The Española cactus finch (''Geospiza conirostris''), is a species of

bird Birds are a group of warm-blooded vertebrates constituting the class Aves (), characterised by feathers, toothless beaked jaws, the laying of hard-shelled eggs, a high metabolic rate, a four-chambered heart, and a strong yet lightweig ...

in the

tanager The tanagers (singular ) comprise the bird family Thraupidae, in the order Passeriformes. The family has a Neotropical distribution and is the second-largest family of birds. It represents about 4% of all avian species and 12% of the Neotropica ...

family

Thraupidae The tanagers (singular ) comprise the bird family Thraupidae, in the order Passeriformes. The family has a Neotropical distribution and is the second-largest family of birds. It represents about 4% of all avian species and 12% of the Neotropica ...

. It is one of

Darwin's finches Darwin's finches (also known as the Galápagos finches) are a group of about 18 species of passerine birds. They are well known for their remarkable diversity in beak form and function. They are often classified as the subfamily Geospizinae or t ...

, and is

endemic Endemism is the state of a species being found in a single defined geographic location, such as an island, state, nation, country or other defined zone; organisms that are indigenous to a place are not endemic to it if they are also found else ...

to the Galápagos islands, where it is restricted to Española, Genovesa, and the Darwin and Wolf Islands. This rather dark bird resembles the smaller and finer-beaked common cactus finch, but the two species do not co-inhabit any island. Its natural

habitat In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...

is dry shrubland and it is commonly seen on the ground. Its main food source is the cactus '' Opuntia''.

Taxonomy

The Española cactus finch is one of

, a group of closely related birds that

evolved Evolution is change in the heritable characteristics of biological populations over successive generations. These characteristics are the expressions of genes, which are passed on from parent to offspring during reproduction. Variation ...

on the Galápagos Islands. The group is related to the ''

Tiaris The yellow-faced grassquit (''Tiaris olivaceus'') is a passerine bird in the tanager family Thraupidae and is the only member of the genus ''Tiaris''. It is native to the Central America, South America, and the Caribbean. Taxonomy In 1760 the F ...

'' grassquits, which are found in South America and the Caribbean. An ancestral relative of those grassquits arrived on the Galápagos Islands some 2–3 million years ago, and the Española cactus finch is one of the species that evolved from that ancestor.Grant & Grant (2008), p. 25. From a study done in 2015, the Española cactus finch (''G. conirostris'') of Española was found to be a sister to the

large ground finch The large ground finch (''Geospiza magnirostris'') is a species of bird. One of Darwin's finches, it is now placed in the family Thraupidae and was formerly in the Emberizidae. It is endemic to the Galapagos Islands, and is found in the arid zone ...

, not to the

Genovesa cactus finch The Genovesa cactus finch (''Geospiza propinqua'') is a species of bird in the tanager family Thraupidae. It is one of Darwin's finches, and is endemic to the Galápagos islands, Ecuador, where it is restricted to Genovesa Island. Its natural ha ...

. The

International Ornithologists' Union The International Ornithologists' Union, formerly known as the International Ornithological Committee, is a group of about 200 international ornithologists, and is responsible for the International Ornithological Congress and other international ...

has changed the taxonomy based on the study. Other taxonomic authorities have kept the large cactus finch and the Genovesa cactus finch

conspecific Biological specificity is the tendency of a characteristic such as a behavior or a biochemical variation to occur in a particular species. Biochemist Linus Pauling stated that "Biological specificity is the set of characteristics of living organis ...

Genetic speciation

The Española cactus finch (G. conirostris) first arrived in

Daphne Major Daphne Major is a volcanic island just north of Santa Cruz Island and just west of the Baltra Airport in the Archipelago of Colón, commonly known as the Galápagos Islands. It consists of a tuff crater, devoid of trees, whose rim rises above the ...

in 1981, when it was observed to be a newcomer by

Peter and Rosemary Grant Peter Raymond Grant (born October 26, 1936) and Barbara Rosemary Grant (born October 8, 1936) are a British married couple who are evolutionary biologists at Princeton University. Each currently holds the position of emeritus professor. The ...

. This has enabled scientists to trace changes in its genome: it originally interbred with local finches ('' G. fortis'') but has ceased to do so in later generations. The new descendants have become a distinct species. It is the first example of speciation to be directly observed by scientists in the field. Subsequent genetic research suggests that genes for beak shape (ALX1) and beak size (HMGA2) may be crucial in separating the hybridized species from local finches. Genes relating to the finches' song may also be involved.

Description

The Española cactus finch is among the largest of the Darwin's finches, measuring in length. The male is black, with white-tipped undertail coverts. Female and immature birds range in color from dull gray to matte black, and frequently show white edges to the feathers of their underparts. File:Geospiza conirostris -Espanola, Galapagos, Ecuador-29Sept2010.jpg, Female on Española File:Geospiza conirostris -Espanola Island, Galapagos Islands, Ecuador-8.jpg, Male on Española

References

Cited works

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External links

Princeton Study Finds That New Species Can Develop in as Little as 2 Generations
On: SciTechDaily. November 24, 2017 {{Taxonbar, from=Q843364

Española cactus finch The Española cactus finch (''Geospiza conirostris''), is a species of bird in the tanager family Thraupidae. It is one of Darwin's finches, and is Endemism, endemic to the Galápagos islands, where it is restricted to Española, Genovesa, and th ...

Endemic birds of the Galápagos Islands

Taxa named by Robert Ridgway Taxonomy articles created by Polbot