Black-bellied seedcracker

Last updated

Black-bellied seedcracker
Black-bellied Seedcracker - Kakum - Ghana S4E2847 (22799387200).jpg
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Chordata
Class: Aves
Order: Passeriformes
Family: Estrildidae
Genus: Pyrenestes
Species:
P. ostrinus
Binomial name
Pyrenestes ostrinus
(Vieillot, 1805)

Spiza americana male 94 231051626 13e01e8125 o cropped flipped.png

Songs and calls
Listen to a black-bellied seedcracker on xeno-canto

The black-bellied seedcracker (Pyrenestes ostrinus) is a bird species of the family Estrildidae. They live in most Central African countries and inhabit tropical rainforest. The species comprises individuals with different physical appearance which are grouped into three categories (small, large and mega bill size). [2] Adults are mainly granivorous but diet preference varies with bill size and food availability. [3] Black-bellied seedcrackers also exhibit very distinctive colorations with bright patches of black and red, making them easy to identify in the field. Overall, little is known about this species apart from its range, but intensive studies are currently looking at bill size variations among individuals and their effects on behaviors. [4]

Contents

Taxonomy

Black-bellied seedcracker is one of the 27 African species of finch out of 141 worldwide. [5] They are thought to originate from India and South Asia and would have expanded in Africa over time with continental dynamics and tectonic activities. [6] [7] Finches belong to the family Estrilidae, within the order Passeriformes. [8] They are considered a monophyletic clade, meaning that from an evolutionary perspective, finches in the family Estrilidae constitute all the descendants of a common ancestor.

The species was first identified by Vieillot who formerly named it Loxia ostrina in 1805. However, in 1937, when Swainson reviewed the taxonomy and phylogeny of African finches, the species was moved to another genus and renamed Pyrenestes ostrinus. [9] [6] They are close relatives of crimson seedcrackers (Pyrenestes sanguineus) [10] and lesser seedcrackers (Pyrenestes minor), [11] two other similar African species of finch. However ranges barely overlap between those three species: Crimson seedcrackers live in Western African countries but north to Black-bellied seedcrackers. As for Lesser seedcrackers, they cover Eastern African countries. [12] [11]

Description

Black-bellied seedcrackers are small passerine birds, measuring about 15 cm [6] and exhibiting the typical silhouette of finch family members. The species is quite common across its range and easy to identify due to its body coloration which also earned its name. Indeed, a black bright patch covers its belly and back, and stands out against the redness of its head, chest and tail. [12] There is a slight difference in coloration between sexes: where males exhibit those intense black patches, females are colored in dull brown. [12] Females also tend to be smaller in size. [3] A short and conical or large-based beak, combined with big circular and centered eyes give the visual impression of a small and stocky head [12]

Polymorphism

Different variations among individuals, referred to as morphs, have been discovered in these last 50 years and constitute a current intensive field of research. [13] This variability of the phenotype (physical appearance) is called polymorphism and concerns bill size of black-bellied seedcrackers. Yet, two morphs have been established: large-billed individuals and small-billed ones. A third type is thought to arise with an even larger beak called mega-billed morph but more data are needed to reach a universal agreement on whether or not it is different from the large-billed morph. [13] [2] [14] Contrarily to most cases of polymorphisms in nature, bill-size variation in black-bellied seedcrackers isn't related to sex but instead seems to correlate with diet. [4] The common hypothesis suggests that a small gene mutation occurred, and had a large impact on the morphology of individuals. Emergence of variations among individuals of a species is part of evolutionary processes. Having the ability to observe such phenomenon on a human scale is a real opportunity to try to understand those mechanisms better. [13] [15] Over time, this mutation could separate two extreme morphs into two distinct species in a process called disruptive selection. [16]

Habitat

Black-bellied seedcrackers inhabit tropical rainforest of Africa and nest in moist environments, near swamps, marsh, ponds, wet prairies and in moist broadleaf forest. However, they also occupy drier habitats such as dry broadleaf forest, grassland, savanna and shrubland. [17] [18] They are a very adaptable species. As a matter of fact, in locations contiguous to urban built-up areas, black-bellied seedcrackers are found in numbers in plantations (especially cacao) that offer high quality nesting branches. [18] They are also common garden birds and benefit from feeders. Thus, the proximity to humans does not seem to negatively alter their population.

Distribution

Black-bellied seedcrackers are native to Central Africa and resident birds, meaning they do not migrate over the seasons. Although little record exists for their historical home range, it is thought that it has not variated much over time. The last assessment, in 2016, showed the species occupies a wide range and is present in SE Ivory Coast, Ghana, Togo, Benin, South Sudan, Nigeria, Equatorial Guinea, Western and Southern Cameroon, Central African Republic, SW Chad, Gabon, Democratic Republic of Congo, Republic of Congo, Uganda, W Kenya, Angola, Zambia and SW Tanzania. [12] [19] [1]

Population trend and conservation status

There is few historical records of black-bellied seedcracker population size. The first COSEWIC assessment of the species was made in 1988, and until 2000 the species was classified under lower risk/ least concerned category. [1] In 2004, the species was reassessed and simply moved to the least concerned list. [1] The 2016 population examination maintained this conservational status. [1] Although the population size in unknown, it is thought to be relatively stable and not particularly threatened, black-bellied seedcracker being quite common birds within their range. Trends of their population and home range sizes have been modelized in relation to climate change for the next 67 years and although home range would slightly decrease on the borders, it is not concerning for the conservation of the species. [20] [21] Nowadays, the main threats faced by black-bellied seedcrackers emanate from nest predation by rats, snakes [4] and feral cats, habitat over harvest and window collisions (increasing with urbanization).

Behavior

Vocalization

Black-bellied seedcrackers, like most finches, are very social birds and thus maintain strong vocal bonds. They use calls made of low "peenk" to keep contact with each other while foraging or not in sighting positions, whereas their alarm call comprises "terr" sounds. Those are the common vocalization of black-bellied seedcrackers.

However, during the breeding period, going from March to October, they often sing as part of courtship display to attract a mate. [22] Compared to other finches, they exhibit very complex songs. Their repertoire contains one to seven song types with 5 to 30 notes per song and a high variability among individuals. A song comports a series of repeated sounds, meaning an individual will sing identical notes multiple times, then switch to others, repeat them and switch again to others. [22] The tone often varies from one individual to another and from one song to another. In addition, records of black-bellied seedcrackers show the species has the ability to produce double voice sounds, increasing complexity and diversity of their songs. Males and females sound alike except males usually sing more frequently. [6] [22]

Since two morphs are definitely established, scientists are looking at the effect of bill size on songs and courtship display (resonance, tonality, complexity). The average song frequency is 7 Hz. Hypotheses are that bill morphology influences songs in very subtle ways audible by potential mates; however, up until now studies remain inconclusive. [22]

Diet

Diet is the second factor earning black-bellied seedcrackers their name. Adults feed on seeds that they open thanks to their hard beak. All of them mostly eat seeds from sedges, bushes from the genus Scleria . [13] Depending on the season, the abundance of food and their bill morphology (small or large bill size), black-bellied seedcrackers broaden or specialize their diet. For example in periods of abundance, all individuals feed on various seeds, berries, insects, and few green leaves. However, in periods of scarcity, small-billed individuals specialized on soft seeds of sedge (Scleria goossensii), whereas large-billed morphs will go for hard seeds of sedge (Scleria verrucosa). [13] Concerning the emerging mega morph, their larger beak allows them to open seeds of Scleria racemosa, a sedge species with an even harder shell. So all morphs coexist and really differ by their diet specificity in periods of food scarcity. [13] Last, although the species is mostly granivorous, parents will feed juveniles with soft insects until the beak is completely formed and hardened. [13] [18]

Reproduction

Breeding season of black-bellied seedcrackers runs from March to November, peaking in April and September and coincides with rain seasons. [22] It begins with courtship behaviors. Males show off by holding a piece of vegetation in their bill, like a long grass blade, leaf or grass panicle, and bob up and down perched in trees. Simultaneously, they sing to advertise their presence and attract females. [18] Females are the one choosing their mate based on this display. This system in which one mate has complete choice over the other sex is called epigamic selection and is a common characteristic in the finch family. Mates stay together the entire breeding season and will build a nest a few meters from the ground using leaves. Although there is an overall synchronization among individuals for the entire breeding period and reproductive peaks, pairs differ in the timing and number of hatchings. Some will produce one hatching and others two throughout the year. Some also raise young in May, at the beginning of the breeding season, others around July and still others in October, toward the end of the season. [4] [18] A female lays in average 2 to 4 eggs and both parents take shifts to brood. [18] Chicks hatch about 16 days later and parents will keep alternating to feed them. Young are altricial, meaning they are not directly independent. They stay about a month in the nest before taking off and foraging by themselves. [18] The main cause of nest failure is due to predation (rats and snakes). [4] [18]

Interestingly, black-bellied seedcrackers breed regardless of bill morphs (either small-billed pairs, large-billed pairs or pairs with one individual of each morph), but no intermediate bill size arises from offspring of crosses between morphs. [18] As a matter of fact, offspring from two small-billed parents have a small bill, large-billed pairs produce large-billed chicks, and crosses between morphs give rise to either large or small-billed individuals. So morphs are completely related to diet and not sexual selection.

Related Research Articles

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

The dunlin is a small wader in the genus Calidris. The English name is a dialect form of "dunling", first recorded in 1531–1532. It derives from dun, "dull brown", with the suffix -ling, meaning a person or thing with the given quality.

<span class="mw-page-title-main">Ruff (bird)</span> Species of bird

The ruff is a medium-sized wading bird that breeds in marshes and wet meadows across northern Eurasia. This highly gregarious sandpiper is migratory and sometimes forms huge flocks in its winter grounds, which include southern and western Europe, Africa, southern Asia and Australia.

<span class="mw-page-title-main">Eurasian siskin</span> Species of bird

The Eurasian siskin is a small passerine bird in the finch family Fringillidae. It is also called the European siskin, common siskin or just siskin. Other (archaic) names include black-headed goldfinch, barley bird and aberdevine. It is very common throughout Europe and Eurosiberia. It is found in forested areas, both coniferous and mixed woodland where it feeds on seeds of all kinds, especially of alder and conifers.

<span class="mw-page-title-main">Pine siskin</span> Species of bird

The pine siskin is a North American bird in the finch family. It is a migratory bird with an extremely sporadic winter range.

<span class="mw-page-title-main">Fork-tailed drongo</span> Species of bird

The fork-tailed drongo, also called the common drongo or African drongo, is a small bird found from the Sahel to South Africa that lives in wooded habitats, particularly woodlands and savannas. It is part of the family Dicruridae and has four recognized subspecies, D. a adsimilis, D. a. apivorus, D. a. fugax and D. a. jubaensis. Like other drongos, the fork-tailed is mostly insectivorous; its diet mainly consists of butterflies, termites, and grasshoppers.

<span class="mw-page-title-main">Disruptive selection</span> Natural selection for extreme trait values over intermediate ones

In evolutionary biology, disruptive selection, also called diversifying selection, describes changes in population genetics in which extreme values for a trait are favored over intermediate values. In this case, the variance of the trait increases and the population is divided into two distinct groups. In this more individuals acquire peripheral character value at both ends of the distribution curve.

<span class="mw-page-title-main">Crimson seedcracker</span> Species of African finch

The crimson seedcracker is a common species of estrildid finch found in Africa. It has an estimated global extent of occurrence of 834,000 km2 (322,000 sq mi). It is found in Burkina Faso, Côte d'Ivoire, Gambia, Guinea, Guinea-Bissau, Liberia, Mali, Senegal and Sierra Leone. The International Union for Conservation of Nature has classified the species as being of least concern.

The lesser seedcracker or Nyasa seedcracker is a fairly common species of estrildid finch found in eastern Africa. It has an estimated global extent of occurrence of 925,000 km2 (357,000 sq mi) and is found in Malawi, Mozambique, Tanzania and Zimbabwe. The International Union for Conservation of Nature has classified the species as being of least concern.

<span class="mw-page-title-main">Rock firefinch</span> Species of bird

The rock firefinch is a species of estrildid finch found in the Jos Plateau of central Nigeria and in Cameroon. It has an estimated global extent of occurrence of 29,000 km2. The rock firefinch was discovered recently, in 1998. Rock firefinches fall in the family Estrildidae, which contains small passerine birds of the Old World and Australasia. Rock firefinches seem to be most closely related to Mali firefinches and Chad firefinches. The species name sanguinodorsalis means blood-red back, which was chosen because it describes the vibrant red back color of the male plumage. The status of the species is evaluated as Least Concern.

<span class="mw-page-title-main">White-cheeked bullfinch</span> Species of bird

The white-cheeked bullfinch is a species of finch in the family Fringillidae. It is found in mountain regions of the Philippines on the islands of Luzon and Mindanao. It has also been reported on the island of Panay. Its natural habitat is tropical moist montane forests above 1,250 meters above sea level. It is the only bullfinch found in the Philippines.

<span class="mw-page-title-main">Black sparrowhawk</span> Species of bird

The black sparrowhawk, sometimes known as the black goshawk or great sparrowhawk, is a bird of prey belonging to the family Accipitridae. It was formerly placed in the genus Accipiter. It occurs mainly in forest and non-desert areas south of the Sahara, particularly where there are large trees suitable for nesting; favored habitat includes suburban and human-altered landscapes. It preys predominantly on birds of moderate size, such as pigeons and doves, in suburban areas.

<span class="mw-page-title-main">Collared owlet</span> Species of owl

The collared owlet, also known as the collared pygmy owl, is a species of owl in the family Strigidae. Its natural habitat is submontane and montane forests with open spaces and is distributed throughout oriental Asia. It is the smallest owl in Asia, at 15 cm (5.9 in) and 60 g (2.1 oz).

<span class="mw-page-title-main">Black-backed dwarf kingfisher</span> Species of bird

The black-backed dwarf kingfisher, also known as the three-toed kingfisher, is a pocket-sized bird in the family Alcedinidae. It was formerly considered as conspecific with the rufous-backed dwarf kingfisher and together the species complex was known by the English name "oriental dwarf kingfisher".

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

The great-billed seed finch is a species of bird in the family Thraupidae. Its natural habitats are subtropical or tropical moist shrubland, swamps, and heavily degraded former forest. They are found in two separate general populations, one in the northern Amazon rainforest and the other in the Cerrado. They live in flooded areas with nests low to the ground. The adults express strong sexual dimorphism. Males are black with white under wing-coverts and ivory white bills, and the females are generally light brown with white under wing-coverts and black bills. Both the male and female have very large, thick bills. The great-billed seed finch has a melodious call, which has made it a target for trapping.

<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">Orange weaver</span> Species of bird

The orange weaver is a species of bird in the weaver family, Ploceidae. It is sparsely distributed across African tropical rainforest.

References

  1. 1 2 3 4 5 BirdLife International (2018). "Pyrenestes ostrinus". IUCN Red List of Threatened Species . 2018: e.T22719384A132128345. doi: 10.2305/IUCN.UK.2018-2.RLTS.T22719384A132128345.en . Retrieved 12 November 2021.
  2. 1 2 Smith, Thomas B. (2008-06-28). "Adaptive significance of the mega-billed form in the polymorphic Black-bellied Seedcracker Pyrenestes ostrinus". Ibis. 139 (2): 382–387. doi: 10.1111/j.1474-919x.1997.tb04638.x . ISSN   0019-1019.
  3. 1 2 Smith, Thomas Bates (1987). "Bill size polymorphism and intraspecific niche utilization in an African finch". Nature. 329 (6141): 717–719. doi:10.1038/329717a0. ISSN   0028-0836. S2CID   4235946.
  4. 1 2 3 4 5 Frampton, Tracy (2007-12-18). "Captive breeding of Black-bellied seedcrackers Pyrenestes ostrinus at Riverbanks Zoo". International Zoo Yearbook. 27 (1): 270–272. doi:10.1111/j.1748-1090.1988.tb03222.x. ISSN   0074-9664.
  5. ↑ Rose, Sanjo; Oschadleus, H Dieter (2017-12-20). "Longevity summary from 69 years of Estrildidae ringing data in southern Africa". African Zoology. 53 (1): 41–46. doi:10.1080/15627020.2017.1413953. ISSN   1562-7020. S2CID   89962433.
  6. 1 2 3 4 "Black-bellied Seedcracker (Pyrenestes ostrinus)". Birds of the World. Retrieved 2018-09-29.
  7. ↑ Sibley CG, Ahlquist JE (1990). Phylogeny and Classification of Birds. USA: Yale University Press. pp. 703–704. ISBN   0-300-04085-7.
  8. ↑ Sibley CG, Ahlquist JE (1990). Phylogeny and Classification of Birds. USA: Yale University Press. pp. 565–577, 683–690, 854–855. ISBN   0-300-04085-7.
  9. ↑ "ITIS Standard Report Page: Pyrenestes ostrinus". www.itis.gov. Retrieved 2018-09-29.
  10. ↑ BirdLife International (2018). "Pyrenestes sanguineus". IUCN Red List of Threatened Species . 2018: e.T22719379A132128125. doi: 10.2305/IUCN.UK.2018-2.RLTS.T22719379A132128125.en . Retrieved 12 November 2021.
  11. 1 2 BirdLife International (2016). "Pyrenestes minor". IUCN Red List of Threatened Species . 2016: e.T22719389A94625359. doi: 10.2305/IUCN.UK.2016-3.RLTS.T22719389A94625359.en . Retrieved 12 November 2021.
  12. 1 2 3 4 5 Borrow N, Demey R (2004). Birds of Western Africa. New Jersey (USA): Princeton University Press. pp. 454–450. ISBN   978-0-691-12321-9.
  13. 1 2 3 4 5 6 7 Clabaut, Celine; Herrel, Anthony; Sanger, Thomas J.; Smith, Thomas B.; Abzhanov, Arhat (2009). "Development of beak polymorphism in the African seedcracker, Pyrenestes ostrinus". Evolution & Development. 11 (6): 636–646. CiteSeerX   10.1.1.395.5771 . doi:10.1111/j.1525-142x.2009.00371.x. ISSN   1520-541X. PMID   19878285. S2CID   1399855.
  14. ↑ Mousseau, Timothy A.; Sinervo, Professor Department of Ecology and Evolutionary Biology Barry; Sinervo, Barry; Endler, John A. (2000-01-13). Adaptive Genetic Variation in the Wild. Oxford University Press, USA. pp. 140–151. ISBN   9780195121834.
  15. ↑ Smith, Thomas Bates (1990). "Natural Selection on Bill Characters in the Two Bill Morphs of the African Finch Pyrenestes ostrinus". Evolution. 44 (4): 832–842. doi: 10.1111/j.1558-5646.1990.tb03808.x . ISSN   0014-3820. PMID   28569017.
  16. ↑ Smith, Thomas Bates (1990). "Patterns of morphological and geographic variation in trophic bill morphs of the African finch Pyrenestes". Biological Journal of the Linnean Society. 41 (4): 381–414. doi:10.1111/j.1095-8312.1990.tb00842.x. ISSN   0024-4066.
  17. ↑ "Black-bellied Seedcracker - Pyrenestes ostrinus - Overview". Encyclopedia of Life. Retrieved 2018-09-30.
  18. 1 2 3 4 5 6 7 8 9 Smith, Thomas Bates (1990). "Comparative Breeding Biology of the Two Bill Morphs of the Black-Bellied Seedcracker". The Auk. 107 (1): 153–160. JSTOR   4087813.
  19. ↑ "Black-bellied Seedcracker (Pyrenestes ostrinus) - BirdLife species factsheet". datazone.birdlife.org. Retrieved 2018-10-01.
  20. ↑ "Black-bellied Seedcracker (Pyrenestes ostrinus) - BirdLife species factsheet". datazone.birdlife.org. Retrieved 2018-10-01.
  21. ↑ Hole, David G.; Willis, Stephen G.; Pain, Deborah J.; Fishpool, Lincoln D.; Butchart, Stuart H. M.; Collingham, Yvonne C.; Rahbek, Carsten; Huntley, Brian (2009). "Projected impacts of climate change on a continent-wide protected area network". Ecology Letters. 12 (5): 420–431. doi:10.1111/j.1461-0248.2009.01297.x. ISSN   1461-023X. PMID   19379136.
  22. 1 2 3 4 5 Slabbekoorn, Hans; Smith, Thomas B. (2000). "Does bill size polymorphism affect courtship song characteristics in the African finch Pyrenestes ostrinus?". Biological Journal of the Linnean Society. 71 (4): 737–753. doi: 10.1111/j.1095-8312.2000.tb01288.x . ISSN   0024-4066.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.