rainfall period when large, hard seeds that large-billed birds ate were fewer. During the same time, smaller, softer seeds that small-billed birds ate became more numerous. The Grants reported that smaller average bill size, an inherited trait, were more prominent, giving an advantage to finch parents with smaller and smaller bills. When the wet period ended in 1987, larger seeds became more available, the trend toward smaller and smaller average bill size in the finches stopped.

The Itabaca channel between Baltra Island (right) and Santa Cruz Island (left) in the Galapagos Islands Archipelago. (David Adam Kess) birdsnews.com

The Itabaca channel between Baltra Island (right) and Santa Cruz Island (left) in the Galapagos Islands Archipelago. (David Adam Kess)

Visit Galápagos – History Not Yet Finished

The Grants surprising findings revealed that evolutionary change can occur at a rapid pace, such as during the multi-year weather shift caused by El Niño. The work of the Grants is especially important in the modern era as climate change is expected to result in sweeping, long-term changes in weather patterns worldwide. The dedicated efforts of the Grants, together with Darwin’s original observations on the Galápagos, have forever enshrined the island archipelago as enormously important in the history of science.