Sunbirds and spiderhunters make up the family Nectariniidae of passerine birds. They are small, slender passerines from the Old World, usually with downward-curved bills. Many are brightly coloured, often with iridescent feathers, particularly in the males. Many species also have especially long tail feathers. Their range extends through most of Africa to the Middle East, South Asia, South-east Asia and southern China, to Indonesia, New Guinea and northern Australia. Species diversity is highest in equatorial regions.

There are 152 species in 16 genera. Their family name is from most sunbirds feeding largely on nectar, but they will also catch insects and spiders, especially when feeding their young. Flowers that prevent access to their nectar because of their shape (for example, very long and narrow flowers) are simply punctured at the base near the nectaries, from which the birds sip the nectar. Fruit is also part of the diet of some species. Their flight is fast and direct, thanks to their short wings.

The sunbirds have counterparts in two very distantly related groups: the hummingbirds of the Americas and the honeyeaters of Australia. The resemblances are due to convergent evolution brought about by a similar nectar-feeding lifestyle. Some sunbird species can take nectar by hovering like a hummingbird, but they usually perch to feed.

Description

thumb|left|The spectacled spiderhunter is the largest species of sunbirdThe family ranges in size from the 5-gram black-bellied sunbird to the spectacled spiderhunter, at about 45 grams. Like the hummingbirds, sunbirds are strongly sexually dimorphic, with the males usually brilliantly plumaged in iridescent colours. In addition to this the tails of many species are longer in the males, and overall the males are larger. Sunbirds have long thin down-curved bills and brush-tipped tubular tongues, both adaptations to their nectar feeding. The spiderhunters, of the genus Arachnothera, are distinct in appearance from the other members of the family. They are typically larger than the other sunbirds, with drab brown plumage that is the same for both sexes, and long, down-curved beaks. species of sunbirds that live at high altitudes or latitudes will enter torpor while roosting at night, lowering their body temperature and entering a state of low activity and responsiveness.

The moulting regimes of sunbirds are complex, being different in different species. Many species have no eclipse plumage but do have juvenile plumage. Some species do show duller plumage in the off-season. In the dry months of June−August, male copper sunbirds and variable sunbirds lose much of their metallic sheen. In some instances, different populations of the same species can display variation in different molting regimes.

The nests of sunbirds are generally purse-shaped, enclosed, suspended from thin branches with generous use of spiderweb. The nests of the spiderhunters are different, both from the sunbirds and in some cases from each other. Some, like the little spiderhunter, are small woven cups attached to the underside of large leaves; that of the yellow-eared spiderhunter is similarly attached but is a long tube. The nests of spiderhunters are inconspicuous, in contrast to those of the other sunbirds which are more visible. In most species the female alone constructs the nest. Up to four eggs are laid. The female builds the nest and incubates the eggs alone, although the male assists in rearing the nestlings. In the spiderhunters both sexes help to incubate the eggs. A key difference is that sunbirds cannot hover, so sunbird-pollinated flowers and inflorescences are typically sturdier than hummingbird-pollinated flowers, with an appropriate landing spot from which the bird can feed. Sunbirds are critical pollinators for many iconic African plants, including proteas, aloes, Erica, Specialization on sunbirds vs other pollinators is thought to have contributed to plant speciation, including the exceptionally high floral diversity in southern Africa.

Relationship with humans

Seven species are considered to be threatened with extinction. Most species are fairly resistant to changes in habitat, and the family is not sought after by the cagebird trade as they have what is considered an unpleasant song and are tricky to keep alive. Sunbirds are considered attractive birds and readily enter gardens where flowering plants are planted to attract them. There are a few negative interactions, for example the scarlet-chested sunbird is considered a pest in cocoa plantations as it spreads parasitic mistletoes. For more detail, see list of sunbird species.

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! Image !! Genus !! Species

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|150px

||Chalcoparia ||

  • Chalcoparia singalensis (monotypic) – ruby-cheeked sunbird

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| 150px

||Deleornis ||

  • Fraser's sunbird, Deleornis fraseri
  • Grey-headed sunbird, Deleornis axillaris

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|150px ||Anthreptes ||

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|150px ||Hedydipna ||

  • Collared sunbird, Hedydipna collaris
  • Pygmy sunbird, Hedydipna platura
  • Nile Valley sunbird, Hedydipna metallica
  • Amani sunbird, Hedydipna pallidigaster

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|150px ||Anabathmis ||

  • Reichenbach's sunbird, Anabathmis reichenbachii
  • Príncipe sunbird, Anabathmis hartlaubii
  • Newton's sunbird, Anabathmis newtonii

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|150px

||Dreptes ||

  • Dreptes thomensis (monotypic) – giant sunbird

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|150px ||Anthobaphes ||

  • Anthobaphes violacea (monotypic) – orange-breasted sunbird

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|150px ||Cyanomitra ||

  • Green-headed sunbird, Cyanomitra verticalis
  • Bannerman's sunbird, Cyanomitra bannermani
  • Blue-throated brown sunbird, Cyanomitra cyanolaema
  • Cameroon sunbird, Cyanomitra oritis
  • Blue-headed sunbird, Cyanomitra alinae
  • Olive sunbird, Cyanomitra olivacea
  • Grey sunbird, Cyanomitra veroxii

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|150px ||Chalcomitra ||

  • Buff-throated sunbird, Chalcomitra adelberti
  • Carmelite sunbird, Chalcomitra fuliginosa
  • Green-throated sunbird, Chalcomitra rubescens
  • Amethyst sunbird, Chalcomitra amethystina
  • Scarlet-chested sunbird, Chalcomitra senegalensis
  • Hunter's sunbird, Chalcomitra hunteri
  • Socotra sunbird, Chalcomitra balfouri

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|150px ||Leptocoma ||

  • Purple-rumped sunbird, Leptocoma zeylonica
  • Crimson-backed sunbird, Leptocoma minima
  • Purple-throated sunbird, Leptocoma sperata
  • Van Hasselt's sunbird, Leptocoma brasiliana
  • Black sunbird, Leptocoma aspasia
  • Copper-throated sunbird, Leptocoma calcostetha

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|150px ||Nectarinia ||

  • Bocage's sunbird, Nectarinia bocagii
  • Purple-breasted sunbird, Nectarinia purpureiventris
  • Tacazze sunbird, Nectarinia tacazze
  • Bronze sunbird, Nectarinia kilimensis
  • Malachite sunbird, Nectarinia famosa
  • Scarlet-tufted sunbird, Nectarinia johnstoni

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|150px ||Drepanorhynchus ||

  • Drepanorhynchus reichenowi (monotypic) – golden-winged sunbird

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|150px ||Cinnyris ||

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|150px ||Aethopyga ||

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|150px ||Kurochkinegramma ||

  • Kurochkinegramma hypogrammicum (monotypic) – purple-naped spiderhunter

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|150px ||Arachnothera ||

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References

  • Sunbird videos on the Internet Bird Collection