244 
Birds of Celebes: Bucerotidae. 
in Cv(iiiOTvliinus ccissidix. On the whole the wings suggest that Tdhytidocevos is 
more given to flying than the other genera. The following actual observations on 
the flight of the SucBvotidttc tend, to prove this. Prof. Newton in his ^^Dictionary 
of Birds” (1893, 435) states that Tickell in his manuscript “Birds of India” 
(in the library of the Zoological Society of London) “divides the hlornbills of 
that country into two genera only, Buceros and Aceros, remarking that the birds 
of the former fly by alternately flapping their wings and sailing, while those 
of the latter fly by regular flapping only”. Anthracoceros coronatus may be taken 
as typical of the former class, as is shown by Legge’s corresponding observa- 
tion: “when flying it proceeds with rather quick-flapping of the wings, and then 
sails along with .them outstretched, its long tail and motionless primaries giving 
it a singular aspect ... It usually does not take long flights; when it does the 
momentum of its huge bill and heavy neck are such as to cause it on alight- 
ing to topple forward before gaining its equilibrium” (B. Ceylon, 1880, 274). 
Davison observed the same mode of flight in Dichoceros hicornis (Str. F. VI, 99), 
so, also, Bourdillon in the same species (Str. F. IV, 387), in Anthracoceros 
conveoDus, here called Hydrocissa albirostris (t. c. p. 101), and in Ptilolaemus tickelU 
(p. 104). Berenicornis flaps regularly, but “keeps in small parties about the 
lower trees and undergrowth” (p. 106). 
As to Bhinoplacc vigil, Hartert (L f. O. 1889, 367, 368) remarks that it is 
“a bad flier, even worse than Buceros rhinoceros^^ . On Cranorrhinus corrugatus in 
E. Sumatra Dr. Hagen (T. Ned. Aardrijk. Genootschap 1890, (2) VII, 139) has 
published the following observations: it has “like all Hornbills a heavy clumsy 
flight, accompanied by a peculiar ringing whizzing noise. After about each 
kilometer of the way (they flew daily from the sea-side to their roosting-trees 
inland) they rested for some minutes on suitable tall tree-tops. The resting- 
places are flxed points, and, if they are not scared, the birds may be expected 
with tolerable certainty every evening at the appointed time”. It is thus seen 
that at least seven of the eleven genera of the Bucerotidae of the Indian countries 
and Great Sunda Islands have poor powers of flight: Anthracoceros, Buceros, 
Dichoceros, Ptilolaemus, Berenicornis, Bhinoplax, Cranorrhinus. 
The flight of the wide-spread Bhytidoceros appears to be in marked contrast 
to these. 
Davison writes of Bhytidoceros suhrujicollis and undulatus'. these species “are 
remarkably strong on the wing, and morning and evening, where they occur, 
numbers may he seen flying far overhead, sometimes at such a height that they 
look not bigger than Crows. The strokes of their wings are accompanied by 
a peculiar metallic or resonant swish^) which can be heard at an incredible 
distance. One is often made aware of these birds flying far overhead by the 
1) Bernstein (J. f. 0. 1861, 114) tries to explain the noisy flight by the movement of the air in the 
large air sacks, an explanation which appears to us very far-fetched; neither does Mr. 0. Glr ant’s 
explanation (C. B. XVII, 347 note) appear satisfactory. In our opinion the sound need not be explained in 
any other way than the noise caused by the flapping of the wing of many other large birds. 
