Sunbirds andspiderhunters make up thefamilyNectariniidae ofpasserine birds. They are small, slender passerines from theOld 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 are152 species in 16genera. Their family name is from most sunbirds feeding largely onnectar,[1] but they will also catchinsects andspiders, 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.[2]Fruit is also part of the diet of some species. Theirflight is fast and direct, thanks to their short wings.
The sunbirds have counterparts in two very distantly related groups: thehummingbirds of the Americas and thehoneyeaters of Australia. The resemblances are due toconvergent evolution brought about by a similar nectar-feeding lifestyle.[3] Some sunbird species can take nectar by hovering like a hummingbird, but they usually perch to feed.
The spectacled spiderhunter is the largest species of sunbird
The family ranges in size from the 5-gramblack-bellied sunbird to thespectacled spiderhunter, at about 45 grams. Like the hummingbirds, sunbirds are stronglysexually dimorphic, with the males usually brilliantly plumaged iniridescent colours.[4] 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.[5] Thespiderhunters, of the genusArachnothera, 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.[4]
In metabolic behaviour similar to that of Andes hummingbirds,[6] species of sunbirds that live at high altitudes or latitudes will entertorpor while roosting at night, lowering their body temperature and entering a state of low activity and responsiveness.[4][7]
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.[4]
Sunbirds are a tropicalOld World family, with representatives inAfrica,Asia andAustralasia. In Africa, they occur mostly insub-Saharan Africa andMadagascar and inEgypt. In Asia, the group occurs along the coast of theRed Sea to thePalestine region and along the Mediterranean up toBeirut, with a gap in their distribution across inland Syria and Iraq, and resuming inIran, from where the group occurs continuously as far as southernChina andIndonesia. In Australasia, they occur inNew Guinea, north easternAustralia and theSolomon Islands. They are generally not found on oceanic islands, with the exception of theSeychelles. The greatest variety of species is found in Africa, where the group probably arose. Most species are sedentary or short-distanceseasonal migrants. Sunbirds occur over the entire family's range, whereas the spiderhunters are restricted to Asia.[4]
The sunbirds and spiderhunters occupy a wide range of habitats, with a majority of species being found in primary rainforest, but other habitats used by the family including disturbed secondary forest, open woodland, open scrub and savannah, coastal scrub and alpine forest. Some species have readily adapted to human modified landscapes such as plantations, gardens and agricultural land. Many species are able to occupy a wide range of habitats from sea level to 4,900 m (16,100 ft).[4]
Sunbird are activediurnal birds that generally occur in pairs or occasionally in small family groups. A few species occasionally gather in larger groups, and sunbird will join with other birds tomob potential predators, although sunbirds will also aggressively target other species, even if they are not predators, when defending theirterritories.[4]
Sunbirds that breed outside of the equatorial regions are mostly seasonal breeders, with the majority of them breeding in thewet season. This timing reflects the increased availability of insect prey for the growing young. Where species, like thebuff-throated sunbird, breed in the dry season, it is thought to be associated with the flowering of favoured food plants. Species of sunbird in the equatorial areas breed throughout the year. They are generallymonogamous and often territorial, although a few species of sunbirds havelekking behaviour.[8]Thenests 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 thelittle spiderhunter, are small woven cups attached to the underside of large leaves; that of theyellow-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.[9] In the spiderhunters both sexes help to incubate the eggs.[9] The nests of sunbirds and spiderhunters are often targeted bybrood parasites such ascuckoos andhoneyguides.
Sunbird drinking nectar from typical bird-pollinated flower
As nectar is a primary food source for sunbirds, they are importantpollinators in African ecosystems. Sunbird-pollinated flowers are typically long, tubular, and red-to-orange in colour, showing convergent evolution with manyhummingbird-pollinated flowers in the Americas.[10] A key difference is that sunbirds cannot hover, so sunbird-pollinated flowers andinflorescences are typically sturdier than hummingbird-pollinated flowers, with an appropriate landing spot from which the bird can feed.[11][12] Sunbirds are critical pollinators for many iconic African plants, includingproteas,[13]aloes,[14]Erica,[12]Erythrina coral trees,[10] andbird-of-paradise flowers.[15] Specialization on sunbirds vs other pollinators is thought to have contributed to plantspeciation, including the exceptionally high floral diversity in southern Africa.[16][17]
Overall the family has fared better than many others, with only seven species considered to bethreatened withextinction. Most species are fairly resistant to changes in habitat, and while attractive 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 thescarlet-chested sunbird is considered a pest in cocoa plantations as it spreads parasiticmistletoes.[4]
^Prinzinger, R.; Schafer T.; Schuchmann K.L. (March 1992). "Energy metabolism, respiratory quotient and breathing parameters in two convergent small bird species : the fork-tailed sunbirdAethopyga christinae (Nectariniidae) and the Chilean HummingbirdSephanoides sephanoides (Trochilidae)".Journal of Thermal Biology.17 (2):71–79.Bibcode:1992JTBio..17...71P.doi:10.1016/0306-4565(92)90001-V.
^abcdefghCheke, Robert; Mann, Clive (2008). "Family Nectariniidae (Sunbirds)". In del Hoyo, Josep; Elliott, Andrew; Christie, David (eds.).Handbook of the Birds of the World, Volume 13: Penduline-tits to Shrikes. Barcelona: Lynx Editions. pp. 196–243.ISBN978-84-96553-45-3.
^Paton, D. C.; Collins, B. G. (1989). "Bills and tongues of nectar-feeding birds: A review of morphology, function and performance, with intercontinental comparisons".Australian Journal of Ecology.14 (4):473–506.doi:10.1111/j.1442-9993.1989.tb01457.x.ISSN1442-9993.
^Valente, Luis M.; Manning, John C.; Goldblatt, Peter; Vargas, Pablo (2012-07-01). "Did Pollination Shifts Drive Diversification in Southern African Gladiolus? Evaluating the Model of Pollinator-Driven Speciation".The American Naturalist.180 (1):83–98.doi:10.1086/666003.ISSN0003-0147.PMID22673653.S2CID5989519.
_Photograph_by_Shantanu_Kuveskar.jpg)
.jpg)
.jpg)
.jpg)
_male.jpg)
.jpg)
_female.jpg)
.jpg)
_(46533653022).jpg)
.jpg)
