Vampire Finch
Encyclopedia
The Vampire Finch is a small bird
native to the Galápagos Islands
. It is a very distinct subspecies
of the Sharp-beaked Ground Finch (Geospiza difficilis) endemic to Wolf
and Darwin Island
s.
The vampire finch is sexually dimorphic
as typical for its genus
, with the males being primarily black and the females grey with brown streaks. It has the largest and most pointed beak of all G. difficilis subspecies, and overall looks like a miniature Common Cactus-Finch
rather than, as the other subspecies do, a large Small Ground-Finch
with a straight bill. It has a lilting song on Wolf, a buzzing song on Darwin, and whistling calls on both islands; only on Wolf, a drawn-out, buzzing call is also uttered.
This bird is most famous for its unusual diet. The Vampire Finch occasionally feeds
by drinking the blood of other birds, chiefly the Nazca
and Blue-footed Boobies
, pecking at their skin with their sharp beaks until blood is drawn. Curiously, the boobies do not offer much resistance against this. It has been theorized that this behavior evolved from the pecking behavior that the finch used to clean parasites from the plumage of the booby. The finches also feed on eggs, stealing them just after they are laid and rolling them (by pushing with their legs and using their beak as a pivot) into rocks until they break.
More conventionally for birds, but still unusual among Geospiza, they also take nectar from Galápagos prickly pear (Opuntia echios var. gigantea) flowers at least on Wolf (Schluter & Grant 1984). The reasons for these peculiar feeding habits are the lack of freshwater
on these birds' home islands. Nonetheless, the mainstay of their diet is made up from seeds and invertebrates as in their congeners.
The vampire finch is endangered, being a small-island endemic. The Galápagos finch species collectively form a showcase example of Charles Darwin
's theory of natural selection
. The 14 or 15 species of Galapagos finches are often called "Darwin's Finches
". They are used as an example of how the descendants of one ancestor can evolve into several species as they adapt to different conditions.
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...
native to the Galápagos Islands
Galápagos Islands
The Galápagos Islands are an archipelago of volcanic islands distributed around the equator in the Pacific Ocean, west of continental Ecuador, of which they are a part.The Galápagos Islands and its surrounding waters form an Ecuadorian province, a national park, and a...
. It is a very distinct subspecies
Subspecies
Subspecies in biological classification, is either a taxonomic rank subordinate to species, ora taxonomic unit in that rank . A subspecies cannot be recognized in isolation: a species will either be recognized as having no subspecies at all or two or more, never just one...
of the Sharp-beaked Ground Finch (Geospiza difficilis) endemic to Wolf
Wolf Island
Wolf Island or Wenman Island is a small island in the Galapagos Islands and was named after the German geologist Theodor Wolf, who also has the volcano Wolf on Isabela Island named after him...
and Darwin Island
Darwin Island
Darwin Island is named in honor of Charles Darwin, and is among the smallest in the Galapagos Archipelago with an area of just one square kilometer. With no dry landing sites, Darwin Island's main attractions are found in the Pacific Ocean, which is teeming with a spectacular variety of marine life...
s.
The vampire finch is sexually dimorphic
Sexual dimorphism
Sexual dimorphism is a phenotypic difference between males and females of the same species. Examples of such differences include differences in morphology, ornamentation, and behavior.-Examples:-Ornamentation / coloration:...
as typical for its genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
, with the males being primarily black and the females grey with brown streaks. It has the largest and most pointed beak of all G. difficilis subspecies, and overall looks like a miniature Common Cactus-Finch
Common Cactus-finch
The Common Cactus Finch or Small Cactus Finch is a species of bird in the Darwin's finch group of the tanager family Thraupidae. It is endemic to the Galapagos Islands, where it is found on most islands, with the notable exception of Fernandina, Española, Genovesa, Darwin and Wolf...
rather than, as the other subspecies do, a large Small Ground-Finch
Small Ground-finch
The Small Ground Finch is a species of bird in the Darwin's finch group of the tanager family Thraupidae.It is endemic to the Galapagos Islands, and is common and widespread in shrubland, woodland and other habitats on most islands in the archipelago...
with a straight bill. It has a lilting song on Wolf, a buzzing song on Darwin, and whistling calls on both islands; only on Wolf, a drawn-out, buzzing call is also uttered.
This bird is most famous for its unusual diet. The Vampire Finch occasionally feeds
by drinking the blood of other birds, chiefly the Nazca
Nazca Booby
The Nazca Booby, Sula granti, is a booby which is found in the eastern Pacific Ocean, namely on the Galápagos Islands where it can be seen by eco-tourists, and on Clipperton Island...
and Blue-footed Boobies
Blue-footed Booby
The Blue-footed Booby is a bird in the Sulidae family which comprises ten species of long-winged seabirds. The natural breeding habitat of the Blue-footed Booby is tropical and subtropical islands off the Pacific Ocean, most famously, the Galápagos Islands, Ecuador.- Etymology :The name booby...
, pecking at their skin with their sharp beaks until blood is drawn. Curiously, the boobies do not offer much resistance against this. It has been theorized that this behavior evolved from the pecking behavior that the finch used to clean parasites from the plumage of the booby. The finches also feed on eggs, stealing them just after they are laid and rolling them (by pushing with their legs and using their beak as a pivot) into rocks until they break.
More conventionally for birds, but still unusual among Geospiza, they also take nectar from Galápagos prickly pear (Opuntia echios var. gigantea) flowers at least on Wolf (Schluter & Grant 1984). The reasons for these peculiar feeding habits are the lack of freshwater
Freshwater
Fresh water is naturally occurring water on the Earth's surface in ice sheets, ice caps, glaciers, bogs, ponds, lakes, rivers and streams, and underground as groundwater in aquifers and underground streams. Fresh water is generally characterized by having low concentrations of dissolved salts and...
on these birds' home islands. Nonetheless, the mainstay of their diet is made up from seeds and invertebrates as in their congeners.
The vampire finch is endangered, being a small-island endemic. The Galápagos finch species collectively form a showcase example of Charles Darwin
Charles Darwin
Charles Robert Darwin FRS was an English naturalist. He established that all species of life have descended over time from common ancestry, and proposed the scientific theory that this branching pattern of evolution resulted from a process that he called natural selection.He published his theory...
's theory of natural selection
Natural selection
Natural selection is the nonrandom process by which biologic traits become either more or less common in a population as a function of differential reproduction of their bearers. It is a key mechanism of evolution....
. The 14 or 15 species of Galapagos finches are often called "Darwin's Finches
Darwin's finches
Darwin's finches are a group of 14 or 15 species of passerine birds. It is still not clear which bird family they belong to, but they are not related to the true finches. They were first collected by Charles Darwin on the Galápagos Islands during the second voyage of the Beagle...
". They are used as an example of how the descendants of one ancestor can evolve into several species as they adapt to different conditions.
External links
- CentralPets.com: Vampire Finch. Retrieved 2006-DEC-19.