Small tree finch

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Small tree finch
Camarhynchus parvulus.jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Thraupidae
Genus: Camarhynchus
Species:
C. parvulus
Binomial name
Camarhynchus parvulus
(Gould, 1837)
Geospiza parvula map.svg
Synonyms

Geospiza parvula

The small tree finch (Camarhynchus parvulus) is a bird species belonging to the Darwin's finch group within the tanager family Thraupidae. It has a grasping beak with curved culmens. [2] Its natural habitats are subtropical or tropical dry forests and subtropical or tropical dry shrubland. During the non-breeding season it is known to form large groups with small ground-finches.

Contents

It is an endemic species to the Galapagos islands and its conservation status has been listed as “Least Concern”. [3] However, bird counts which have been conducted since 1997 have shown a continuous decline in small tree-finch populations in the Scalesia and agricultural zones of Santa Cruz, where the small tree-finch is most abundant. Small tree-finch counts have remained stable in the transition zone (also quite abundant here) and in the less popular dry and fern zones on Santa Cruz island. [4]  A recent study has found that this species is in particularly impacted by the larvae of the parasitic avian vampire fly (Philornis downsi). [5]

Distribution

The small tree finch is found on all the main islands except Española, Genovesa, Marchena, Darwin and Wolf. It was also absent in the most recent census (2017-2018) on Rábida, Pinta and Santa Fé islands. [6]

Mating

Darwin's tree finches build display domed nests and use these to attract mates and for nesting. Male small tree finches will sing close to their nest once it has been built, to attract female small tree finches. When these arrive, they inspect the display nest by entering it. Thereafter they will either choose to accept both the male and the display nest, accept the male but reject the nest (so they will then build a new nest together), or reject both the male and the display nest. [7]

Older males build more concealed nests, typically higher within the tree canopy, compared to younger males which reduced predation on the nests. Females preferentially choose to breed with older males with whom they have higher fledging success compared to younger males. In a study by Kleindorfer (2007), predation accounted for 60% of nest loss, making it a strong selective force. Males with high vocal performance, which is predicted by beak morphology, also have higher pairing success. There is also evidence for size-assortative pairing based on beak and tarsus length. Thus multiple factors influence pairing success in small tree finches: male and female body and beak size, male vocal performance, nest concealment, and male age. [7]

Colouration

Small tree finches moult annually. Female small tree finches are grey/brown throughout their lives. Male ground finches are born grey/brown, similar to females, but through a pattern of annual moult, attain a black crown and chin (the upper part of their body). Age difference can be assessed in males by observing the darkness of their crown and chin. [7]

Feeding

The small tree-finch is a mainly insectivorous bird, although has a varied diet. Typically, it gleans arthropods and leaves from bark surfaces, but 42% of its diet consists of vegetable matter (nectar, fruits and seeds). [2]

Related Research Articles

<span class="mw-page-title-main">Darwin's finches</span> Group of related bird species in the Galápagos Islands

Darwin's 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 tribe Geospizini. They belong to the tanager family and are not closely related to the true finches. The closest known relative of the Galápagos finches is the South American dull-coloured grassquit. They were first collected when the second voyage of the Beagle visited the Galápagos Islands, with Charles Darwin on board as a gentleman naturalist. Apart from the Cocos finch, which is from Cocos Island, the others are found only on the Galápagos Islands.

<span class="mw-page-title-main">Galapagos hawk</span> Species of bird

The Galápagos hawk is a large hawk endemic to most of the Galápagos Islands.

<span class="mw-page-title-main">Vampire ground finch</span> Species of bird

The vampire ground finch is a small bird native to the Galápagos Islands. It was considered a very distinct subspecies of the sharp-beaked ground finch endemic to Wolf and Darwin Islands. The International Ornithologists' Union has split the species supported by strong genetic evidence that they are not closely related, and divergences in morphology and song. Other taxonomic authorities still consider it conspecific.

<span class="mw-page-title-main">Woodpecker finch</span> Species of bird

The woodpecker finch is a monomorphic species of bird in the Darwin's finch group of the tanager family, Thraupidae endemic to the Galapagos Islands. The diet of a woodpecker finch revolves mostly around invertebrates, but also encompasses a variety of seeds. Woodpecker finches, like many other species of birds, form breeding pairs and care for young until they have fledged. The most distinctive characteristic of woodpecker finches is their ability to use tools for foraging. This behaviour indicates that they have highly specialized cognitive abilities. Woodpecker finches have also shown the ability to learn new behaviours regarding tool use via social learning. Not all populations of woodpecker finches use tools equally often, as this is influenced by the environment in which they live.

<span class="mw-page-title-main">Mangrove finch</span> Species of bird

The mangrove finch is a species of bird in the Darwin's finch group of the tanager family Thraupidae. It is endemic to the Galápagos Islands. It was found on the islands of Fernandina and Isabela, but recent surveys have failed to record the species on Fernandina. It has been classified as critically endangered by BirdLife International, with an estimated population of 20–40 mature individuals in 2021, located in two large mangroves on Isabela. A study has shown that the two small populations remaining on Isabela Island have begun undergoing speciation and that one or both populations will eventually become extinct due to a lack of interbreeding.

<span class="mw-page-title-main">Medium tree finch</span> Species of bird

The medium tree finch is a critically endangered species of bird in the Darwin's finch group of the tanager family Thraupidae. It is endemic to the Galápagos Islands where it is only found on Floreana Island. Its name is derived from the fact that the bird's beak is intermediate in size between that of the small tree finch and the large tree finch. Because it has a very small range on a single island, and because of the introduction of a parasitic fly which kills the nestlings, the International Union for Conservation of Nature has rated the medium tree finch as "critically endangered".

<span class="mw-page-title-main">Large tree finch</span> Species of bird

The large tree finch is a species of bird in the Darwin's finch group of the tanager family Thraupidae. It is endemic to the Galapagos Islands.

<span class="mw-page-title-main">Sharp-beaked ground finch</span> Species of bird

The sharp-beaked ground finch is a species of bird in the Darwin's finch group of the tanager family Thraupidae. It is classified as a least-concern species by the International Union for Conservation of Nature and it is native to the Galápagos Islands in Ecuador. It has a mass of around 20 grams (0.71 oz) and the males have black plumage, while females have streaked brown plumage. This finch was described by Richard Bowdler Sharpe in 1888.

<span class="mw-page-title-main">Medium ground finch</span> Species of bird

The medium ground finch is a species of bird in the family Thraupidae. It is endemic to the Galapagos Islands. Its primary natural habitat is tropical shrubland. One of Darwin's finches, the species was the first which scientists have observed evolving in real-time.

<span class="mw-page-title-main">Small ground finch</span> Species of bird

The small ground finch is a species of bird in the tanager family Thraupidae. Endemic to the Galápagos Islands, it is common and widespread in shrubland, woodland, and other habitats on most islands in the archipelago. It commonly feeds on small seeds and parasites from the skins of Galápagos land and marine iguanas and Galápagos tortoises.

<span class="mw-page-title-main">Large ground finch</span> Species of bird

The large ground finch 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 of most of the archipelago, though it is absent from the southeastern islands. It is the largest species of Darwin's finch both in total size and size of beak. It has a large, stubby beak for cracking and consuming nuts.

<span class="mw-page-title-main">Common cactus finch</span> Species of bird

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. Most of these islands are inhabited by its close relative, the Española cactus finch.

<span class="mw-page-title-main">Galápagos mockingbird</span> Species of bird

The Galápagos mockingbird is a species of bird in the family Mimidae. It is endemic to the Galápagos Islands, Ecuador.

<span class="mw-page-title-main">Vegetarian finch</span> Species of bird

The vegetarian finch is a species of bird in the Darwin's finch group of the tanager family Thraupidae endemic to the Galápagos Islands. It is the only member of the genus Platyspiza.

<span class="mw-page-title-main">Lava heron</span> Species of bird

The lava heron, also known as the Galápagos heron, is a species of heron endemic to the Galápagos Islands of Ecuador. It is considered by some authorities — including the American Ornithological Society and BirdLife International — to be a subspecies of the striated heron, and was formerly "lumped" with this species and the green heron as the green-backed heron.

<i>Philornis downsi</i> Species of fly

Philornis downsi, also known as the avian vampire fly, is a species of fly that was first recorded in Trinidad and Brazil in the 1990s. It has been accidentally introduced to the Galapagos Islands (Ecuador). Adults of P. downsi feed on fruit. Eggs are laid in bird nests and hatch into parasitic larvae that reside in the nest material and emerge at night to feed both internally and externally on the blood and flesh of developing nestlings. The parasite causes significant mortality in Darwin's finch nestlings and threatens the survival of some rarer species such as the mangrove finch and the medium tree finch. To protect the threatened finch populations, insecticide-laced cotton has been supplied as nesting material for the finches, with the results being highly successful in combating P. downsi infestations at a localized scale. Currently, Biological pest control agents, including Conuraannulifera, are being investigated for their potential safety and efficacy in eradicating P. downsi on the Galapagos Islands.

<span class="mw-page-title-main">Española cactus finch</span> Species of bird

The Española cactus finch, is a species of bird in the tanager family Thraupidae. It is one of Darwin's finches, and is endemic 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.

Cerro Pajas is an inactive volcano located in the south of Floreana Island in the Galápagos Islands, Ecuador. It is the highest peak on Floreana, with a maximum elevation of 640 meters above sea level.

Asilo de la Paz is a location on Floreana Island in the Galapagos archipelago. It is the site of Floreana's first human settlement, and is now among the island's most popular tourist attractions. The site has a maximum elevation of 450 meters above sea level.

References

  1. BirdLife International (2012). "Geospiza parvula". IUCN Red List of Threatened Species . 2012. Retrieved 26 November 2013.
  2. 1 2 Tebbich, Sabine; Taborsky, Michael; Fessl, Birgit; Dvorak, Michael; Winkler, Hans (2004-02-01). "Feeding Behavior of Four Arboreal Darwin's Finches: Adaptations to Spatial and Seasonal Variability". The Condor. 106 (1): 95–105. doi: 10.1093/condor/106.1.95 . ISSN   0010-5422.
  3. BirdLife International (2021). "Species factsheet: Geospiza parvula". BirdLife International. Retrieved 1 March 2021.
  4. Dvorak, Michael; Fessl, Birgit; Nemeth, Erwin; Kleindorfer, Sonia; Tebbich, Sabine (January 2012). "Distribution and abundance of Darwin's finches and other land birds on Santa Cruz Island, Galápagos: evidence for declining populations". Oryx. 46 (1): 78–86. doi: 10.1017/S0030605311000597 . ISSN   0030-6053.
  5. Cimadom, Arno; Tebbich, Sabine (January 2021). "Timing of infestation influences virulence and parasite success in a dynamic multi-host–parasite interaction between the invasive parasite, Philornis downsi, and Darwin's finches". Oecologia. 195 (1): 249–259. Bibcode:2021Oecol.195..249C. doi:10.1007/s00442-020-04807-5. ISSN   0029-8549. PMC   7882474 . PMID   33258992.
  6. Kleindorfer, Sonia; Fessl, Birgit; Peters, Katharina; Anchundia, David (2018). Field Guide: Resident landbirds of Galapagos. Charles Darwin Foundation. ISBN   978-9978-53-063-4.
  7. 1 2 3 Kleindorfer, Sonia (October 2007). "Nesting success in Darwin's small tree finch, Camarhynchus parvulus: evidence of female preference for older males and more concealed nests". Animal Behaviour. 74 (4): 795–804. doi:10.1016/j.anbehav.2007.01.020. S2CID   53205559.