|Geospiza magnirostris - Picture: Wikipedia|
Charles Darwin came to the islands and collected what is now called Darwin's finches, although Darwin himself did not think to give them this name. There are 14 Darwin's finches all in all; 13 in the Galapagos Islands and 1 in the Coco's Island which is about 400 miles north of the Galapagos all of them belonging to the Passerine group.
There is evidence that evolution took place on the island particularly involving Galapagos finches. Finches that have the same ability as woodpeckers because they are able to peck on woods are found here; as well as vampire finches, which suck the blood of other birds. Genetic specialists have suggested that all 13 of Darwin's species have evolved from a flock of giving or take 30 birds arriving about a million years ago.
Darwin's finches / Galapagos finches are 10-20 centimeters in size and the most important differences among each one of them, is the shape and size of their beaks. Each shape and size of beak has evolved and adapted to different food sources. Large-beaked finches like bigger seeds or nuts, while smaller-beaked finches prefer smaller seeds. Middle-beaked finches can also be found on the island.
Apart from seeds, these finches differ in other food choices. Some eat insects, leaves, and some remove turtle ticks. The vampire finch, for instance, feeds on the blood of seabirds. The woodpecker finch, on the other hand, is one among the few birds in the world that uses various "tools" like twigs or cactus spine when feeding. They particularly use these tools to pry larvae and other insects from beneath barks of trees or cacti.
The ground finches have bills that are more adapted to crushing seeds. The Vampire Finch, which is found in Wolf Island, is a type of ground finch and its behavior likely evolved from eating insect parasites from its own plumage.
Tree finches are another type of Galapagos finches. They mainly feed on insects and differ from ground finches by the sharpness of their bill which is better suited in grasping insects. Cactus finches enjoy eating small insects in the flowers of the cactus plants.
The 13 species of finches in the Galapagos are of the genus Geospiza and are likely to have descended from a South American species, either the St.Lucia black finch or the blue-black grassquit. When Darwin was collecting these birds, he did not immediately realize that these birds were all different species of finches. Soon after he suspected that there was more than meets the eye, he began his work on "Transmutation of the Species".
There's no doubt that these species are particularly popular for their significance in the development of the theory of evolution and are popular pet choices as well.
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Article Source: EzineArticles