Amethyst sunbird
{{Short description|Species of bird}}
{{Speciesbox
| image = Amethyst sunbird, Chalcomitra amethystina, male at Loodswaai, Gauteng, South Africa. - 50613935926, crop.jpg
| image2 = Amethyst sunbird, Chalcomitra amethystina, at Pilanesberg National Park, Northwest Province, South Africa (female) (17019732982), crop1.jpg
| image2_caption = Nominate male and female, South Africa
File:Amethyst Sunbird (Nectarinia amethystina) (W1CDR0000988 BD12).ogg, South Africa]]
| status = LC
| status_system = IUCN3.1
| genus = Chalcomitra
| species = amethystina
| authority = (Shaw, 1812)
| synonyms = Nectarinia amethystina
}}
The amethyst sunbird, also called the black sunbird (Chalcomitra amethystina), is a species of passerine bird in the family Nectariniidae. It is native to the Afrotropics, mostly south of the equator.{{cite web |title = Chalcomitra amethystina (Amethyst sunbird, Black sunbird) | url = http://www.biodiversityexplorer.org/birds/nectariniidae/chalcomitra_amethystina.htm |website=biodiversityexplorer.org |publisher=iziko museums |accessdate=15 October 2014}} They are commonly found in well-watered habitats, and undertake seasonal movements to visit flowering woodlands. The demise of some woodlands have impacted their numbers locally, but their range has also expanded along with the spread of wooded gardens.
Habits
Though mostly found singly or in pairs, larger numbers may concentrate at favourite flowering trees, where they act aggressively towards other sunbird species.{{cite book |last1=Zimmerman |first1=Dale A. |title=Birds of Kenya and Northern Tanzania |date=1996 |publisher=Russel Friedman Books |location=Halfway House |isbn=1-875091-04-1 |page=642|display-authors=etal}} The complex song is a loud, sustained twittering. Food includes emergent termites, spiders and nectar.{{cite web |title=Amethyst Sunbird (Chalcomitra amethystina) |url=http://www.hbw.com/species/amethyst-sunbird-chalcomitra-amethystina |website=hbw.com |publisher=Handbook of the Birds of the World|accessdate=15 October 2014}} In courtship a male will hop about a branch near a female, drop one wing, then the other, and finally both wings. The wings will then be fluttered and displayed. A responsive female may lower her head, and assume a rigid posture.{{cite journal |last1=Cowles |first1=Raymond B. |title=Observations on the Amethyst Sunbird, Chalcomitra amethystina amethystina (Shaw) |journal=The Auk |date=January 1936 |volume=53 |issue=1 |pages=28–30 |doi=10.2307/4077353 |jstor=4077353 |doi-access=free }}
Nesting
Breeding pairs of amethyst sunbird are widely spaced, and the female builds the nest.{{cite book |last1=Tarboton |first1=Warwick |title=Field guide to nests & eggs of Southern African birds |date=2000 |publisher=Struik |location=Cape Town |isbn=1-86872-271-6|pages=235–236}} Favoured trees include exotic eucalypts and pines, and are often close to buildings or human activity. Nests are attached to a drooping branch, below the canopy, or hidden by foliage. Nests are built from fine grass stems, which are bound together with cobwebs. The nest is often decorated with lichens, or other debris. Two speckled eggs are laid, but successive clutches may be raised from the same nest in a single season. Nests are parasitized by green-backed honeybird and Klaas's cuckoo.
Habitat and movements
Amethyst sunbirds are widespread residents of woodland, mesic savanna, forest edge and suburban gardens. They occur only sparsely in dry savanna{{cite book |last1=Irwin |first1=Michael P. Stuart |title=The birds of Zimbabwe |date=1981 |publisher=Quest Pub. |location=Salisbury, Zimbabwe |isbn=0-86925-156-2|pages=375–376}} or low dry regions, where they keep to riparian woods or concentrations of nectar-bearing plants, and are decidedly scarce in the Limpopo valley and mopane regions. A distinct summer influx is notable in the Zambezi valley and Great Zimbabwe woodlands, and they are strictly summer visitors (September/October to April) to the Kalahari sand (or Gusu) woodlands, where they appear in high densities when the Baikiaea trees are in flower. On seaward-facing slopes, they are very common residents up to 1,800 metres, with high reporting rates in afromontane forest and valley bushveld.{{cite book|last=Harisson |first=J.A. |title=The atlas of southern African birds |year=1997 |publisher=BirdLife SA |location=Johannesburg |isbn=0-620-20730-2 | url=http://sabap2.adu.org.za/docs/sabap1/792.pdf |pages=518–520|display-authors=etal}}
Adaptations
The average hematocrit level for birds is between 30 and 45%; however, the Amethyst Sunbird has an average hematocrit level of 50%.{{Cite journal|last=Marsen|first=Sky|date=2009-02-01|title=Book review: BARBARA JOHNSTONE, Discourse Analysis, 2nd edn. Oxford: Blackwell, 2008. 312 pp|url=https://journals.sagepub.com/doi/abs/10.1177/1461445608101544|journal=Discourse Studies|language=en|volume=11|issue=1|pages=121–123|doi=10.1177/1461445608101544|s2cid=143397992 |issn=1461-4456|url-access=subscription}} Amethyst sunbirds can be found along an altitudinal gradient in South Africa from the Drakensberg mountain range to the coast of KwaZulu-Natal.{{Cite journal|last=Yom-Tov|first=Yoram|date=2002-09-01|title=Sunbirds: A Guide to the Sunbirds, Flowerpeckers, Spiderhunters, and Sugarbirds of the World. By Robert A Cheke and Clive F Mann; illustrated by Richard Allen|url=https://www.journals.uchicago.edu/doi/10.1086/345222|journal=The Quarterly Review of Biology|volume=77|issue=3|pages=340–341|doi=10.1086/345222|issn=0033-5770|url-access=subscription}} During warmer months, the sunbird's hematocrit levels will increase with higher altitudes (where there is also a dramatic drop in temperature) and with lower oxygen concentrations in the atmosphere.{{Cite journal|last1=Lindsay|first1=Claire V.|last2=Downs|first2=Colleen T.|last3=Brown|first3=Mark|date=2010-10-01|title=Seasonal variation in hematocrit levels of Amethyst Sunbirds (Chalcomitra amethystina) over an altitudinal gradient|url=https://doi.org/10.1007/s10336-010-0522-z|journal=Journal of Ornithology|language=en|volume=151|issue=4|pages=851–855|doi=10.1007/s10336-010-0522-z|s2cid=37418670 |issn=1439-0361|url-access=subscription}} Higher hematocrit levels may be attributed to its small body size and can help with oxygen carrying capacity and the metabolic cost of flying.
Subpopulations of Amethyst Sunbirds show variation in their resting metabolic rates, basal metabolic rate, and thermal neutral zones based on the subpopulation's acclimation to different altitudes.{{Cite journal|last1=Lindsay|first1=Claire V.|last2=Downs|first2=Colleen T.|last3=Brown|first3=Mark|date=2009-02-15|title=Physiological variation in amethyst sunbirds (Chalcomitra amethystina) over an altitudinal gradient in winter|url=https://jeb.biologists.org/content/212/4/483|journal=Journal of Experimental Biology|language=en|volume=212|issue=4|pages=483–493|doi=10.1242/jeb.025262|issn=0022-0949|pmid=19181895|doi-access=free|url-access=subscription}} Those more acclimated to high altitudes would have lower metabolic rates and a larger thermal neutral zone. Therefore, the Amethyst Sunbird can change its physiology in response to altitude and temperature to achieve a metabolic rate and temperature regulation best suited for its environment.
Status
On the Mashonaland plateau, race kirkii has declined in favour of scarlet-chested sunbird, after fragmentation of its native miombo woodlands. In South Africa, the range of the nominate race has increased along with the spread of wooded gardens.
Range
It occurs in Angola, Botswana, Burundi, Republic of the Congo, Democratic Republic of the Congo, Eswatini, Ethiopia, Gabon, Kenya, Malawi, Mozambique, Namibia, Somalia, South Africa, South Sudan, Tanzania, Uganda, Zambia and Zimbabwe.
Races
Between three{{cite web|title=Amethyst Sunbird (Chalcomitra amethystina) |url=http://ibc.lynxeds.com/species/amethyst-sunbird-chalcomitra-amethystina |website=The Internet Bird Collection |publisher=IBC |accessdate=15 October 2014}} and eleven{{cite book |last1=Chittenden |first1=Hugh |last2=Allan |first2=David |last3=Weiersbye |first3=Ingrid (art) |title=Roberts geographic variation of southern African birds |date=2012 |publisher=John Voelcker Bird Book Fund |location=Cape Town |isbn=978-1-920602-00-0}} races have been proposed, including:
- C. a. amethystina
::Range: South Africa, southern Botswana, Eswatini
::Description: Fairly distinct: bill heavy, females dark from throat to belly, males have tail coverts metallic purple
- C. a. kirkii Shelley, 1876
::Range: Zimbabwe to East Africa
::Description: Bill finer than nominate, females much lighter on underside, males with dark brown (not purple) tail coverts
- C. a. kalckreuthi (Cabanis, 1878)
::Range: coastal Tanzania and Kenya
::Description: Bill slender, females pale below, unmarked on throat, supercilium long, males may have metallic purple upper tail coverts; often merged with C. a. kirkii
- C. a. deminuta Cabanis, 1880
::Range: West African tropics
- C. a. doggetti (Sharpe, 1902)
::Range: western Kenya
- C. a. adjuncta (Clancey, 1975)
::Range: Eswatini
::Description: Similar to nominate, with which it is often merged
Gallery
Image:Chalcomitra amethystina Keulemans.jpg|C. a. amethystina pair by J. G. Keulemans
Image:Chalcomitra amethystina kirkii Keulemans.jpg|C. a. kirkii pair by J. G. Keulemans
File:Amethyst_sunbird,_immature_male.jpg|Juvenile male of the nominate race
File:Amethyst sunbird, Chalcomitra amethystina, female at Kloofendal Nature Reserve, Johannesburg, South Africa (21354148246), crop.jpg|Juvenile male feeding on mistletoe nectar
File:Amethyst Sunbird specimen RWD.jpg|Female specimen, perhaps C. a. kirkii, Kenya
File:Chalcomitra amethystina (nom), nes, a, Seringveld.jpg|Female in nest suspended from low tree branch
References
{{Reflist}}
External links
{{commons category|Chalcomitra amethystina|Chalcomitra amethystina}}
- (Black Sunbird =) Amethyst Sunbird - [http://sabap2.adu.org.za/docs/sabap1/792.pdf Species text in The Atlas of Southern African Birds].
{{Taxonbar|from=Q1923701}}
Category:Birds of Sub-Saharan Africa