Kokosinsel-Darwinfink

Bestimmung

The Cocos finch stands at about 12 cm long weighing in at about 12.5 g. The bird has a black decurved pointed bill for eating berries and insects that are its main diet. They are sexually dimorphic in that the males have almost entirely black, having black feathers from the tail, breast, nape, and crown. Unlike male finches found on the Galapágos islands, male Cocos finches have black beaks year-round, never changing color.<p>Female Cocos finches have a lighter brown complexion compared to males. 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 young are similar, but have yellow bills.<p>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.

Taxonomie

The Cocos finch was formally described in 1843 by the English ornithologist John Gould under the binomial name Cactornis inornatus. The species was moved to a new genus Pinaroloxias by Richard Bowdler Sharpe in 1885. The genus name combines the Ancient Greek pinaros meaning "dirty" or "squalid" with Loxia, a genus introduced by Carl Linnaeus in 1758 for the crossbills. The specific epithet inornata is Latin for "plain" or "unadorned". The Cocos finch is a member of a group collectively known as Darwin's finches. Although traditionally placed with the buntings and New World sparrows in the family Emberizidae, molecular phylogenetic studies have shown that Darwin's finches are members of the subfamily Coerebinae within the tanager family Thraupidae. The Cocos finch was first categorized to be closer to the warbler finch clade due to the similar morphology of cousin warbler finches.<p>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 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.

Wissenschaftlicher Name

Pinaroloxias inornata

Autorität

(Gould, 1843)

Ordnung

Passeriformes

Familie

Thraupidae

Gattung

Pinaroloxias

Verbreitung und Lebensraum

The Cocos finch is exclusively found in Cocos Island (which takes up a 1,997 km2 area), 580 km southeast from Costa Rica. Cocos finches are not known to have traveled outside of Cocos Island making its habitat and reproduction range to only be 30 km2 of the entire island. The habitat of the Cocos finch is mostly within Hibiscus thickets, closed-canopy forest and woodland forest.<p>The climate within Cocos Island is described to be a typical rain forest 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) and some migratory birds.

Zugverhalten

Standvogel

Verhalten

Zugverhalten: Standvogel.

Schutzstatus

Bestandstrend: stabil.

Bestandstrend

stabil