Vegetarian finch (Platyspiza crassirostris)

Description

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Vegetarian finch fact file

• Description
• Biology
• Range
• Habitat
• Status
• Threats
• Conservation
• Find out more
• Glossary
• References
• Print factsheet

Vegetarian finch description

The vegetarian finch is one of a group of fourteen closely related small birds collectively known as Darwin’s finches, which are famous as an example of how different species can evolve from a single lineage ⁽²⁾. Believed to be one of the earliest of the group to diverge ^{(4) (5)}, and the only member within its genus, the relatively drab appearance of the vegetarian finch, as with all Darwin’s finches, belies the importance of the group in the development of evolutionary theory ⁽⁶⁾. The vegetarian finch is mottled brown, with a black head in the male ^{(3) (6)}, and like the other species has a rather short and rounded wings and tail ^{(2) (6)}.

Each of Darwin’s finches possesses a unique beak shape, specialised according to the species’ diet ^{(2) (7)}. The beak of the vegetarian finch is somewhat reminiscent of that of a parrot, being short and thick, with a distinctly downward-curving upper mandible and a biting tip ^{(6) (8)}. Most species of Darwin’s finches have a yellowish beak which turns black during the breeding season ⁽⁶⁾.

Synonyms

Camarhynchus crassirostris.

Weight

34 g ^{(2) (3)}

Vegetarian finch biology

As its common name suggests, the vegetarian finch feeds almost entirely on plant matter, including buds, leaves, flowers, fruits and seeds, although a few insects may occasionally be taken ^{(2) (8) (9)}. The species also has the unique habit of stripping bark from developing twigs of Croton scouleri in order to reach the sugar-rich insides ⁽⁹⁾. Feeding takes place mainly in the trees, although the birds may sometimes come to the ground to feed on young leaves and fallen fruit ⁽⁸⁾.

Darwin’s finches typically breed during the hot and wet season, when food is most abundant, although breeding is opportunistic and closely tied to rainfall ⁽²⁾. Pairs are usually monogamous, but mate changes and multiple mates have also been observed. The nest is usually dome-shaped, with a side entrance, and built out of dry grass in a cactus or bush. The male finch may build a display nest to attract a mate, before both the male and female jointly construct the actual nest ⁽²⁾. Darwin’s finches usually lay around three eggs, which are incubated by the female for about 12 days. The young leave the nest after about two weeks, and the breeding pair may raise several broods each year if environmental conditions are favourable ⁽²⁾. The comparatively small clutches, small-sized eggs and short incubation periods of Darwin’s finches are thought to be adaptations allowing repeated, rapid breeding when conditions allow ⁽¹⁰⁾. The breeding pair may maintain a small territory during the breeding season, but often forage in large, mixed-species flocks at other times ⁽²⁾.

Vegetarian finch range

The vegetarian finch is endemic to the Galapagos Islands, where it occurs on the islands of Isabela, Santa Cruz, Fernandina, Santiago, San Cristóbal, Floreana, Marchena and Pinta ^{(4) (6)}.

Vegetarian finch habitat

The vegetarian finch occurs mainly in transition forest at middle elevations, and also in forest at higher elevations ^{(2) (4)}.

Vegetarian finch status

The vegetarian finch is classified as Least Concern (LC) on the IUCN Red List ⁽¹⁾.

Vegetarian finch threats

Although believed to be relatively common and not thought to be undergoing a large population decline ⁽¹¹⁾, the vegetarian finch may be vulnerable to a range of factors threatening the Galapagos Islands. These include habitat destruction, increasing tourism and associated human population growth, and introduction of non-native predators and competitors ^{(2) (7) (12)}. In particular, Darwin’s finches are under threat from the introduction of diseases such as Avian pox and nest parasites, such as the fly Philornis downsi, to which the species are not adapted ^{(2) (7)}.

Vegetarian finch conservation

The Galapagos Islands are part of the Galapagos Islands National Park, designated a World Heritage Site. A management plan is in place for the islands, and the Ecuadorian government is working to conserve the unique Galapagos wildlife ⁽¹²⁾. In addition, scientists from the Charles Darwin Research Station are working to monitor and improve understanding of Darwin’s finch populations, in order to help guide the conservation of these iconic birds ⁽⁷⁾.

Find out more

To find out more about the conservation of Darwin’s finches and other Galapagos wildlife see:

• Charles Darwin Foundation:
  http://www.darwinfoundation.org

For more information on this and other bird species please see:

• BirdLife International:
  http://www.birdlife.org

Authentication

Glossary

Endemic

A species or taxonomic group that is only found in one particular country or geographic area.

Genus

A category used in taxonomy, which is below ‘family’ and above ‘species’. A genus tends to contain species that have characteristics in common. The genus forms the first part of a ‘binomial’ Latin species name; the second part is the specific name.

Incubation

The act of incubating eggs, that is, keeping them warm so that development is possible.

Mandible

In birds, the lower jaw and beak, but the term is also used to denote the two parts of the beak.

Monogamous

Having only one mate during a breeding season, or throughout the breeding life of a pair.

Territory

An area occupied and defended by an animal, a pair of animals or a colony.

References

1. IUCN Red List (March, 2009)
   http://www.iucnredlist.org
2. Hau, M. and Wikelski, M. (2001) Darwin’s Finches. In: Encyclopedia of Life Sciences. John Wiley & Sons, Chichester.
3. Grant, P.R. (1999) Ecology and Evolution of Darwin’s Finches. Princeton University Press, Princeton, New Jersey.
4. Grant, P.R. and Grant, B.R. (2007) How and Why Species Multiply: The Radiation of Darwin’s Finches. Princeton University Press, Princeton, New Jersey.
5. Sato, A., O’hUigin, C., Figueroa, F., Grant, P.R., Grant, B.R., Tichy, H. and Klein, J. (1999) Phylogeny of Darwin’s finches as revealed by mtDNA sequences. Proc. Natl. Acad. Sci. USA, 96: 5101 - 5106.
6. Jackson, M.H. (1993) Galápagos: A Natural History. University of Calgary Press, Calgary.
7. Charles Darwin Foundation (May, 2009)
   http://www.darwinfoundation.org/files/species/pdf/finches-en.pdf
8. Lack, D. (1983) Darwin’s Finches. Cambridge University Press, Cambridge.
9. Grant, B.R. and Grant, P.R. (1989) Evolutionary Dynamics of a Natural Population: The Large Cactus Finch of the Galapagos. University of Chicago Press, Chicago, Illinois.
10. Grant, P.R. (1982) Variation in the size and shape of Darwin’s finch eggs. The Auk, 99(1): 15 - 23.
11. BirdLife International (May, 2009)
    http://www.birdlife.org/datazone/species/index.html?action=SpcHTMDetails.asp&sid=9607&m=0
12. UNEP-WCMC: Galápagos Islands National Park and Marine Reserve, Ecuador (May, 2009)
    http://www.unep-wcmc.org/medialibrary/2011/06/28/62f3bab1/Galapagos%20Islands.pdf