a web page by Don Roberson |
BABBLERS Timaliidae |
|||
|
|||
Babblers were once considered a huge family of over 300 species. Studies in the mid-2000s began to clarify the situation (e.g., Cibois 2003, Alström et al. 2006, Jønsson & Fjeldså 2006) but there is uncertainty whether the huge babbler assemblage should be allocated to one or two or more families. Genetic evidence revealed that the Sylvia warblers — the original genus in the 'Old World Warblers' Sylviidae — were more closely related to Babblers than other Old World Warblers [see a discussion of the break-up of the Old World Warblers]. Additional research, especially Gelang et al. (2009), led to a "break-up of the Babblers." Cibois et al. (2010) summarized the outlines for five babbler families: tree babblers and scimitar-babblers [Timaliidae], sylvid babblers and parrotbills [Sylviidae], white-eyes [Zosteropidae], fulvettas and ground-babblers [Pellorneidae], and laughingthrushes [Leiothrichidae]. This concept was initially accepted here in my Family pages, with the proviso that the "five-family solution remains tentative and subject to future research." More recently, Moyle et al. (2012) confirmed the major clades in the babbler assemblage, but recommended that the tree-babblers, laughingthrushes, and the ground-babblers, be considered subfamilies of an expanded Babbler family [Timaliidae]. One of the reasons has to do with the amount of evolutionary time with the other related Families remaining the Sylvids and the White-eyes. I now follow that approach. The core babblers split from the White-eyes and relatives in the early Miocene, estimated at 16–21 million years ago (mya; Moyle et al., 2012). Although that is a long time ago, it is not nearly as old as, for example, the Family level groups in the broadbill assemblage [African & Green Broadbills, Asian & Grauer's Broadbills, Asities, and Sapayoa in the New World] that diverged 45–56 mya (Moyle et al. 2006). So a Family level at perhaps 20 mya or has not been on its own evolutionary path as long as many bird families. My feeling is that something that diverged in early Miocene (about 16-23 mya) is a good guideline for a minimum of age of what we call a Family. Younger divergence might better be considered subfamilies. The three main clades of the core babblers — the tree-babblers & scimitar-babblers, the laughingthrushes, and the ground-babblers — began diverging 11.2–17.8 mya (Moyle et al. 2012). The main African radiations among babblers are even younger: the origin of the Illadopsis babblers is 10-14 mya, and the radiation of Turdoides babblers to Africa is 6.4-9.9 mya. These latter divergence times recall those of the ancestor of today's Wrentit Chamaea fasciata of western North America, which began diverging from its parrotbill ancestors about 6.5-8.1 mya (Burns & Barhoum 2006). This puts some perspective on the scale of evolution. Families should be, in my opinion, the most distinctive and long-evolved of monophyletic groups. I agree with Moyle et al. (2012) that the three major clades of babblers are best considered subfamilies, and I now treat that this way. A page on each subfamily is now provided: use the links or photos below to reach them: |
|||
|
|||
Whatever your preference as to what constitutes a bird Family, all the recent research has combined to give us a much better appreciation of the relationships of many birds. It is especially interesting to understand what is not a babbler: For example, Gelang et al. (2009) found that one of a half-dozen genera of wren-babblers — the four species in genus Pnoepygidae — were not within any babbler lineage. They recommended a new family, the Pnoepygidae, for those tiny, short-tailed, "wren-babblers", which are now known as Cupwings. The remaining genera of birds termed wren-babblers (e.g., Rimator, Ptiolcichla, Kenopia, Napothera, Spelaeornis) are babblers but are assigned to various babbler subfamilies. Moyle et al. (2012) found that three aberrant "babblers" in the Philippines — Leonardina, Robsonius, and Micromacronus (the two "miniature-babblers") — plus the endemic genus Malia of Sulawesi — were not babblers at all. Where these enigmas may be placed will be the subject of upcoming papers. Beyond these, earlier dramatic findings included:
And yet beyond all this, many traditional babbler genera have proved to be paraphyletic (e.g., Stachyris is now split into 4 genera; Moyle et al. 2012). Thus the entire Babbler "apple-cart" has been turned over, sorted out, and reassigned as the evolutionary relationships have been sorted out. It is still a very large group of Asian and African birds, but today's Babbler family bears only partial resemblance to the 'traditional' babblers of yore. |
|||
| Photos: The two shots of Sulawesi Babbler Pellorneum celebense are from Gunung Ambag, Sulawesi, on 5 Oct 2011. The Rufous-capped Babbler Cyanoderma ruficeps was photographed in Foping Nature Reserve, Shaanxi, China, on 13 Nov 2010. The huddled group of Bare-cheeked Babbler Turdoides gymnogenys was at Etosha NP, Namibia, in July 2005. All photos © Don Roberson; all rights reserved. | |||
Bibliographic notes There is no recent "family book" covering the Babblers but excellent coverage is in Collar & Robson (2007). The account is wonderful, with exceptional photos, although it is not quite up to speed with the most current taxonomic findings. Literature cited:
|
In
the Old World tropics live hundreds of elusive small to mid-sized birds
— babblers! Often first located by sound, many species are elusive in
the shadows and undergrowth, even where they are common. Just one
example is the only babbler to cross Wallace's Line, the Sulawesi Babbler (left). 
