(587) Geokichla citrina citrina (Latham).
THE NORTHERN ORANGE-HEADED GROUND-THRUSH.
Geocichla citrina citrina, Fauna B. I., Birds, 2nd ed. vol. ii, p. 148.
Geokichla citrina citrina, ibid. vol. viii, p. 624.
This Orange-headed Ground-Thrush has an immense range and may eventually have to be divided into three races—a paler and slightly larger form from the extreme West and a more richly- coloured, very big form from the extreme East, Yunnan and Setchuan, with an intermediate form in the country between. At present only one form is recognized from Murree and Kuman to Yunnan, in Burma extending South to the North of Tenasserim and East to the Shan States, Western Siam and the Langbian Peak in Annam. It breeds throughout the whole of this range between the foot-hills and about 5,000 feet and, just recently, Law has dis¬covered it breeding in the plains of Bengal at Baraset.
The dividing-line in the breeding range of this race and the Malayan form innotata is impossible to define, as over an enormous area from Tenasserim and South-West Siam to the Malay States specimens occur, some of which are intermediate between the two, and many from the same area which would appear to be quite definitely referable in some instances to the Northern and in other instances to the Southern race. I have, therefore, in the ‘Fauna,’ fixed an arbitrary dividing-line as the latitude of Tavoy in Southern Tenasserim.
This Ground-Thrush keeps very much to dense forest for breeding purposes, though on more than one occasion its nest has been taken both in bamboo-jungle and in thick secondary growth. In forest it places its nest in almost any well-foliaged bush or small tree from about 3 to 30 feet from the ground but, generally, between 4 and 15 feet. Hutton says that in Mussoorie it builds principally “in the forky branches of lofty trees, such as oak and wild cherry.” In Assam, where this bird was very common, it had no preference, so far as I could see, for any particular kind of tree but, when building lower down, it certainly preferred tangles of Wild Raspberry or Blackberry vines to any other bush.
The nest, apparently, varies greatly in different parts of its area. In the Khasia and Cachar Hills and, again, in Lakhimpur, nests were all of the same type. Outwardly they were, in nine instances out of ten, made completely of moss ; in the tenth instance the moss was mixed with roots, grass and a few leaves, sometimes more, sometimes less. Inside this was a layer of well intertwisted coarse roots, leaves and grass-stems and inside this was the true lining of fine roots, rachides, rhizomorph or fine bents. Fine roots were the favourite linings, but the proportion of each material varied in each nest, sometimes one only being used. The mud or clay inner lining so frequently made by various species of Thrushes is certainly not always made by this bird, and of those found by myself or brought to me by natives (always with one bird or both) I do not think that more than one in five had a complete mud lining. A few other birds had incorporated a certain amount of clay or mud between the coarse and fine root-layers but even this was unusual. No one of my own or of Hume’s correspondents mentions a mud lining. Owing to the straggling nature of the external moss, the outer measurements of the diameter might be anything from 5 to 7.1/2 inches but, omitting the untidy ends, the average diameter would be nearly 6 inches, with a depth of fully 3 inches. The neat egg-cavity measures about 3 inches across by about 1.1/2 or rather more deep. Hodgson describes the nest as much like mine except for a lining of pine-needles. Hutton says that nests taken by him were externally “sometimes composed of coarse dry grasses, somewhat neatly woven on the sides but hanging down in long straggling ends from the bottom. Within this is a layer of green moss and another of fine dry woody stalks of small plants and a scanty lining at the bottom of fine roots.”
A nest taken by Mandelli in July was placed in a fork in a bamboo cluster at about 5 feet from the ground, “a loose, untidy nest, composed exteriorly of dead leaves, bamboo spathes, a few twigs and pieces of decayed bamboo, all wound together with vegetable fibre. The whole of the nest is composed of much the same materials, except that interiorly there are more chips of rotten bamboo and more vegetable fibre and very little dead leaf ; there is a mere pretence for a lining, a dozen or so very fine wire-like twigs being wound round at the bottom of the cavity.”
Another nest taken by Oates in Pegu was “made of roots and strips of soft bark, the ends of some of the latter hanging down a foot or more. The interior lined with moss and fem-roots.”
Oates does not give the elevation at which this nest was found but, apparently, it was in a ravine practically in the foot-hills. In Nepal Hodgson found it breeding at 4,000 to 5,000 feet, but Thompson says that in Kuman he “never found it except at 1,500 to 2,000 feet at most." Whymper, Rattray, Hutton and others found it about Murree, Mussoorie and Kuman at all heights up to 5,000 feet, whilst Stevens, Coltart and I obtained it breeding in Assam from the foot-hills up to 5,000 feet but, principally, between 2,000 and 3,500 feet. On the other hand I took one or two nests at 6,000 feet in the Barail Range.
The breeding season is principally May and June but. in Assam, I have taken eggs in the first week of April and as late as the 15th August, while I have one clutch from the Mackenzie collection taken at Dehra Dun on the 1st March, probably quite an abnormal date.
The bird sits close and will often allow one to watch it on the nest from quite near by. When leaving, it sometimes does so silently, whilst at other times it utters its beautiful loud whistle. Both sexes incubate and we trapped the male on the nest more often than the female. Both sexes also take an equal share in constructing the nest.
The eggs generally number four in a full clutch, sometimes three only, and occasionally five. They are like those of G. c. wardii but darker and better marked as a series. They also vary more, though this is doubtless due merely to my having had so great a number to choose from. I have seen many eggs much like rather pale eggs of the common Blackbird and others like erythristic eggs of the same bird. One clutch in my series of this type is so densely and closely marked that three eggs of the four look almost unicoloured buffy red. In great contrast to these are two clutches, laid by the same bird, which have the ground-colour a pale blue-green, unmarked except for dense caps of red-brown at the extreme larger ends. Another very extraordinary clutch of three stumpy, broad eggs has the ground a rather dark green well marked with dark brown, forming caps in two eggs at the large end. In this clutch there are numerous secondary blotches of dark brownish lavender, though secondary markings are rarely at all obvious in normally coloured eggs.
In shape the eggs vary from broad to long ovals, as a rule obtuse, but occasionally pointed at the smaller end. The texture is very fine and close, the surface hard and highly glossed, it being in this last respect that Geokichla eggs are most easily distinguished from those of other Thrushes.
One hundred eggs average 25.6 x 19.3 mm. : maxima 27.7 x 20.0 and 25.5 x 21.3 mm. ; minima 21.0 x 18.5 and 27.3 x 17.1 mm.
587. Geokichia citrina citrina
(587) Geokichla citrina citrina (Latham).