Timaliidae Tree-Babblers, Scimitar-Babblers, and Allies
Version: 1.0 — Published March 4, 2020
Introduction
This newly restricted Timaliidae includes only a subset of what was once a much more inclusive babbler family. These “tree babblers” occupy all strata of Asian forests, but only a few spend much time on the ground. Plumages are dominated by black and gray or rich brown, most species with liberal patterning in spots and streaks. Most have generic passerine proportions, although a few are less mundane: the scimitar babblers with their long, decurved, yellow bills, and the wren-babblers with their perky tail-up posture. Timaliid vocalizations are diverse and frequently heard, and some species inflate blue-pigmented throat sacs when they sing. Many species are quite social, but quite a few of the others appear to be monogamous, defending simple all-purpose territories.
Habitat
The tree babblers are forest dwellers whose habitats range from dry forest to humid rainforest, and several species are bamboo specialists.
Diet and Foraging
Timaliids feed primarily on insects and other invertebrates, mostly by gleaning them from leaves and, more commonly, branches. Some species also feed on berries, seeds, and even nectar, especially when insects are scarce.
Breeding
The tree babblers are monogamous with biparental care, and there are apparently no colonial or aggregated breeders in this family. The nests of timaliids are typically either globular or domed, and are usually built on or near the ground. Nests are generally constructed of leaves, twigs, bamboo, rootlets, and moss. Some species build more-open cup nests placed behind bark or in the hollow of a tree or log. Females lay 2 to 5 eggs, with larger clutches to the north. Although other babbler families are better studied, it appears that both males and females help with nest construction, incubation, and feeding of the chicks. With information on only a few species, incubation apparently takes about 12 days and nestlings are in the nest for at least 10 to 11 days. Much more information is clearly needed.
Conservation Status
Habitat loss and fragmentation are the main threats to timaliids, 12 species of which (24%) are of conservation concern (8 NT, 4 VU). The two vulnerable wren-babblers, Rusty-throated Spelaeornis badeigularis and Tawny-breasted S. longicaudatus, are restricted to tiny ranges in the eastern Himalayas. Both are extremely secretive and difficult to observe, and both live in areas in which their forest habitat is being harvested and converted to agriculture. In the same region, the vulnerable Snowy-throated Babbler Stachyris oglei is known from only four localities in India and one in Myanmar, and deforestation is ongoing throughout this region. Similarly, the vulnerable Nonggang Babbler Stachyris nonggangensis has a very restricted distribution along the China-Vietnam border, recent surveys finding it only in three reserves in the region.
Systematics History
Timaliidae is part of the sylvioid radiation. Recent molecular phylogenetic studies have resulted in the division of the formerly large babbler family (Timaliidae sensu lato) into five related but distinct families, one of which (the much smaller revised Timaliidae) now consists of the tree and scimitar babblers (Cibois 2003, Gelang et al. 2009, Moyle et al. 2012). Its exact position within this clade is not entirely resolved, but Timaliidae appears to be sister either to Pellorneidae (Cibois 2003) or to a clade composed of Pellorneidae and Leiothrichidae (Gelang et al. 2009, Fregin et al. 2012, Moyle et al. 2012, Alström et al. 2013a, Olsson et al. 2013).
Conservation Status
Least Concern |
69%
|
---|---|
Near Threatened |
19%
|
Vulnerable |
8.6%
|
Endangered |
0%
|
Critically Endangered |
0%
|
Extinct in the Wild |
0%
|
Extinct |
0%
|
Not Evaluated |
0%
|
Data Deficient |
0%
|
Unknown |
3.4%
|
Data provided by IUCN (2023) Red List. More information