 The
"Old World Warbler," when assigned to the family Sylviidae, once included
~400 species, the second largest family in the world. New biochemical information
has shown that this huge "Old World Warbler" assemblage actually represented10
or more different major evolutionary lineages; Alström et al. (2006),
Jønsson & Fjeldså (2006), Barker et al. (2004); for an
overview see a discussion of the Break-Up
of the Old World Warblers. Alström et al. (2006) began the inevitable
process of breaking them up into new families, proposing Family names for
several of the lineages and leaving others for later studies. They proposed
the Family name Cettiidae for a group of diverse 'warblers' from Eurasia,
and even a 'flycatcher' from Africa. These might now be called the Cettid
Warblers, or simply Cettids [pronounced "Chet-ids"].
Perhaps the 'base' group in the Cettiidae are the 14 species of bush-warblers in the genus Cettia. These are notorious skulkers, often heard but seldom seen. An example is Luzon Bush-Warbler (left), endemic to the mountains of northern Luzon, Philippines. In this lucky shot, we see they shy bird spreading its wings and sun-bathing in a sunbeam penetrating the otherwise thick undergrowth. This species is presumably not photographed often. Other Cettia warblers include Cetti's Warbler C. cetti, which hides in reedbeds and swamps from Europe (including s. England) to the Middle East and Pakistan. Several others skulk in the undergrowth of the Himalayas or China, and yet others are found of islands from the Greater Sundas to Tanimbar, Palau, and Fiji. It is somewhat surprising to learn these "bush-warblers" are not closely related to "bush-warblers" in the genus Bradypterus. The latter are found in the grassbird family [Megaluridae]. |
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 Among
the many surprises revealed by genetic research were data that showed that
the tailorbirds were not a unified group. Some tailorbirds prove to be
closely related to cisticolas and prinias, in the family Cisticolidae.
But the Mountain Tailorbird (right), which ranges from southern
Asia to the Philippines and Wallacea, is quite unrelated and, in fact,
is a member of this group, the Cettiidae.
The exact parameters of the rest of the Cettiidae is not currently known. So far, it appears that other members are the almost tail-less Tesia warblers and Asian Stubtail Urosphena squameiceps, and Broad-billed Warbler Tickella hodgsoni. A little less closely related are the African warblers in genus Abroscopus, the African 'flycatcher' Erythrocercus [Chestnut-capped 'Flycatcher' of west & central Africa], Green Hylia Hylia prasina (below left), and Tit-Hylia Pholidornis rushlae. Alström et al. (2006) include all of them in their proposed family. There are still many groups of sylvoid warblers to be studied. Apparently, no one has yet looked at the genetics of such common groups as the 10 species of Eremomela in Africa. These tend to be dry country specialist; one example is Burnt-necked Eremomela (below right) of the thornscrub of southwest Africa. Dickinson (2003) places this genera next to the Abroscopus warblers and Broad-billed Warbler, both found to be members of the Cettiidae, and so we tentatively assign the Eremomelas here, subject to immediate change when genetic data are published. |
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| Assuming this Family holds together upon further review, it will encompass quite an assortment of warblers. Some will be swamp and reedbed skulkers, others thornscrub denizens, some restricted to montane cloud forests, and other found in mixed species flocks in the primary jungle of west Africa and the Congo Basin. Green Hylia (above left) is one of those species. It acts more or less like a tit in the mid-canopy, rather quiet and unassuming except for its easily learned, disyllabic whistle. This is a characteristic forest sound in these tropical lowland rainforests. Its affinities have been a mystery from a long time. At various times it was treated as a warbler, a weaver, or evan a sunbird (!) because of its morphology. Its true relationships appear to be only sorting out through genetic information. | ||
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Photos: The Luzon Bush-Warbler Cettia seebohmi was in the undergrowth high on Mt. Pollis, Luzon, the Philippines, on 31 Dec 2005. The Mountain Tailorbird Orthotomus cuculatus was foraging just off my balcony at the hostel in Mt. Kinabalu Park, Borneo, Malaysia, in Aug 1988. The Green Hylia Hylia prasina was at Buhoma, Impenetrable Forest, Uganda, in July 2002 The Burnt-necked Eremomela Eremomela usticollis was in Daan Viljoen Reserve, west of Windhoek, Namibia, on 28 July 2005. All photos © 200g Don Roberson; all rights reserved. There is no "family book" covering the cettid warblers so information must be sought in a variety of texts. The next volume of HBW will cover all the sylvioid warblers. Literature cited: Alström P., P.G.P. Ericson, U. Olsson, and P. Sundberg. 2006. Phylogeny and classification of the avian superfamily Sylvioidea. Molecular Phylogenetics & Evolution 38: 381-397. |
