Black-throated Trush Turdus atrogularis

From 10 Nov until 20 Nov 2013 we were watching raptor migration at Thoolakharka, Annapurna, western region of Nepal (NW of Pokhara city). The altitude was about 2000 m asl and habitats were dominated by broad-leaved forest along the hillsides. There were lots of berries in some trees and they attracted flocks of Black-throated Trushes and Black Bulbuls Hypsipetes leucocephalus. We also saw several scarcer trushes: Grey-winged Blackbirds Turdus boulboul, Chestnut Trushes Turdus rubrocanus, Mistle Trushes Turdus viscivorus and one Red-throated Trush Turdus ruficollis. They were in the same area but not in the flocks of Black-throated Trushes.

The flocks were quite wary and liked dark places and shadow so not many good photos were taken, but they were nice to look at using a scope. Hundreds of birds were seen on several days. Many of the photos below were taken in very poor light.

First, a compilation of calls. (0-0.47) a male from a treetop, making calls resembling those of Fieldfare Turdus pilaris but thinner (12 Nov, rec 2023). (0.48-1.18) Short alarm-call like notes (resembling alarm calls of Eurasian Blackbird Turdus merula) and then again Fieldfare-like chattering (12 Nov, rec 2014). (1.19-1.25) Again this chattering call (15 Nov, rec. 2041). (Background species include Black Bulbul, Common Hill Partridge, Whiskered Yuhina, White-tailed Nuthatch, Fire-breasted Flowerpecker, Grey-hooded Warbler, Chestnut-crowned and White-crested Laughingtrush).

Black-throated Trush is very variable-looking for a Turdus. There is a distinct sexual dimorphism and the first post-juvenile plumage is still immature. In addition to this, there is variation which seems not to be straightly related to sex or age: the distinctness of the supercilium is very variable from none to almost as distinct as in Redwing Turdus iliacus, the bill may be almost totally black and so on. In this photo there is a male at the top and a female, first-year, at the bottom. The leftmost bird is odd-looking: wings and rump sides show some brownish and the flank patterning is of somewhat heart-shaped spots, no streaks as in most. It may have some Dusky Trush Turdus eunomus - genes.

Birds like this are males and at least most often adults. The black breast may still be more uniformly black than this. In autumn,the throat is possibly always streaked. Flanks and belly are almost unstreaked greyish.

The two birds in the front are females and at least the one in the middle is a first-year. Most of the greater coverts are unmoulted and have whitish tips. This seem to be the norm - most of the greater coverts were unmoulted. Also the tertials of first-year birds are more worn than in adults. The other ageing criterium - the shape of the tail feathers, was very seldom visible in our views at Thoolakharka. Streaked underparts as in these birds was quite a frequent feature. Most birds like these are first-winter females, I think. Note that the left bird has a much more distinct supercilium.

Some more variation shown here. Most individuals have a darkly.streaked breast and paler belly and flanks with a distinct border. The blackness of the breast and streakness of flanks was very variable.

Note pale tips to the greater coverts of the left bird - so it is a first-year and in addition probably a male. The right bird should be an adult male.

The underparts of this individual are of the most common "intermediate" type. These should include first-year males and adult females. The spotting on the breast is blackish and varies: some have more blackish than pale greyish as this bird, some have more pale greyish. The streaking on the flanks is slightly more brownish, but despite searching, no birds with a rufous tinge in these streaks was found.

The right bird has a distinct supercilium - some had an even more distinct one, almost as in Redwing. The underparts of this bird are of the streaked type. No such distinct supercilium was seen in birds with the blackest breast- the adult male type - it occurred in the "intermediate" type. Many birds almost lack a supercilium altogether, but most show an indistinct one. This bird also seems to have an almost completely black bill which occurred in some others as well.

Black-throated Trush is neither a large trush like Fieldfare or Mistle Trush, nor a small trush such as Redwing or Song Trush Turdus philomelos, but somewhat intermediate. In flight, it is quite short-tailed and long-winged and the flight action is more similar to one of the small species.The underwing coverts are reddish, but this is difficult to see in the field.