- Order: Passeriformes
- Family: Thraupidae
Isla Genovesa, Galápagos, Ecuador; 21 May 2014 © Shawn Billerman
The Sharp-beaked Ground-Finch is an unusual and enigmatic species of Darwin’s Finch, and yes they do have a relatively long and pointed beak. There are three different populations, and perhaps they are better treated as separate species although this requires some more research. Perhaps the most commonly observed population by travelers is that of Genovesa Island where the Sharp-beaked is relatively small and small billed, in fact not all that different from Small Ground-Finch on other islands. Molecular data suggests that this population may in fact be more closely related or perhaps it is of hybrid origin with the Small-Medium pair of ground-finches. The most well known population of the Sharp-beak is the one found in the far northwest on Darwin and Wolf Islands; this is the “Vampire Finch.” This form of the Sharp-beaked Ground-Finch harvests blood from larger seabirds such as the Nazca Booby. The finch pecks at the base of larger flight feathers and opens a wound from which it licks the blood. These islands are resource poor and this is clearly an adaptation to obtain nourishment from the one common resource on the island, other birds! Less well known is a population of Sharp-beaks found in the highlands of Fernandina and Santiago islands, these are relatively large and use an entirely different habitat type than the other two populations. More research is needed on song and molecular data to untangle the relationships and history of the various populations of Sharp-beaked Ground-Finches.
. 2010. Sharp-beaked Ground-Finch (Geospiza difficilis), Neotropical Birds Online (T. S. Schulenberg, Editor). Ithaca: Cornell Lab of Ornithology; retrieved from Neotropical Birds Online: http://neotropical.birds.cornell.edu/portal/species/overview?p_p_spp=632236