During our walk in the morning we had a wonderful opportunity to have a close encounter with the large cactus finch (Geospiza cornirostris). This finch is one of the four species of finches that occur on Genovesa Island. Outside Genovesa Island this species of finch is only found on another three islands, Española and the remote Darwin and Wolf. We were really fortunate to observe it probing the "prickly pear cactus" flowers (Opuntia helleri). The finch was very active hopping from one side to the other, giving a hard time to the people, including me, who were trying to take a picture of it. After some minutes and with a great deal of patience, we were finally rewarded. The finch stayed briefly quiet for some seconds "modeling" for us.
The large cactus finch is one of the world-famous thirteen species of Darwin finches that live in the archipelago. Darwin finches are living proof of evolution. These highly specialized birds have developed different types of beaks according to the sorts of food they feed on. The range of beak shapes from that of the large ground finch to that of the warbler finch is phenomenal, considering their relatively recent evolution from a common ancestor. The large cactus finch shown today has an unmistakable and characteristic flattened beak on the sides, in addition, its lower mandible is flatter and less convex in profile than that other ground finches.
In the picture of today we can appreciate clearly a large cactus finch with some grains of pollen attached to its beak and plumage. Finches are active pollinators of cacti on Genovesa, helping these plants to survive and getting dispersed all over the island.
