Cocornis agassizi = Pinaroloxias inornata, cocos finch

The Cocos finch or Cocos Island finch (''Pinaroloxias inornata'') is the only one of the

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 ...

not native to the

Galápagos Islands The Galápagos Islands (Spanish: , , ) are an archipelago of volcanic islands. They are distributed on each side of the equator in the Pacific Ocean, surrounding the centre of the Western Hemisphere, and are part of the Republic of Ecuador ...

, and the only member of the

genus Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...

''Pinaroloxias''. Sometimes classified in the family

Emberizidae The buntings are a group of Old World passerine birds forming the genus ''Emberiza'', the only genus in the family Emberizidae. The family contains 45 species. They are seed-eating birds with stubby, conical bills. Taxonomy The family Emberizid ...

, more recent studies have shown it to belongs 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. It 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 elsew ...

Cocos Island Cocos Island ( es, Isla del Coco) is an island in the Pacific Ocean administered by Costa Rica, approximately southwest of the Costa Rican mainland. It constitutes the 11th of the 13 districts of Puntarenas Canton of the Province of Puntarenas ...

, which is approximately south of

Costa Rica Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...

. It is a chunky 12 cm long finch, weighing around 12.5 g and with a black decurved pointed bill. The male is entirely black, while the female is a heavily streaked brown, with a paler underside. The young are similar but have yellow bills. The standard clutch is two brown-spotted white

eggs Humans and human ancestors have scavenged and eaten animal eggs for millions of years. Humans in Southeast Asia had domesticated chickens and harvested their eggs for food by 1,500 BCE. The most widely consumed eggs are those of fowl, especial ...

, which are hatched in a roughly spherical

nest A nest is a structure built for certain animals to hold eggs or young. Although nests are most closely associated with birds, members of all classes of vertebrates and some invertebrates construct nests. They may be composed of organic materia ...

built at the end of a tree branch.

Taxonomy

The Cocos finch was formally described in 1843 by the English ornithologist

John Gould John Gould (; 14 September 1804 – 3 February 1881) was an English ornithologist. He published a number of monographs on birds, illustrated by plates produced by his wife, Elizabeth Gould, and several other artists, including Edward Lear, ...

under the

binomial name In taxonomy, binomial nomenclature ("two-term naming system"), also called nomenclature ("two-name naming system") or binary nomenclature, is a formal system of naming species of living things by giving each a name composed of two parts, bot ...

''Cactornis inornatus''. The species was moved to a new genus ''Pinaroloxias'' by

Richard Bowdler Sharpe Richard Bowdler Sharpe (22 November 1847 – 25 December 1909) was an English zoologist and ornithologist who worked as curator of the bird collection at the British Museum of natural history. In the course of his career he published several mono ...

in 1885. The genus name combines the

Ancient Greek Ancient Greek includes the forms of the Greek language used in ancient Greece and the ancient world from around 1500 BC to 300 BC. It is often roughly divided into the following periods: Mycenaean Greek (), Dark Ages (), the Archaic peri ...

''pinaros'' meaning "dirty" or "squalid" with ''

Loxia The crossbill is a genus, ''Loxia'', of birds in the finch family (Fringillidae), with six species. These birds are characterised by the mandibles with crossed tips, which gives the group its English name. Adult males tend to be red or orange in ...

'', a genus introduced by

Carl Linnaeus Carl Linnaeus (; 23 May 1707 – 10 January 1778), also known after his ennoblement in 1761 as Carl von Linné Blunt (2004), p. 171. (), was a Swedish botanist, zoologist, taxonomist, and physician who formalised binomial nomenclature, the ...

in 1758 for the crossbills. The specific epithet ''inornata '' is

Latin Latin (, or , ) is a classical language belonging to the Italic branch of the Indo-European languages. Latin was originally a dialect spoken in the lower Tiber area (then known as Latium) around present-day Rome, but through the power of the ...

for "plain" or "unadorned". The Cocos finch is a member of a group collectively known as

. Although traditionally placed with the buntings and

New World sparrow New World sparrows are a group of mainly New World passerine birds, forming the family Passerellidae. They are seed-eating birds with conical bills, brown or gray in color, and many species have distinctive head patterns. Although they share t ...

s in the family

molecular phylogenetic Molecular phylogenetics () is the branch of phylogeny that analyzes genetic, hereditary molecular differences, predominantly in DNA sequences, to gain information on an organism's evolutionary relationships. From these analyses, it is possible to ...

studies have shown that Darwin's finches are members of the

subfamily In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...

Coerebinae within the tanager 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 ...

. The Cocos finch was first categorized to be closer to the warbler finch

clade A clade (), also known as a monophyletic group or natural group, is a group of organisms that are monophyletic – that is, composed of a common ancestor and all its lineal descendants – on a phylogenetic tree. Rather than the English term, ...

due to the similar

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines * Morphology (archaeology), study of the shapes or forms of artifacts * Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies ...

of cousin warbler finches. The Cocos finch shares many morphological similarities to other Darwin's finches despite having been separated from the Galapagos Islands. What is unique, however, of the Cocos finch, is that they display an inter-species variation in feeding habits. The variation in foraging behaviors are hypothesized to be possible by

observational learning Observational learning is learning that occurs through observing the behavior of others. It is a form of social learning which takes various forms, based on various processes. In humans, this form of learning seems to not need reinforcement to oc ...

from other Cocos finches. These feeding specializations are independent of any morphological changes, sex and age differences, rather, they are derived from an inter-species variation found within the Cocos finch. Still, despite its variation in feeding patterns, Cocos finches are categorized as one species with no known subspecies.

Description

The Cocos finch stands at about 12 cm long weighing in at about 12.5 g. The bird has a small pointed beak for eating berries and insects that are its main diet. They are

sexually dimorphic Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most ani ...

in that the males have black feathers from the tail, breast, nape, and

crown A crown is a traditional form of head adornment, or hat, worn by monarchs as a symbol of their power and dignity. A crown is often, by extension, a symbol of the monarch's government or items endorsed by it. The word itself is used, partic ...

. Unlike male finches found in Galapagos island, male Cocos finches have black beaks year-round. Female Cocos finch have a lighter brown complexion compared to a male Cocos finch. There is a black splattering of feathers on their breast area down to the flank and rump. The belly of the female Cocos finch is milky white compared to the mantle of the bird. The nape and crown area are more noticeably black. The call of a Cocos finch can be described as a "buzzy" like sound with a high-pitched ending note. The beginning of the call can form a “djirr” sound followed by a high pitched “tiew” sound. Calls can also include a high pitched “phzzzz” sound.

Distribution and Habitat

The Cocos finch is exclusively found in Cocos Island (1,997 km² area), 580 km SE from Costa Rica. Cocos finches are not known to have traveled outside of Cocos Island making its habitat and reproduction range to only be at 30 km² within the island. The habitat of the Cocos finch is mostly within Hibiscus thickets, closed-canopy forest and woodland forest. The climate within Cocos Island is described to be a typical

rain forest Rainforests are characterized by a closed and continuous tree canopy, moisture-dependent vegetation, the presence of epiphytes and lianas and the absence of wildfire. Rainforest can be classified as tropical rainforest or temperate rainforest ...

climate with high humidity and chances for rainfall. The island has a varied landscape with bodies of lakes, streams, and caves and is home to other species including endemic lizards (only 2 species), small mice, small cats, and some migratory birds.

Ecology and Behavior

Foraging Patterns

Cocos finches known to be a

generalist species A generalist species is able to thrive in a wide variety of environmental conditions and can make use of a variety of different natural resource, resources (for example, a heterotroph with a varied diet (nutrition), diet). A specialist species can ...

, although they are also known to specialize in an individual level which can result in different foraging behaviors within individual Cocos finches. This specialized behavior of Cocos finches can be explained through learning foraging patterns through other Cocos finches and can resonate said individual behavior to other Cocos Finches.

Breeding

Cocos finch usually nest throughout the year; however, their breeding season falls usually at around January–February. They form a nest using lichen and dry moss as their main material. Eggs are in clutch sizes of about 4–5 with a distinctive pink/light brown spots.

Threats

Cocos finches face mammalian predatory encounters including native and introduced rats and cats in the island. Despite its predators, there is no evidence of high predatory pressures on the Cocos finches themselves. Scientists conclude that due to the low predatory pressures on Cocos finches, they have developed this specialized feeding behavior to evolve to a more generalist species.

Status

Cocos Island is a natural reserved island and that there is limited human interaction towards the Cocos finch and to other Cocos Island inhabitants. While there has been increasing tourism around the island, there is no evidence of high disturbance rates from these tourists to affect the wildlife in the island including the Cocos Finch. While the

predation Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...

and disturbance rate of Cocos finch are low along with a steady population rate, the

IUCN The International Union for Conservation of Nature (IUCN; officially International Union for Conservation of Nature and Natural Resources) is an international organization working in the field of nature conservation and sustainable use of natu ...

deems the Cocos finch to be least concern; about 30 km² of the whole Cocos Island. As of now, there are about 6,000-15,000 Cocos Finches living isolated in Cocos Island.

References

External links

BirdLife Species Factsheet.
{{Taxonbar, from=Q549398

Cocos finch The Cocos finch or Cocos Island finch (''Pinaroloxias inornata'') is the only one of the Darwin's finches not native to the Galápagos Islands, and the only member of the genus ''Pinaroloxias''. Sometimes classified in the family Emberizidae, m ...

Birds of Costa Rica

Endemic fauna of Costa Rica