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The spiny forest of southwestern Madagascar is one of the world's strangest habitats, dominated by tall, spiky Alluaudia procera trees. Atop one of those trees is one of Madagascar's strangest birds, the Sickle-billed Vanga (left). It has a white head and underparts and a black mantle; its long decurved bill, though, may be better seen in the silhouetted shot (above). These are "the most noisy and characterful members of the bird community" in the spiny desert (Morris & Hawkins 1998). They are often in groups of 3 to 10, giving loud "waaah" calls, like a baby crying. The long, decurved bills are used to "probe into holes and crevices in dead and live trees, lever off bark, and glean insects from the surface: (Morris & Hawkins 1998). In that same forest is another black-and-white vanga with a very short, wedge-like bill that it uses to strip the bark off dead branches and tree trunks. When it finds an insect it will batter it against the wood. This is Lafresnaye's Vanga (below). |
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Many of the vangas, including Sickle-billed Vanga, often associate with
other birds in mixed species flocks working through the forest. All the
vangas require woodland of some type — from thick humid jungle to dry open
spiny forest — and so are good indicators of the presence of native habitat.
Several of the vangas are the "core" species of these foraging flocks.
The Lafresnaye's Vanga (above) is different. It does not join flocks
but forages alone or in small single-species flocks. Its The flight is
powerful (this one above right is just taking off) between foraging sites,
and then it works the dead tree from bottom up, "spending much time to
remove bark, often working with head pointed down" (Langrand 1990).
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Traditionally, vangas were considered to be an endemic family to Madagascar,
with just 14 species. The number of species assigned to Vangidae has changed
recently (see below), but like the Hawaiian Honeycreepers or the Darwin's
Finches of Galapagos, this island family arose in isolation and evolved
to fill numerous niches. All of them prey on invertebrates or small herps
to one degree or another. Some have evolved heavy wedge-like bills for
breaking off bark, like that of Van Dam's Vanga (below left),
a species restricted to deciduous forest of the northwest where it is rare
and local. One species fills the niche of a chickadee (Red-tailed Vanga
Calicalius
madagascariensis), another that of a nuthatch (the Nuthatch Vanga Hypositta
corallirostris looks so much like a nuthatch that its alternate name
is "Coral-billed Nuthatch), and yet another has a huge casqued bill, recalling
hornbills, and is known as the Helmetbird Euryceros prevostii (it
is also the most remote species, restricted to extreme northern Madagascar).
Another,
Chabert's Vanga (below right) forages with mixed
species flocks and sallies out like a small flycatcher, or glides like
a small wood-swallow. Although difficult to see in this shot, it has bare
blue skin around its eye (like the wattle-eyes of Africa).
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| Taxonomically, the vangas were known to be related to African families
such as the helmetshrikes, wattle-eyes and batises (indeed, Sibley &
Ahlquist 1990 and Sibley & Monroe 1990 lumped all these groups together)
but most authorities considered them a separate family (e.g., Dickinson
2003). But the newest biochemical evidence (e.g., Fuchs 2004) shows that
the closely related groups fall into three different clades this way: the
batises & wattle-eyes are one group, the traditional bush-shrikes are
another group, and the helmet-shrikes, vangas, and flycatcher-shrikes are
the third group. These data show that helmet-shrikes and vangas are very
closely related, and it possible that in the long run these two families
may be grouped together. It is even possible they will all be subfamilies
of the Malaconotidae some day. For the moment I retain vangas as an endemic
family to Madagascar. [For the moment, we put the flycatcher-shrikes in
with the helmet-shrikes (Prionopidae).]
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| Photos: The Sickle-billed Vanga
Falculea palliata was near Ishfay, north of Tulear, southwestern Madagascar,
on 20 Nov 1992. The Lafresnaye's Vanga
Xenopirostris xenopirostris was in that same spiny forest the same
day. The Van Dam's Vanga Xenopirostris
damii was photographed at Ankarafantsika in the Ampijoroa Forest on
29 Nov 1992. The Chabert's Vanga Xenopirostris
damii was near Perinet, in eastern Madagascar, in mid-Nov 1992. I sketched
Crossley's "Babbler" Mystacornis crossleyi at Perinet on 2 Dec 1992.
Photos
& sketch © 2000 Don Roberson, all rights reserved.
Bibliographic note Family Book: There is no family book per se of which I
am aware; even the fine book that include bush-shrikes and helmet-shrikes
(Harris & Franklin 2000) does not cover the vangas. Good photos of
all vangas (even the new ones) are in Morris & Hawkins (1998), and
their habitats covered by Dee (1986). I'm sure the
Handbook of the Birds
of the World series will be impressive when it reaches this family.
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Other literature cited:
Cibois, A., E. Pasquet, and T.S. Schulenberg. 1999. Molecular systematics of the Malagasy babblers (Timaliidae) and Warblers (Sylviidae), based on cytochrome b and 16S rRNA sequences. Molecular Phylogenetics & Evolution 3: 581-595. |