IDENTIFICATION – Dark-throated Thrush is a passerine bird of the thrush family, and it breeds in the Urals (also a rare winter visitor to the extreme southeast of many European regions). That is recalled Fieldfare in structure and behavior, but the tail is relatively shorter. The two subspecies appear noticeably diverse in the field and are best considered separately.
Black-throated Thrush (race atrogularis): In all but juvenile plumage may show a yellowish bill base, a hint of a slightly lighter supercilium, a slightly paler grayish-brown rump, and some contrast between lighter and darker areas of wing. The migratory and large distinctive thrush dull rufous underwing coverts are hard to see in the field. Adult male in worn plumage in spring/early summer distinctive, with dull grayish-brown upperparts, dark tail, and black face, throat, and chest contrasting with off-white of the remainder of underparts.
In fresh autumn and winter plumage, black of throat partly obscured by pale feather tips but still evident. Also, the adult female bird is a bit duller in general, being a little browner-gray above and drabber below with underparts sullied grayish and a throat is bit whitish with dark mottling and dark malar stripe. Also, a gorget of intense dusky mottles across the upper breast is the most noticeable feature.
First-years are drabber than an adult, young females having only indistinct smudgy markings on the malar region and breast, often extending well down onto flanks on a dull grayish-brown background; young males have more evenly mottled throat and breast. Only the drabbest females are likely to cause problems, but smudgy streaking, not spotting, on breast and upper flanks on the grayish background are distinctive.
However, confusion could occur with those individuals of Dusky Thrush that lack rufous-chestnut on the wing: but 1st-year Black-throated has more uniform, paler upperparts, fine, diffuse dark streaking on flanks (Dusky has large black spots or arrowheads, often tinged with rufous), and paler ear-coverts, while supercilium is usually less prominent and pale half-collar is lacking.
The juvenile resembles the adult female but has buff shaft streaks to upperparts, a more strongly spotted breast (uppermost spots may almost coalesce and hint at an adult female’s dark gorget), and a more obvious, buff-tinged, supercilium. Recalls juvenile Song Thrush, but prominent spotting restricted to the breast (flanks have only weak crescentic markings).
Moreover, the Red-throated Thrush (T. r. ruficollis); is as with the Black-throated form, has dull rufous underwing coverts and from 1st-year plumage onwards may show yellow base to bill. Adult male differs from male Black-throated in having brick-red instead of black on the face and throat, somewhat paler grey-brown upperparts, and rufous outer tail.
In fresh plumage in autumn and early winter, brick-red areas narrowly scaled with whitish. The adult female has a more rufous, less red tone to supercilium, lower face, and throat, and the throat is mottled with whitish and dark brown in fresh plumage, largely obscuring rufous (which is often reduced to a diffuse pectoral band); upperparts are browner-toned.
First-years resemble adult females, with rufous breasts largely obscured by feather edges and black speckles. The only other thrush with rufous in the tail is Naumann’s, 1st-years of which could be confused with either First-year or adult female Red-throated, but Naumann’s also has rufous rump, is more extensively rufous below (with triangular rufous markings, or at least diffuse rufous streaks, extending well down flanks and often onto under tail coverts).
And it has more contrasting pale wing panels, darker ear coverts (with the pale patch below the eye), and a more prominent supercilium. Both forms feed more in open than most other Asian thrushes, perching freely on tops of bushes and trees and feeding on the ground in the manner of Fieldfare shy and wary.
SEX/AGE See Identification however First-years may be aged by pale tips to greater coverts. A recent study shows that the other subspecies are Red-throated Thrush (T. r. ruficollis); Black-throated Thrush (T. r. atrogularis).
VOICE – Dark-throated Thrush call includes a soft ‘chuk’, a short squawk, a weak ‘seep’, and a harsh ‘chak’ (often repeated to form a Fieldfare-like chuckle). Also gives a hysterical Common Blackbird-like chatter of alarm. Dark-throated Thrush song includes repeated phrases as in Song Thrush, interspersed with Common Blackbird-like phrases.
TAXONOMY – Intermediates between the two are not infrequent, but as a zone of hybridization appears to be quite narrow Black-throated Thrush is sometimes accorded full species status as T. atrogularis.
GEOGRAPHICAL VARIATION – It is marked. by 2 races (both illustrated). Differences outlined under Identification. Black-throated race atrogularis breeds further north and west than red-throated form, just reaching our region. Red-throated nominates race merely a vagrant. However, it is uncommon in eastern Myanmar to Arabian Peninsula. Also, a vagrant bird is found in Thailand, Japan, Taiwan, China, and most part of Western Europe within its normal range.
HABITAT – Dark-throated Thrush is common on breeding grounds, but rare in the extreme southeast of our region in winter; most winter is further east in Southern and Central Asia. Black-throated form breeds west to the Urals in varied and coniferous forests in hilly districts.
However, in the winter, its favorite place is the cultivation and bushy areas. Red-throated race a vagrant (Europe). This bird species breed along the edges of clearings in coniferous or diverse deciduous forest, frequently in the undergrowth of Siberian Pine (Pinus sibirica) or varied spruce-fir forest, particularly along watercourses or in marshy areas.