Birds of Celebes: Bucerotidae. 
245 
sound of their wings, and on looking up, the birds are seen at such an im- 
mense height as to be only just distinguishable” (Str. F. VI, 113). 
Our artist, Brirno Geisler, has furnished us with the following valuable 
notes on Rhytidoceros'. “During my five-years’ travelling and collecting in Ceylon, 
Java, and German New Guinea I had the opportunity almost daily of observ- 
ing the flight of Hornhills, especially of Rhytidoceros in the last country. Al- 
though the bird is not common, its presence is perceived at long distances by 
its noisy flight. With powerful strokes they pass over the virgin- forest in the 
morning, usually in pairs, to certain fruit-trees, causing thereby a resounding 
noise which may be compared to the cutting of half-rotten wood with a big 
saw. On my frequent boat-trips to the Huon Gulf (New Guinea), when sailing 
not far from the coast, I was able to watch with ease the extended flight of 
this bird. Often there were a pair, more rarely a larger number (which then 
ahvays flew in single file at intervals of about 3 m) flying onward at a height 
of 100 — 200 m above the forest, and in spite of the great distance the beating 
of their wings could still be heard. In like manner, when on the mountains, 
enjoying the splendid view of the flat coast-land, I have seen the birds flying 
over wide stretches until they vanished in the distance from my keen sight. 
On several occasions I had the opportunity of watching the birds come over 
the fore-ljing hills, and then, describing a gveat bow from a height of about 
500 m, they settled upon the ti'ees on the coast. In settling they swoop down- 
wards on outstretched wings Avith a loud whizzing noise towards the bough in 
view, always, hoAvever, just before reaching it, they make a curve rising up to 
their seat, Avhen the male often gives utterance to a loud ‘go go — gagaga’ — as 
if of satisfaction. In the silent A'irgin-forest the noise of their flight brings to 
mind a locomotive-engine in quick motion. That the flight, although it cannot 
be called laborious, nevertheless taxes the birds’ energies very much, may be 
seen from the circumstance that after a long flight the bird ahvays settles with 
open bill and perceptibly out of breath. 
After the breeding-season an interesting spectacle is afforded by the assembly 
on the common roosting-tree. After sundoAvn all that have been scattered in 
the neighbourhood come singly, in pairs, or in groups, some approaching from 
a height, some bustling out of the thick forest to the tall, free-standing tree. 
Received with all sorts of ejaculations by those already arrived, the suitable 
sleeping-places are sought for amid frequent quarrels ; and, especially on moon- 
light nights, the company rarely ceases its somewhat noisy conversation.” 
From the observations of Davison and Geisler the flight of Rhytidoceros 
appears to be so superior to that of the other Ilornbills in the Fiast Indies that 
the Avonder is — not that Rhytidoceros ranges from N.W. India to the Solomon 
Islands without presenting neAV forms at every zoo-geographical step like other 
Hornhills, but that the ranges of its species are not even Avider than is the 
case. At all events there is good reason to belieA^e that the anomalous distribu- 
