Sunbirds and spiderhunters | |
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Male Vigors's sunbird from Maharashtra, India | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Chordata |
Class: | Aves |
Order: | Passeriformes |
Superfamily: | Passeroidea |
Family: | Nectariniidae Vigors, 1825 |
Genera | |
16, see text |
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 151 species in 16 genera. Their family name is from most sunbirds feeding largely on nectar, [1] 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. [2] 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. [3] Some sunbird species can take nectar by hovering like a hummingbird, but they usually perch to feed.
The 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. [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] 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. [4]
In metabolic behaviour similar to that of Andes hummingbirds, [6] 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. [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 tropical Old World family, with representatives in Africa, Asia and Australasia. In Africa they are found mostly in sub-Saharan Africa and Madagascar but are also distributed in Egypt. In Asia the group occurs along the coasts of the Red Sea as far north as Israel, and along the Mediterranean as far north as Beirut, with a gap in their distribution across inland Syria and Iraq, and resuming in Iran, from where the group occurs continuously as far as southern China and Indonesia. In Australasia the family occurs in New Guinea, north eastern Australia and the Solomon Islands. They are generally not found on oceanic islands, with the exception of the Seychelles. The greatest variety of species is found in Africa, where the group probably arose. Most species are sedentary or short-distance seasonal 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 4900 m. [4]
Sunbird are active diurnal 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 to mob potential predators, although sunbirds will also aggressively target other species, even if they are not predators, when defending their territories. [4]
Sunbirds that breed outside of the equatorial regions are mostly seasonal breeders, with the majority of them breeding in the wet season. This timing reflects the increased availability of insect prey for the growing young. Where species, like the buff-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 generally monogamous and often territorial, although a few species of sunbirds have lekking behaviour. [8] 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. [9] In the spiderhunters both sexes help to incubate the eggs. [9] The nests of sunbirds and spiderhunters are often targeted by brood parasites such as cuckoos and honeyguides.
As nectar is a primary food source for sunbirds, they are important pollinators in African ecosystems. Sunbird-pollinated flowers are typically long, tubular, and red-to-orange in colour, showing convergent evolution with many hummingbird-pollinated flowers in the Americas. [10] 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. [11] [12] Sunbirds are critical pollinators for many iconic African plants, including proteas, [13] aloes, [14] Erica , [12] Erythrina coral trees, [10] and bird-of-paradise flowers. [15] Specialization on sunbirds vs other pollinators is thought to have contributed to plant speciation, 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 be threatened with extinction. 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 the scarlet-chested sunbird is considered a pest in cocoa plantations as it spreads parasitic mistletoes. [4]
The family contains 151 species divided into 16 genera: [18] For more detail, see list of sunbird species.
Image | Genus | Species |
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Chalcoparia Cabanis, 1851 |
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Deleornis Wolters, 1977 |
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Anthreptes Swainson, 1832 | 15 species:
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Hedydipna Cabanis, 1851 |
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Anabathmis Reichenow, 1905 |
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Dreptes Illiger, 1811 |
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Anthobaphes Cabanis, 1851 |
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Cyanomitra Reichenbach, 1853 |
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Chalcomitra Reichenbach, 1853 |
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Leptocoma Cabanis, 1851 |
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Nectarinia Illiger, 1811 |
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Drepanorhynchus Fischer & Reichenow, 1884 |
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Cinnyris Cuvier, 1816 | 63 species:
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Aethopyga Cabanis, 1851 | 22 species:
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Kurochkinegramma Kashain, 1978 |
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Arachnothera Temminck, 1826 | 13 species:
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Hummingbirds are birds native to the Americas and comprise the biological family Trochilidae. With approximately 366 species and 113 genera, they occur from Alaska to Tierra del Fuego, but most species are found in Central and South America. As of 2024, 21 hummingbird species are listed as endangered or critically endangered, with numerous species declining in population.
Heliconia is a genus of flowering plants in the monotypic family Heliconiaceae. Most of the 194 known species are native to the tropical Americas, but a few are indigenous to certain islands of the western Pacific and Maluku in Indonesia. Many species of Heliconia are found in the tropical forests of these regions. Most species are listed as either vulnerable or data deficient by the IUCN Red List of threatened species. Several species are widely cultivated as ornamentals, and a few are naturalized in Florida, Gambia, and Thailand.
The collared sunbird is a bird species of the family Nectariniidae. The sunbirds are a group of very small Old World passerine birds which feed largely on nectar, although they will also take insects, especially when feeding young. The collared sunbird is in fact mainly insectivorous.
The spiderhunters are birds of the genus Arachnothera, part of the sunbird family Nectariniidae. The genus contains thirteen species found in the forests of south and southeastern Asia. They are large representatives of the sunbird family, with drab plumage and long strongly curved bills. They feed on both nectar and a range of small arthropods.
The purple sunbird is a small bird in the sunbird family. It occurs in parts of the Arabian peninsula and South and Southeast Asia. It has a fast and direct flight and can take nectar by hovering like a hummingbird but often perches at the base of flowers. It feeds mainly on nectar and insects, especially when feeding young. The males can appear all black in harsh sunlight but the purple iridescence is visible on closer observation or under good light conditions. Females are olive above and yellowish below.
Parallel evolution is the similar development of a trait in distinct species that are not closely related, but share a similar original trait in response to similar evolutionary pressure.
Zoophily, or zoogamy, is a form of pollination whereby pollen is transferred by animals, usually by invertebrates but in some cases vertebrates, particularly birds and bats, but also by other animals. Zoophilous species frequently have evolved mechanisms to make themselves more appealing to the particular type of pollinator, e.g. brightly colored or scented flowers, nectar, and appealing shapes and patterns. These plant-animal relationships are often mutually beneficial because of the food source provided in exchange for pollination.
Nectar is a viscous, sugar-rich liquid produced by plants in glands called nectaries, either within the flowers with which it attracts pollinating animals, or by extrafloral nectaries, which provide a nutrient source to animal mutualists, which in turn provide herbivore protection. Common nectar-consuming pollinators include mosquitoes, hoverflies, wasps, bees, butterflies and moths, hummingbirds, honeyeaters and bats. Nectar plays a crucial role in the foraging economics and evolution of nectar-eating species; for example, nectar foraging behavior is largely responsible for the divergent evolution of the African honey bee, A. m. scutellata and the western honey bee.
In zoology, a nectarivore is an animal which derives its energy and nutrient requirements from a diet consisting mainly or exclusively of the sugar-rich nectar produced by flowering plants.
Ornithophily or bird pollination is the pollination of flowering plants by birds. This sometimes coevolutionary association is derived from insect pollination (entomophily) and is particularly well developed in some parts of the world, especially in the tropics, Southern Africa, and on some island chains. The association involves several distinctive plant adaptations forming a "pollination syndrome". The plants typically have colourful, often red, flowers with long tubular structures holding ample nectar and orientations of the stamen and stigma that ensure contact with the pollinator. Birds involved in ornithophily tend to be specialist nectarivores with brushy tongues and long bills, that are either capable of hovering flight or light enough to perch on the flower structures.
Pollination syndromes are suites of flower traits that have evolved in response to natural selection imposed by different pollen vectors, which can be abiotic or biotic, such as birds, bees, flies, and so forth through a process called pollinator-mediated selection. These traits include flower shape, size, colour, odour, reward type and amount, nectar composition, timing of flowering, etc. For example, tubular red flowers with copious nectar often attract birds; foul smelling flowers attract carrion flies or beetles, etc.
The orange-breasted sunbird is a species of small, predominantly nectar-feeding bird that is endemic to the fynbos shrubland biome of southwestern South Africa. It is the only member of the genus Anthobaphes, in the family Nectariniidae, though it is sometimes placed in the genus Nectarinia. The birds are sexually dimorphic, with females being olive green while the males are orange to yellow on the underside with bright green, blue and purple on the head and neck.
The malachite sunbird is a small nectarivorous bird found from the highlands of Ethiopia southwards to South Africa. They pollinate many flowering plants, particularly those with long corolla tubes, in the Fynbos.
Whitehead's spiderhunter is a species of spiderhunter in the sunbird and spiderhunter family Nectariniidae. It is endemic to Borneo, where it is found in the mountain ranges in the north-central part of the island. It inhabits hill dipterocarp forest, primary and secondary montane forest, and forest edge at elevations of 930–3,000 m (3,050–9,840 ft). A large and distinctive spiderhunter, the species is mostly brown with profuse whitish streaking all over the body and bright yellow vents and uppertail coverts. Both sexes are similar in appearance, but males are larger, with a length of 16.5–18 cm (6.5–7.1 in) compared to a length of 15.5–16.5 cm (6.1–6.5 in) for females. The juvenile plumage is unknown.
The little spiderhunter is a species of long-billed nectar-feeding bird in the family Nectariniidae found in the moist forests of South and Southeast Asia. Unlike typical sunbirds, males and females are very similar in plumage. They are usually seen in ones or twos and frequently make a tzeck call. They are most often found near flowering plants where they obtain nectar.
The copper-throated sunbird is a small passerine within the Nectariniidae family. They sustain themselves by consuming nectar as well as small invertebrates. As a member of the Nectariniidae family, they possess downward curved beaks and have pectoral tufts of yellow feathers. They are found in south-eastern Asia, predominantly in coastal regions.
The olive-bellied sunbird is a species of bird in the family Nectariniidae. It is widely spread across the African tropical rainforest.
The scarlet-tufted sunbird is a species of bird in the Nectarinia of the family Nectariniidae. It is found in Democratic Republic of the Congo, Kenya, Malawi, Rwanda, Tanzania, Uganda, and Zambia. It is also known as the red-tufted sunbird and the scarlet-tufted malachite sunbird.
The black-bellied sunbird(Cinnyris nectarinioides) is a small sunbird located primarily in Africa. Two subspecies are recognized: the Cinnyris nectarinioides erlangeri, which is smaller and found in Ethiopia, Somalia, and Kenya; and the Cinnyris nectarinioides nectarinioides, which is larger and found in Kenya and Tanzania. This bird inhabits savannah, wetlands, and terrestrial freshwater areas.
The golden-winged sunbird is a species of bird in the family Nectariniidae. Three subspecies are recognised. It is native to the Albertine Rift montane forests and East African montane forests.