Turdidae
The Key to Scientific Names
Legend Overview
Turdidae Thrushes and Allies
Version: 1.0 — Published March 4, 2020
- Year-round
- Breeding
- Non-breeding
Introduction
Few distinctions in the world of bird families are as maddening as that between the thrushes and the Old World flycatchers: both families have large numbers of species, and morphological diversification over the millennia has created a great deal of overlap between them. Thrushes are generally long-bodied and strong-legged, with full chests, largish heads, and mid-sized bills. Most species are comfortable on the ground, where they often hop after buried invertebrate prey. Though they are most often attired in plumages of earth tones, with accents in rufous and contrasting streaks and spots of black and gray, some species are partially or entirely blue. Many have complex whistled and trilled songs with an ethereal resonance.
Habitat
The habitat of thrushes varies, from dense forests to grasslands, but they usually avoid extremely arid habitats.
Diet and Foraging
Thrushes feed on a wide variety of invertebrates, including insects, worms, and spiders, and various small fruits. Although some will also take small vertebrates, these rarely constitute a sizable proportion of the diet of any thrush species. During the winter months, fruit becomes an important food item for species wintering in temperate regions. Many thrushes forage for invertebrate prey on the ground by gleaning or probing the top soil layer. Other thrushes, like the bluebirds and solitaires, actively sally for insects. Some otherwise terrestrial thrushes flycatch occasionally.
Breeding
Turdids are monogamous with biparental care, and some species breed cooperatively. Western Bluebirds Sialia mexicana, for instance, frequently have helpers that aid in defending territory and feeding chicks. As with most cooperatively breeding species, the majority of helpers are males retained from previous nesting of the breeding pair. The nests of turdids typically consist of a woven cup of grass and other vegetative material, with mud being added in some species. Species living in close proximity to humans also incorporate objects like rope and ribbon into their nests. Some will also decorate their nests with moss and epiphytes. The placement of nests varies substantially; for example, bluebirds (Sialia) typically nest in tree cavities or nest boxes, whereas the solitaires typically nest on the ground or in a niche in a bank or trunk. Female turdids typically lay 1 to 7 eggs. Only female thrushes build the nest, gathering nesting material and choosing a nest site. Only females incubate as well, but both male and female provision the chicks, the male often doing the bulk of the work at that stage. Incubation generally takes 11 to 15 days. Nestlings leave after 11 to 19 days in the nest (usually less than 15), and the young are fed by the parents for 10 to 25 days after they leave the nest.
Conservation Status
Habitat loss, introduced predators, and epidemic disease are the main threats facing turdids, 39 species of which (25%) are of conservation concern (23 NT, 11 VU, 2 EN, 3 CR). The Myadestes solitaires of the Hawaiian Islands include the critically endangered Puaiohi Myadestes palmeri and Olomao M. lanaiensis, the latter of which is probably extinct, likely joining two others (M. myadestinus and M. wo ahensis) that went extinct with extensive clearing of native forests and introduction of mosquitoes carrying malaria to the islands. The critically endangered Taita Thrush Turdus helleri is restricted to three tiny and isolated forest fragments in the Taita Hills in southern Kenya; severe human population pressure on the remaining forest has intensified efforts to halt habitat destruction and undertake reforestation with native species. The endangered La Selle Thrush Turdus swalesi is restricted to the island of Hispaniola, where extensive clearance of broadleaf forest has left the species with a very limited and fragmented range. A similar situation faces the endangered Spotted Ground-thrush Zoothera guttata in southern Africa, where both the breeding and wintering grounds for this southern migrant are scattered forest remnants that are under pressure from timber harvesting and pollution by mining operations.
Systematics History
Turdidae is part of the superfamily Muscicapoidea of oscine passerines (Alström et al. 2014), within which it is sister to Muscicapidae (Barker et al. 2004, Cibois & Cracraft 2004, Zuccon et al. 2006, Johansson et al. 2008b, Treplin et al. 2008, Sangster et al. 2010). The clade of Turdidae plus Muscicapidae taken together is in turn sister to Cinclidae (Barker et al. 2004, Cibois & Cracraft 2004, Fuchs et al. 2006b, Zuccon et al. 2006, Reddy & Cracraft 2007, Johansson et al. 2008b, Treplin et al. 2008). The family limits between Turdidae and Muscicapidae have been uncertain, with members of each family at times being classified with the other. For example, the Saxicolini (which includes the Oenanthe wheatears, Saxicola stonechats, Luscinia robins, and Monticola rock thrushes) and the Copsychus shamas have often been grouped with Turdidae, but they are presently classified as part of Muscicapidae on the basis of molecular phylogenetic studies (Wink et al. 2002, Cibois & Cracraft 2004). Within Turdidae, the two main subfamilies of solitaires (Myadestinae) and thrushes (Turdinae) are clearly delineated by molecular studies (Olsson & Alström 2013, Sangster et al. 2010).
Conservation Status
Least Concern |
62%
|
---|---|
Near Threatened |
13%
|
Vulnerable |
3.6%
|
Endangered |
1%
|
Critically Endangered |
1.6%
|
Extinct in the Wild |
0%
|
Extinct |
2.1%
|
Not Evaluated |
0%
|
Data Deficient |
0%
|
Unknown |
16.7%
|
Data provided by IUCN (2024) Red List. More information