(2220) Ardea imperialis*.
The Great White-bellied Heron.
Ardea imperialis Stuart Baker, Bull. B. O. C, xlix, p. 40 (1928) (Sikkim, Terai). Ardea insignis. Blanf. & Oates, iv. p. 383.
Vernacular names. None recorded.
Description. Above very like Ardea s. sumatrana but a purer, less dark, grey, with the white markings much less conspicuous, more grey, less white; the longest crest-feathers are more grey, less white, at the tips; lower breast, abdomen, flanks, axillaries, under wing-coverts and tail-coverts pure white; thigh-coverts white in front, grey behind.
Colours of soft parts. Iris ochreous-yellow ; loral skin, orbital skin and base of lower mandible greenish ; bill, upper mandible and inner margin of lower mandible blackish-slaty, tip of lower mandible underneath greenish-ochre, remaining portion mussel-grey; tarsus black with horny patches; claws black (Stevens).
Measurements. Wing 546 to 572 mm.; tail 199 to 211 mm,; tarsus 171 to 216 mm.; culmen 152 to 176 mm. There are, unfortunately, no sexed specimens available for measurement.
Young birds are dark brown above, the head and neck pale rufous-brown, streaked with whitish ; bill pale horny-brown.
Distribution. The Sikkim and Bhutan Terai to Assam and Northern Burma.
Nidification. Very little known. Eggs were sent to me from Sikkim said to have been of this bird; one addled egg was taken from two nests which contained two chicks each as well. These are very small and there may have been some mistake about them. Mr. W. S. Thorn found one nest of this species on the Temru River, Arrakan, in April, a huge nest of sticks placed high up in a tall tree. It contained four eggs which only differ from those of A. cinerea in their great size. In colour they are rather a pale washed-out sea-green, probably due to the fact that they were on the point of hatching. Two of these eggs measure 72.0 x 50.8 and 69.2 x 49.9 mm.
Habits. This fine Heron is an inhabitant of the swamps at the foot-hills of the Terai, or lower Himalayas, from Sikkim to Arrakan and ascends the hills to some five thousand feet and, possibly, a great deal higher. In Assam it was not very rare but haunted most inaccessible swamps and forests where there were no tracks and only difficult waterways. It certainly breeds in Sadiya, where a female I shot had large, soft-shelled eggs, one already in the oviduct, and it occurs there all along the foot-hills, either singly or in small flocks of four or five birds. Stevens met with it several times in the Winter on the streams debouching from the hills in North Lakhimpur, where it was always solitary and very wild and wary. The only stomach I have examined contained nothing but crayfish, one of these measuring fully eight inches. It has a very loud, deep croak and flies very fast, though with a deliberate slow flapping like that of other Herons.
* The name Ardea insignis Hodgson, Gray's Zool. Misc., p. 86 (1844) was a nomen nudum. It is there cited by Gray as a synonym of nobilis Blyth and therefore cannot be resuscitated by Hume for the present bird.