Vanga shrikes

(Vangidae)

Class Aves

Order Passeriformes

Suborder Passeri (Oscines)

Family Vangidae

Thumbnail description
Small to medium-sized shrike-like birds with a wide variety of body forms and lifestyles, essentially restricted to forest

Size
5–13 in (12–32 cm); 1.2–11 oz (35–300 g)

Number of genera, species
11 genera; 16 species

Habitat
Primary eastern rainforest, western deciduous forest, and southern spiny bush; some species locally in plantations and wooded areas not far from primary forest

Conservation status
Endangered: 1 species; Vulnerable: 3 species; Near Threatened: 1 species; Data Deficient: 1 species

Distribution
Madagascar; one species locally on the Comoro Islands

Evolution and systematics

The startling range of body forms found in the vangas has provoked endless taxonomic confusion. Currently they are considered a monophyletic group within the large shrike assemblage, but members of the group have variously been considered nuthatches, shrikes, orioles, and bulbuls. In common with many other Malagasy birds, diversity is comparatively rich at the generic level but there are few species in each genus. All are at present included in the same sub-family.

Physical characteristics

The vangas display a remarkable variety of body formats over a relatively small size range. They start with the small vireo-like Calicalicus species, which glean small insects from foliage, through the nuthatch-like Hypositta, via the wood-swallow-like Chabert's vanga (Leptopterus chabert), and the electrified blue vanga (Cyanolanius madagascarinus), the thick, powerful-billed hook-billed vanga (Vanga curvirostris), Xenopirostris, and white-headed Leptopterus viridis vangas, to the larger and more extravagantly adorned sicklebilled vanga (Falculea palliata) and helmet vanga (Euryceros prevostii). The sicklebilled vanga is a large vigorous bird with a bill that is evidently suited to winkling invertebrates from their hiding places. The helmet vanga sports a huge flattened pale-blue instrument that has no apparent foraging advantage, given that the species prefers small insects to opening coconuts.

In general, apart from their bills, vangas are similar in form in that they have rather stocky solid bodies, short wings, medium-length tails, short and rather strong legs, and large eyes. About the only exception to this is the Chabert's vanga, which has rather long wings suited to its largely aerial life. It is in the bill and head structure that the vangas really distinguish themselves. The 16 species of vanga can be divided up into three main groups—relatively slender, narrow bills for gleaning and general insectivory (red-tailed [Calicalicus madagascariensis], red-shouldered [C. rufocarpalis], nuthatch [Hypositta corallirostris], Tylas [Tylas eduardi], Chabert's, and blue vangas), laterally flattened bills for breaking open insect refuges or killing large invertebrates or small vertebrates (white, Pollen's [Xenopirostris polleni], Van Dam's [X. damii], Lafresnaye's [X. xenopirostris], and hook-billed), and the oddities, sicklebilled and helmet vangas.

Just over half the species are sexually dichromatic (redtailed, red-shouldered, rufous [Schetba rufa], the Xenopirostris species, white-headed, blue and Bernier's [Oriolia bernieri], and the nuthatch vanga). The Tylas seems to be most unusual in having one form (the nominate) monochromatic, and the other (T. e. albigularis) possibly dichromatic, although the

latter form has been seen so few times the question is not yet resolved. Most species are some combination of black and white, with some showing larger areas of red. The smaller vangas are brightly colored, the red-shouldered and red-tailed with black bibs, gray caps, and reddish wingpatches, the blue vanga with an ultramarine back and bill base. Chabert's vanga is unique in the family in having brightly colored blue skin around the eye. Rufous and helmet vangas are black, red, and white with pale blue bills (though of dramatically different form), while the other species are essentially gray, black, and white. Juveniles of many species and females of some (Pollen's, Van Dam's) show variable amounts of orange underneath, while in the Tylas vanga both sexes are orange-bellied. The nuthatch vanga is the only species with an orange as opposed to grey, blue, or black bill.

Distribution

With one strange exception, vangas are endemic to the mainland and adjacent small islands of Madagascar. They are found all over the island, being most scarce on the central plateau region where there is scarcely any natural habitat left. The curious exception to this rule is that of two populations of blue vangas in the Comoro islands, 125 mi (200 km) from the Malagasy mainland. The presence of this species in the Comoros is all the more remarkable given the fact that it is one of the more forest-limited vangas, never being seen far from the forest canopy in the west and east of Madagascar. It is very difficult to imagine such an apparently sedentary and habitat-limited species suddenly setting out over the open ocean, particularly when there are so many other more mobile species (in particular Chabert's vanga) that might have been expected to make the journey.

Habitat

Vangas are essentially birds of primary forest, like most other endemic Malagasy species. This means that they are absent from most of the high plateau region, and in coastal areas, essentially absent from secondary forest, plantations, or built-up areas. The two exceptions to the rule are hook-billed and Chabert's vangas. The latter may be found in degraded and secondary plantations a fair way from primary forest, where it appears to be able to hold territories and breed. Chabert's vanga is very mobile and may visit plantations (especially eucalyptus or mango) in search of pollinating insects tens of miles from primary forest. But neither has ever been recorded, for instance, from the centers of the larger cities.

The more adaptable species (hook-billed, Chabert's, white-headed) are found in all types of primary forest (eastern rainforest, western deciduous forest, and southern spiny subdesert), although populations in different forest types are subspecifically distinct in all three species. Blue, rufous, and Tylas vangas are found in both east and west; they are all restricted entirely to primary forest, and rufous and Tylas vangas have different subspecies in the west. The sicklebill occurs only in the west and south, although it manages to get by in the northern parts of the east, where forests are transitional. All the other species are limited either to southern spiny subdesert (Lafresnaye's, red-shouldered), western deciduous (Van Dam's), or eastern rainforest (Pollen's, Bernier's vangas, helmet vanga, and nuthatch vanga). The latter three species seem to be limited to the lower elevations in the rainforest, and helmet and Bernier's vangas to the northern half of the rainforest belt. Pollen's vanga seems to be much more common in the southern half of the rainforest than the north, and may be more common at higher altitudes. Hypositta perdita, described recently from juvenile specimens, is only known from rainforest at low altitude in the far southeast.

Behavior

Most vangas are found in pairs (during the breeding season), small groups, and often in large multi-species feeding flocks, which generally consist of vangas but often include other small passerines such as jerys, drongos, and cuckoo-shrikes. Two species (the sicklebilled and Chabert's vangas) are quite gregarious and can be seen in flocks of 6–32. Vanga shrikes are almost strictly forest dwellers, with the exception of a few species that will reside in both forest and savanna. Because of this limited habitat, long-range flight of vangas is often awkward and slow, even in the most powerful of short-range flyers. Some species (notably the sicklebilled, Lafresnaye's, Van Dam's, helmet, and white-headed vangas) are known for a distinctive loud whirring noise from their wings in flight. As a whole, vangas are a highly vocal group with diverse calls within the family; this is beneficial for tracking the birds while in feeding flocks with other vanga species.

Feeding ecology and diet

All vangas are essentially active seekers after exposed or hidden invertebrate or vertebrate prey. In line with bill form, the species can be separated into three basic groups—gleaners, predators/substrate strippers, and other species. The gleaners include the smaller Calicalicus and Hypositta species, which take small insect prey from substrates, the latter genus directly from trunks and large branches while moving in the manner of a nuthatch. The Calicalicus vangas glean from leaves and twigs. Blue vangas have quite conical-shaped bills that they use to extract insects from the tips of narrow canopy branches. Even longer and more conical is the bill of Chabert's vanga, which is used as a gleaning instrument in the canopy as well as for catching flying insects, particularly around flowers. Tylas vangas take larger invertebrates such as caterpillars from leaves. The heavy-billed vangas (Pollen's, Van Dam's, Lafresnaye's, rufous, white-headed, Bernier's, and hook-billed) exploit the mass of their bills to great advantage. The Xenopirostris vangas (Van Dam's, Pollen's, and Lafresnaye's) are capable of breaking off bits of dead branch, levering off mats of moss adhering to branches, opening insect cocoons, and crunching up heavily armored Gasteracantha spiders. The longer and more raptor-like bill of the hook-billed vanga is used for tearing apart small vertebrates, often through the use of a horizontal tree-fork in which to wedge the prey. Chameleons, bats, geckos, frogs, and even other birds are dealt with in this way. Rufous vangas eat rather similar kinds of food, but hunt for it in a different way. They spot prey by its movement, and so the actual species eaten are very different from those consumed by the hook-billed vanga. The Rufous vanga takes cockroaches, scorpions, and ants from the forest floor, and katydids and beetles from the undersides of understory leaves. The white-headed vanga, having a rather less substantial bill than the latter species, is more of a generalist, and while quite capable of killing and eating small chameleons, will also occasionally take fruit. Blue and Chabert's vangas have also been recorded eating fruits. The Bernier's vanga uses its triangular-shaped bill to dig into rotting masses of vegetation, especially those in the bases of Pandanus trees, from which it then energetically flings debris in search for invertebrates.

The two odd-billed species (sicklebilled vanga and helmet vanga) provide an object lesson in the interpretation of structural adaptation. For sicklebills, the bills are used as one might predict, to probe deeply into holes and recover well-hidden invertebrate larvae. The long powerful neck of this species is a great advantage in twisting the bill around curves in holes. By contrast, the helmet vanga uses its remarkable bill for little more than crunching up medium-sized invertebrates. It often displays great dexterity in sally-gleaning some invertebrate from a leaf or branch in a manner very similar to a rufous vanga, and likewise takes much prey from the ground.

Reproductive biology

Aside from studies on one or two species, not much is known of vanga reproduction. Like most Malagasy passerines, the breeding season is from October to December, in the early part of the warm rainy season. Most species lay two or three eggs, whitish or pinkish with dull reddish or brown speckles, in a cup-shaped nest, constructed by both male and female. Hook-billed, rufous, helmet, sicklebilled, and the Xenopirostris vangas place their nests in a tree fork between 3 and 16 ft (1–5 m) from the ground. The smaller species, especially Tylas, blue, Chabert's, and nuthatch vangas, place their nests higher in the canopy, and so are more difficult to study.

Nuthatch vangas attach their nest to a main trunk, often in a slight crevice. Blue vangas choose a site near the end of a branch near the crown, as do Chabert's vangas.

By far the best studied species is the rufous vanga, which has a cooperative breeding system where young males contribute to the upbringing of the young.

Several species of vanga produce beautiful calls. The rufous vanga produces a wide array of echoing and bell-like noises, many as a duet between male and female of a pair. Helmet vangas, apparently the closest relation to the rufous vanga, make similar calls, while the Xenopirostris vangas are easily detectable via their piercing descending whistle. Social species like the sicklebilled vanga make a lot of contact calls, and the Malagasy name of this species, Voronzaza (baby bird), reflects accurately a particular call that sounds like a baby crying. The red-shouldered and red-tailed vangas sing loud simple songs from the canopy, while the nuthatch vanga barely makes any discernible sound at all. The hook-billed vanga is unusual in clapping its bill together as part of a threat display.

Conservation status

Given that most vangas are tied closely to primary forest, and that Malagasy primary forests are under considerable threat, the future of many members of the family is uncertain. The most threatened species are Van Dam's vanga, which is found only in two widely separated populations in highly threatened western deciduous forest, and the lowland rainforest specialists helmet and Bernier's vangas. The latter two species are also only found in the northern half of the rainforest, in which zone lowland forest is fast disappearing due to slash-and-burn cultivation. Bernier's vanga in particular seems to have rather a patchy distribution, being absent from some areas of apparently suitable habitat. The newly described red-shouldered vanga is limited to dense Euphorbia scrub in the south-west of the country, and while this forest occurs on poor soils that are difficult to cultivate, pressure for land from a rising human population has led to recent significant clearance, putting this species under threat in its limited range. There are also some species that have regionally distinct populations that are much more threatened. The Comoros populations of blue vangas are very rare, in particular Cyanolanius madagascarinus bensoni, known from very few sightings and a single specimen from Grande Comore (Ngazidja) and Moheli (Mweli). The western form of the Tylas vanga, Tylas eduardi albigularis, seems very rare and sparsely distributed, being apparently most common in or near mangroves.

Significance to humans

Most vangas are primary forest species and, being too small to hunt, are not particularly well-known to local people. Some species, notably the sicklebilled vanga, are large and noisy enough to make themselves conspicuous wherever they occur, and some desultory hunting of this and other species occurs when they cross paths with small boys equipped with catapults. However the main relevance these species have to humans is probably in their amazing diversity of form and function, one of the main attractions for wildlife tourists and birdwatchers as well as a fertile source of research for scientists.

Species accounts

List of Species

Rufous vanga

Schetba rufa

taxonomy

Schetba rufa Linnaeus, 1766. The rufous vanga is the sole occupant of its genus. It has two subspecies, the nominate and long-billed form in eastern Madagascar and S. r. occidentalis, somewhat shorter-billed, in the central parts of the west.

other common names

French: Artamie rousse; German: Rotvanga; Spanish: Vanga Rufa.

physical characteristics

The rufous vanga is a medium-sized vanga, with short wings and a medium-length tail, and a strong head and neck. It has a thick and slightly hook-tipped bill, and large eyes. The head, throat, and breast of the male is glossy black, while the female has a black cap and a ghost of the male pattern in pale gray on the throat and breast. The underparts of both sexes are white, and the backs and tails bright rusty red. The bill is pale blue and the legs blackish.

distribution

The eastern form of the species is found in lowland forest from Marojejy National Park in northern Madagascar to Andohahela National Park in the south. The western subspecies occurs in primary western deciduous forest from just north of the Mangoky river to the Sambirano rainforest belt in the northwest.

habitat

In the eastern rainforests, the rufous vanga is rather patchily distributed in lowland forests. It seems to be exclusively limited to forests with large trees and a fairly open understory; in these conditions it is fairly abundant. It has not been recorded at higher altitudes than about 3,300 ft (1,000 m), and is most common in forests about sea-level.

In the west, rufous vangas are found only in areas of primary deciduous forest. It is rarely found in degraded or open areas.

behavior

The rufous vanga is characteristically perched on a low liana or branch. Often the birds travel in family groups, and individuals may sit on particular perches for several minutes. In the early

morning and late afternoon birds move into the canopy to sing. Much food is taken from the ground.

feeding ecology and diet

Rufous vangas sit still for long periods looking for movement of potential prey. Finding such prey is difficult if the substrate against which prey might be detected is itself moving, so foraging outside the calm forest interior is likely to be unproductive. In addition, the stable territories of rufous vangas need to contain food resources all year round, and, during the dry season, only shaded and cool areas maintain enough humidity to permit enough insect life to survive on the forest floor.

reproductive biology

Rufous vangas occupy apparently stable territories in the forest interior. The nest is built in a tree fork or exceptionally in a rock crevice, of spiders webs, lichens, small flakes of bark, etc. Both sexes contribute to construction, resulting in a neat hemispheric or inverted conical bowl. Usually two or three eggs are laid, off-white with darker reddish markings. During the nestling phase, young males from the previous year, distinguishable by the black spotting on the breast, help feed the young.

conservation status

Despite being limited to the interior of lowland rainforest and dry deciduous forest, the rufous vanga is not currently considered threatened, as it has a fairly large range (including many protected areas) and is common where it occurs. However this situation could change, particularly in the west where forest destruction, even in reserves, is occurring rapidly.

significance to humans

None known.

Hook-billed vanga

Vanga curvirostris

taxonomy

Vanga curvirostris Linnaeus, 1766. The hook-billed vanga is in a genus of its own. There are two subspecies, the nominate, which is widely distributed in rainforest and west of Madagascar, and V. c. cetera, limited to the southern spiny forests.

other common names

French: Vanga écorcheur; German: Hakenvanga; Spanish: Vanga de Pico Curvo.

physical characteristics

The hook-billed vanga has a slim body, short wings, long tail, a long neck, a relatively heavy head, and a thick black bill. Male, female, and juvenile are similar. The underparts are pure white, the head has a black nape-band. The mantle is also black, with wide pale fringes to the greater and median coverts. The base of the tail is pale gray.

distribution

The hook-billed vanga occurs all over the east in plantations not too far from primary forest, gardens, lowland, and mid-altitude forest. It is relatively scarce in rainforest. It is absent from the high plateau except in large areas of primary forest. In the west and south it is more common, especially in the fringes of primary deciduous and spiny forest.

habitat

In the east, the hook-billed vanga is largely a bird of forest and forest edge, though occasionally found some way from the forest. In the west, it is found most commonly in dense forest, particularly around regenerating gaps.

behavior

The hook-billed vanga is often difficult to find, as it feeds high in dense vegetation. The song is a short high single whistle, very difficult to locate. Imitiation of the song will often bring the bird flying in overhead to investigate, as they are very territorial.

They do not really follow mixed-species flocks, but they are sometimes seen on the periphery of groups. They are usually seen in pairs, although the couple may be widely separated.

feeding ecology and diet

The hook-billed vanga forages mostly in dense vegetation where it will tear open leaf-clumps or loose bark in search of invertebrates. When looking for chameleons, the hook-billed vangas move rapidly through the understory, hopping from vertical stem to vertical stem, looking intently for the shapes of chameleons. Hook-billed vangas take prey up to the size of a medium-sized chameleon or a bird or bat.

reproductive biology

The pair constructs a nest in the fork of a tree, often quite low down, and the female lays in it two or three whitish or reddish eggs. Pairs seem to be very territorial, and singing birds from adjacent territories may end up fighting or loudly bill-clapping at each other.

conservation status

Not being limited to primary forests and having a wide distribution, the hook-billed vanga is not considered threatened.

significance to humans

None known.

Resources

Books

Dee, T. J. The Endemic Birds of Madagascar. Cambridge, United Kingdom: ICBP, 1986.

Langrand, O. Guide des oiseaux de Madagascar. Paris: Delachaux et Niestlé, 1995.

Milon, P., J. J. Petter, and G. Randrianasolo. Faune de Madagascar 35: Oiseaux. Tananarive and Paris: ORSTOM and CNRS, 1973.

Morris, P., and F. Hawkins. A Photographic Fieldguide to the Birds of Madagascar. Robertsbridge, East Sussex: Pica Press, 1998.

Periodicals

Appert, O. "La répartition géographique des vangidés dans la région du Mangoky et la question de leur présence aux différentes époques de l'année." Oiseaux et R.F.O. 38 (1968): 6–19.

Appert, O. "Zur biologie der Vangawurger (Vangidae) sudwest-Madagaskars." Orn. Beob. 67: 101–133.

Eguchi, K., S. Yamagishi, and V. Randrianasolo. "The Composition and Foraging Behaviour of Mixed Species Flocks of Forest-living Birds in Madagascar." Ibis 134(1993): 91–96.

Goodman, S. M., A. F. A. Hawkins, and C. A. Domergue. "A New Species of Vanga (Vangidae) from South-western Madagascar." Bulletin of the British Ornithologist's Club 117(1997): 5–10.

Goodman, S. M., M. Pidgeon, A. F. A. Hawkins, and T. S. Schulenberg. "The Birds of South-eastern Madagascar." Fieldiana Zoology 87 (1997): 1–132.

Griveaud, P. "Le peuplement ornithologique de Madagascar-origines-biogéographie." Cahiers ORSTOM série Biologie 4(1967): 53–69.

Hawkins, A. F. A. "Recent Observations of the Western Tylas vanga, (Tylas (eduardi) albigularis, Vangidae)." Bulletin of the African Bird Club 2 (1995): 13–16.

Hawkins, A. F. A. "Altitudinal and Latitudinal Distribution of East Malagasy Forest Bird Communities." Journal of Biogeography 26 (1999): 447–458.

Hawkins, A. F. A. "The Importance of Foraging Strategy to the Habitat Selection of the Rufous vanga (Schetba rufa, Vangidae) in the western forests of Madagascar." Ibis (submitted).

Hawkins, A. F. A., and L. Wilmé. "Effects of logging on forest birds." In Economy and Ecology of a Tropical Dry Forest in Madagascar, edited by J. U. Ganzhorn and J. P. Sorg, 203–213. Primate Report (Special Issue) 46 (1996): 1.

Hawkins A. F. A., M. Rabenandrasana, C. V. Marie, O. M. Rabeony, R. Mulder, R. E. Emahalala, and R. Ramariason. "Field Observations of the Red-shouldered Vanga Calicalicus rufocarpalis: A Newly Described Malagasy Endemic." Bulletin of the African Bird Club 5 (1997): 30–32.

La Marca, G., and R. Thorstrom. "Breeding Biology, Diet and Vocalisation of the Helmet Vanga, (Euryceros prevostii), on the Masoala Peninsula, Madagascar." Ostrich 71 (2000): 400–403.

Rand, A. L. "The Distribution and Habits of Madagascar Birds." Bull. Amer. Mus. Nat. Hist. 72 (1936): 143–499.

Yamagishi, S., and K. Eguchi. "Comparative Foraging Ecology of Madagascar Vangids (Vangidae)." Ibis 138 (1996): 283–290.

Yamagishi, S., E. Urano, and K. Eguchi. "Group Composition and Contributions to Breeding by Rufous Vangas (Schetba rufa) in Madagascar." Ibis 137 (1995): 157–161.

Organizations

African Bird Club, c/o BirdLife International. Wellbrook Court, Girton Road, Cambridge, Cambridgeshire CB3 0NA United Kingdom. Phone: +44 1 223 279 800. Fax: +44-1-223-277-200. E-mail: birdlife@birdlife.org.uk Web site: <www.africanbirdclub.org>

Working Group on Birds in Madagascar and the Indian Ocean Islands. World Wide Fund for Nature. Antananarivo 101, BP 738 Madagascar. Phone: +261 3207 80806. E-mail: wfrep@dts.mg

Frank Hawkins, PhD