Cactus Finch Feeding

This is a Cactus Finch (Geospiza scandens), feeding on a cactus fruit on Santa Fe Island in the Galapagos. The island has many large, even tree-sized Opuntia cactuses (a variety of prickly pear)--some over 40 feet or 12 meters in height. As a consequence, there are many cactus finches, with distinctly pointed bills that have evolved to permit feeding on the fruit or insects in the flowers,in the manner seen here.

There are 13 species of finches on the Galapagos Islands, which ornithologists believed have evolved from a single original ancestor which reached the islands many millennia ago. The main differential feature is the beak, which has developed in each species according to its main food and foraging habits. Darwin saw the Galapagos finches as a key supporting element in his theory of evolution, and they have come to be called "Darwin's finches."

The other finch in this series is the small tree finch.

(Backblipped--for an overview, see 20 July)