Old World Orioles and Figbirds (Oriolidae)

views updated

Old World orioles and figbirds

(Oriolidae)

Class Aves

Order Passeriformes

Suborder Passeri (Oscines)

Family Oriolidae

Thumbnail description
Orioles and figbirds are tree-living song-birds commonly patterned in brilliant yellows and blacks, and streaked ventrally in juveniles and some adults.

Size
7–11.5 in (20–28 cm); 2–5 oz (50–135 g)

Number of genera, species
2 genera; 29-30 species

Habitat
Medium to tall woodland and forest, including rainforest

Conservation status
Endangered: 1 species; Vulnerable: 2 species; Near Threatened: 3 species

Distribution
Sub-Saharan and far northwest Africa, temperate Eurasia (except central deserts), south and east to India, southeast Asia, and Indonesian archipelagos as far as New Guinea, and north and east Australia

Evolution and systematics

Among songbirds, orioles and figbirds are so typical in appearance and behavior that their origins and relationships have excited little interest. But molecular evidence shows that they are closely allied to Old World cuckoo-shrikes (Campephagidae) and other crow-like songbirds, not starlings (Sturnidae) as traditionally held. Like cuckoo-shrikes, orioles and figbirds are outlying members of a massive evolutionary explosion in crow-like songbirds that originated in Australia in early- to mid-Teriary times, more than 30 million years ago, and then spread north and west through the tropical and temperate Old World. Whether today's orioles and figbirds actually arose in Australasia, or diversified outside to re-enter Australia later within the last few million years, is still in dispute.

Oriolidae comprises three species of figbirds (Sphecotheres) and 26-27 of orioles (Oriolus). The three figbirds replace one another geographically in different parts of tropical Indo-Australasia east of Wallace's Line. The orioles comprise four, perhaps five, species-groups: golden-headed orioles, a widespread migratory group of four species in west and east Eurasia, India, and central Africa; a black-headed group of seven resident species in Africa, and the black-hooded oriole (O. xanthornus) in east Asia; the four sedentary dusky orioles of Southeast Asia and adjacent archipelagos; and the streaked, juvenal-plumaged Australasian orioles, with seven species. The three or four remaining oriole species, all Southeast Asian, are of uncertain affinity.

Physical characteristics

Orioles and figbirds are thrush-like in shape and size, with wings that are long yet rounded, and a square-tipped, 12-feathered tail. The tenth primary flight feather is well developed, while the number of secondary feathers is usually 11 in orioles and only 10 in figbirds. Bills are straight, stout, and notched at the tip of the upper mandible, fitted for grasping and pulling at food; bristles flanking the bill are vestigial and nostrils are narrow slits partially protected by a membrane. Adapted for perching, feet are stout, and the tarsus (leg) coarsely scaled and shorter than the longest toe.

Spectacular yellows and blacks are the badge of oriole plumage; vermillion eyes, brick-red bills, and slate-gray feet complete the picture. Only figbirds and dusky Asian orioles have black or slate-colored bills, sometimes pale eyes, and flesh-colored or black feet. Male orioles are invariably more brightly plumaged that females; juveniles have brown-olive backs with dull bills, eyes, and feet, and are white ventrally with dusky streaks. In the golden-headed group, adult males are almost wholly golden-yellow except for black wings, center tail, and a black mark through the eye, while females are plumaged like dull males or bright juveniles. In black-headed orioles, both males and females have yellow bodies, often gray wings, and black or dark olive heads; in the dusky group, males have dusky or silver bodies with splashes of deep red on the undersurface and tail, and females are browner and sometimes streaked on the belly. In the Indo-Australian streaked group,

both sexes are dull brown or olive-yellow with varied ventral streaking, as in juveniles. Adult plumage is gained at one to three years of age. Male figbirds have black crowns and bills, olive backs, and yellow, white, olive, or gray breasts, while females and juveniles are plumaged like juvenile orioles. Apart from bulk and a broad head, the only other outward difference in figbirds is a patch of bare skin around the eye, which is enlarged and warty in males, and reddens with pumped blood in excitement, indicating a signal function.

Distribution

The tropics and temperate regions of the Old World east to Australia are the home of orioles and figbirds today. Only two orioles occur in the north temperate region, one in the west, including Europe, and the other in the east, including Japan; both are migratory. To the south, there are three centers of diversity: sub-Saharan Africa, which holds nine species (seven resident black-headed and two golden-headed orioles, one a non-breeding migrant); Southeast Asia south of the Himalayas and central China, west to peninsular India and Sri Lanka, and east to the Greater Sundas and Philippines, which has up to 12 species in three or four species groups, all resident endemics except for two migrant golden-headed orioles; and east and north Australia-New Guinea west to the Moluccas and Lesser Sundas, where the figbirds and streaked orioles are endemic.

Habitat

Living almost exclusively in the crowns of trees, orioles and figbirds are found in rather open broadleaf forests and woodlands in temperate regions, but also in rainforests in the tropics. Most migratory species forage through a range of forest and woodland types, while sedentary species occupy narrower niches. Densities when breeding range from about two to 10 pairs per 0.6 sq mi (1 sq km), depending on habitat productivity and connectivity.

Behavior

Orioles are usually solitary and secretive, while figbirds are communal and extrovert. Figbirds often perch conspicuously on high bare branches in loose flocks of up to 30 or more, giving their simple one- or two-note whistled songs year-round to maintain contact. In contrast, orioles sing a short rolling glottal warble that is repeated monotonously during breeding and carries for almost half a mile (500 m) to advertise territory. The grouping and pitch of the notes may vary among species, but its character remains much the same everywhere. In agitation, both orioles and figbirds utter short, harsh squawks. Flight is direct and undulating, from tree to tree; it is swifter in orioles and ends in a flashing up-swoop on to a perch. Within tree crowns, orioles and figbirds are quiet and measured in their movements, perching still, or hopping about in search of food. They sun-bathe and rain-bathe there, but will also go to ground to water and infrequently feed, drinking mainly by "pumping" (sucking).

Feeding ecology and diet

Orioles eat small, soft fruit and insects opportunistically, whereas figbirds are more strictly frugivorus. By quartering

tracts of forest in groups, figbirds converge on trees and work them over for the last ripe fruit; small fruits are swallowed whole. Often more territorial in their foraging, orioles take the same range of small fruits, but include hairy caterpillars and many other insects in their diet. They beat the larger insects vigorously against a perch to clean and soften them. It has been claimed that, for their protection when feeding and breeding, the streaked Indo-Australasian orioles have come to mimic other more aggressive birds in their appearance. Yet such mimicry may exist only in the eye of the human beholder, given that birds see color in a different way than humans.

Reproductive biology

Breeding occurs erratically year-round in the tropics but is confined to spring and early summer in temperate regions. Orioles and figbirds are essentially monogamous. Oriole males establish and hold territory while females build the nest and incubate with minimal help. Orioles build thick, deep basket-shaped nests of dry plant fiber bound with animal wool, moss, and lichen, which they sling in a horizontal fork in the outer branches of trees, usually well above the ground. Foundation strips are glued with saliva to hold the nest. Figbirds, in contrast, build a transparently flimsy cup of twigs and tendrils in small outer branches. Eggs, two to four per clutch, are pink white to pale cream-buff in orioles or pale gray olive in figbirds, and sparingly spotted and speckled with black to red-browns. They hatch in 16–18 days. Young have yellow down and are fed by regurgitation by both parents, and occasional male helpers; they fledge in equivalent time. The brood, usually just one a year, is dispersed almost as soon as the fledglings become independent.

Conservation status

Only the Isabela oriole (O. isabellae) on isolated mountains in the northern Philippines is considered Endangered. Its habitat is threatened by clearing and logging, even in reserves. There are two Vulnerable species: the silver oriole (O. mellianus), which breeds locally in south-central China, and winters south to Thailand and Cambodia, and the Sao Tome oriole (O. crassirostris) of remnant primary forests on Sao Tome Island, tropical West Africa. Habitat disruption and, for the latter, pesticides are thought to have contributed to decline. Three species are Near Threatened: the black oriole (O. hosii) of montane northeast Borneo, the dark-throated oriole (O. xanthonotus) of Southeast Asia, and the Wetar figbird (Sphecotheres hypoleucus), which is endemic to Wetar in the Lesser Sundas.

Significance to humans

Despite their color, orioles and figbirds have made little impression on human society. The Eurasian golden oriole (O. oriolus) is a harbinger of impending summer in Europe and has sometimes been brought into captivity there, as have other species in Africa and Southeast Asia. No serious attempts have been made at introduction or acclimatization.

Species accounts

List of Species

Australasian figbird
Timor figbird
Olive-backed oriole
Crimson-bellied oriole
Eastern black-headed oriole
Eurasian golden oriole

Australasian figbird

Sphecotheres vieilloti

taxonomy

Sphecotheres vieilloti Vigors & Horsfield, 1827, Keppel Bay, Queensland, Australia. Four subspecies: two (flaviventris, ashbyi) with yellow-ventrumed males in northern Australia and the Kai Islands, differing in tone of back; one (salvadorii) with gray-, yellow-, and white-ventrumed males in southeast New Guinea, and one (vieilloti) with gray- and olive-ventrumed males in central east Australia. Taxonomy controversial.

other common names

English: Green figbird, southern figbird; French: Sphécothère de Vieillot. German: Feigenpirol; Spanish: Papahigos Verde.

physical characteristics

10–11.5 in (25–29 cm); 4–4.5 oz (110–130 gm), both sexes. A stout, shortish-tailed figbird; upperparts olive-green, except black on head, primaries, and tail. Throat is gray with buff-red bare eye skin.

distribution

Coastal northern and eastern Australia (Kimberley Division to Illawarra district), southeast New Guinea, and Kai Islands (Banda Sea).

habitat

Rainforest edge, gallery vine forest, mangroves, and adjacent gardens.

behavior

Communal, in noisy, loose, locally nomadic flocks of up to 30–50 in tree canopy; often perches high on bare branches and power lines to group and call: loud, single- or double-note whistles.

feeding ecology and diet

Feeds in tree crowns primarily on small, soft fruit such as figs and native cherries; ink weed and tobacco bush are staple diet; bananas, guavas, and mulberries are occasionally taken in orchards.

reproductive biology

Monogamous in small groups, holding small territories during later austral spring and summer (October–February). Nests are shallow, flimsy, and saucer-like, built of plant fiber and tendrils. Eggs usually three. Both parents share all nesting duties, and additional birds may help feed the young.

conservation status

No populations are under threat anywhere, having adapted to habitats subject to disturbance and regeneration.

significance to humans

None known, apart from occasional nuisance value to fruit growers.

Timor figbird

Sphecotheres viridis

taxonomy

Specoterasic viridis Vieillot, 1816, Australasia = Kupang, Timor.

other common names

English: Green figbird; French: Sphécothère figuier; German: Feigenpirol; Spanish: Papahigos de Timor.

physical characteristics

8.7–9.5 in (22–24 cm); 2.4–2.8 oz (75–80 gm), both sexes. A small, slender figbird; males are plain olive ventrally, with gray throat, undertail, and feet. Dark head with rough bare eyeskin colored deep buff but changing to red when excited. Throat to vent greenish yellow.

distribution

Endemic to Timor.

habitat

Primary and secondary vine and gallery forest, forest edge, woodland, and mangroves.

behavior

Solitary to communal, feeding locally through tree crowns in small loose flocks. Calls from exposed position in tree tops: muted, burred, metallic whistled trills.

feeding ecology and diet

Little recorded; observed feeding on small, soft fruit in trees, including figs.

reproductive biology

Not known.

conservation status

Widespread and moderately abundant; copes with habitats affected by disturbance.

significance to humans

None known.

Olive-backed oriole

Oriolus sagittatus

taxonomy

Coracias sagittata Latham, 1802, "Nova Wallia Australi" = central coast, New South Wales, Australia.

other common names

English: Green oriole, white-bellied oriole; French: Loriot sagittal; German: Streifenpirol; Spanish: Oropéndola de Lomo Olivo.

physical characteristics

10.2–11 in (26–28 cm); 3.5–3.8 oz (90–105 gm), both sexes. Plain olive upperparts; wings and tail dark gray with white edging. Whitish underparts with dark steaks. Eyes red.

distribution

Coastal and subcoastal northern and eastern Australia up to about 500 mi (800 km) inland, between Kimberley Division and Victoria, also dry south New Guinea.

habitat

Open eucalypt forest and tall woodland; also paperbark (Melaleuca) woodland in north Australia and New Guinea.

behavior

Solitary in forest/woodland canopy, pairing only to breed. Gives low carrying glottal warble from set perches throughout year, and incessantly, with mimicry, when breeding. Widely nomadic after breeding.

feeding ecology and diet

Forages opportunistically on small soft fruits in trees and tall shrubs and on insects such as leaf beetles, mantids, ants, and caterpillars; mostly captures prey while quietly hopping and gleaning upper and outer branches of trees.

reproductive biology

Monogamous; female builds nest (about 14 days) and incubates (17–18 days), but both sexes feed young, fledging them in 15–27 days.

conservation status

No populations under significant threat anywhere.

significance to humans

None known.

Crimson-bellied oriole

Oriolus cruentus

taxonomy

Leptopteryx cruenta Wagler, 1827, Java. Four subspecies, one each in four regions of accurrence.

other common names

English: Black-and-crimson oriole; French: Loriot ensanglanté; German: Rotbrustpirol; Spanish: Oropéndola de Pecho Rojo.

physical characteristics

8.5–9 in (21.5–23 cm); no weights available. A dusky, gray-billed oriole with crimson or chestnut lower breast and belly and mark in wing.

distribution

Greater Sunda Land: Malay Peninsula, Sumatra, Java, and north Borneo.

habitat

Closed, primarily high montane rainforests above 3,300 ft (1,000 m).

behavior

Retiring and sedentary, working locally through the inner forest canopy and forest midstage singly or in pairs, although foraging out into cloud forest at high altitudes. Song is a short, mewing, nasal warble of about four syllables, repeated at intervals.

feeding ecology and diet

Little known, though hops about actively when foraging and often descends to logs in forest substage. Eats small soft fruits such as figs and berries, and takes a wide range of insects including termites, diverse larvae, and particularly caterpillars, both hairless and haired.

reproductive biology

Insufficiently known.

conservation status

None of the four mountain island populations appear to be under threat at present, although accelerating habitat destruction could impact them in the future.

significance to humans

None known.

Eastern black-headed oriole

Oriolus larvatus

taxonomy

Oriolus larvatus Lichtenstein, 1823, "Terr. Caffror" = Cape Province, South Africa. Five or six regional subspecies differing in size and tone of golden plumage.

other common names

English: Black-headed oriole, African black-headed oriole; French: Loriot à tête noire oriental; German: Maskenpirol; Spanish: Oropéndola de Cabeza Negra Africana.

physical characteristics

8–8.5 in (20–21.5 cm); 2.2–2.5 oz (60–70 gm). Sexes similar. A black-headed oriole with citrine back, golden ventrum, and gray-green wings and tail; only immatures duller and streaked ventrally.

distribution

Central and southeastern Africa, north to Sudan and southwest Ethiopia, south to Cape Province, and west through much of Angola locally to west coast.

habitat

Acacia and broad-leaved woodlands, especially in galleries along streams; also thorn scrub, forest edge, tree plantations, and gardens.

behavior

Solitary and rather sedentary, in pairs or small family groups only when breeding or at food concentrations. Calls in considerable variety from tree perches throughout year, mimicking and giving both fluted glottal warbles and figbird-like whistles.

feeding ecology and diet

Forages mainly in tree crowns, hopping and fluttering, for fruits and caterpillars. Food comprises both small, soft native fruits such as figs, grapes, and mulberries, and insects, particularly large haired and hairless caterpillars, all taken opportunistically.

reproductive biology

Monogamous and territorial, pairs holding territories of 12–120 acres (5–50 ha). Breeds erratically year-round in tropics, but limited to spring and summer in temperate southern latitudes. Female builds nest and broods, and male holds territory and assists in rearing young. Nests slung in a three-way fork in horizontal branches at 15–50 ft (5–15 m) above the ground. Eggs in clutches of one to two in tropics and two to three in temperate zone, hatch in 14–15 days; young fledge in another 15–18.

conservation status

No forms of this common and widespread species are under threat.

significance to humans

None known.

Eurasian golden oriole

Oriolus oriolus

taxonomy

Oriolus oriolus Linnaeus, 1758, "in Europe, Asia" = Sweden. Two subspecies, one in Europe to west Asia and the other in Central Asia, differing in size, proportions, and black stripe through eye.

other common names

English: Golden oriole, oriole; French: Loriot d'Europe; German: Pirol; Spanish: Oropéndola Europea.

physical characteristics

8.3–9.5 in (21–24 cm); 2–2.8 oz (55–80 gm), both sexes. An all-golden oriole with black wings, tail, and stripe through eye; female duller and greenish-backed.

distribution

Europe and far northwest Africa east to Asia Minor, the Caspian Sea, western Siberia, and, in winter, sub-Saharan Africa; Central Asia, from western Siberia south in winter to Afghanistan and Himalayas, peninsular India, and north Sri Lanka.

habitat

Woodlands and open forests of primarily broadleaf and deciduous mature trees, including parkland.

behavior

Solitary and retiring, keeping within the upper stages of large trees. Song, given year-round by both sexes but more by males during breeding, is a loud, liquid, warbled whistle of three or four syllables, repeated; a grating, drawn-out squalling given in agitation, as well as a range of warbled sub-songs.

feeding ecology and diet

Forages by picking mainly in foliage of tree crowns, but also occasionally by hovering and perch-pouncing near to ground. Diet includes both a range of insects, including hairy caterpillars, and a range of small fruits, as well as some seeds, buds, small reptiles, nestling birds, and eggs.

reproductive biology

Monogamous, single-brooded, and territorial, males holding dispersed territories. Nest, a shallow cup of plant fiber and stems slung from a thin horizontal fork in high foliage, is built in 6–12 days by female, with initial assistance from male. Eggs, three to four per clutch, are creamy or pink-white with scattered dark brown and blackish spots. Incubated by female with assistance from male, they hatch in 15–18 days. Young, fed by both parents and infrequent trios, fledge in 16–20 days.

conservation status

Neither subspecies appears to be under threat at present, though status of central Asian race unclear. For western subspecies, declines in central and eastern Europe over past 50 years partly offset by increases in western Europe.

significance to humans

A noted harbinger of spring and summer in northern Europe, both for its golden plumage and fluted song. Occasionally brought into aviculture in Europe as well.

Resources

Books

Cramp, S., and C. M. Perrins, eds. "Flycatchers to Shrikes." The Birds of the Western Palearctic, Vol. VII. Oxford: Oxford University Press, 1993.

Du Pont, J. E. Philippine Birds. Monograph Series No. 2. Delaware: Delaware Museum of Natural History, 1971.

Fry, C. H., S. Keith, and E. K. Urban, eds. The Birds of Africa. Vol. VI. New York: Academic Press, 2000.

Greenway, J. C. "Oriolidae." Check-List of Birds of the World. Vol. 15. Cambridge, Mass.: Museum of Comparative Zoology, 1962.

MacKinnon, J., and K. Phillipps. A Field Guide to the Birds of Borneo, Sumatra, Java, and Bali. Oxford: Oxford University Press, 1993.

Schodde, R., and S. C. Tidemann, eds. Reader's Digest Complete Book of Australian Birds. 2nd edition. Sydney: Reader's Digest Services, 1986.

Schodde, R., and I. J. Mason. The Directory of Australian Birds Passerines. Melbourne: CSIRO Publishing, 1999.

Sibley, C. G., and J. E. Ahlquist. Phylogeny and Classification of Birds. New Haven: Yale University Press, 1990.

Sibley, C.G., and B. L. Monroe, Jr. Distribution and Taxonomy of Birds of the World. New Haven: Yale University Press, 1990.

Smythies, B. E. The Birds of Borneo. 3rd edition. Kota Kinabalu and Kuala Lumpur, Malaysia: The Sabah Society and the Sabah Nature Society, 1981.

UNEP World Conservation Monitoring Centre. Threatened Animals of the World.<http://www.unepwcmc.org/species/animals/animalredlist.html>. January 2002.