30 
Birds of Celebes: Falconidae. 
A fourth form, which we have termed A. virgatus gularis (T. & S.), is treated 
by Gurney as a distinct species — A. nisoides Blyth^). The means of distinguish- 
ing this form from the typical A. virgatus are not pointed out; Dr. R. B. Sharpe, 
however, considers it^) “a paler breasted form of A. virgatus with a shorter 
middle toe (28 mm as against 30.5 mm circa), the female being barred under- 
neath with brown, but not with rufous. It ranges from China down the Malay 
Peninsula, to Java and Timor, visiting these localities in winter” (k 5). Hume 
speaks of it as wanting the central gular stripe, but this does not always hold 
good, — at least for Chinese birds (k 7). Mr. Ogilvie Grant (m 5) has quite 
recently re-investigated this species, arriving at much the same result as 
Mr. Gurney, and holding A. gularis for a good species. Whether treated as 
a species or a subspecies does not lessen the difficulty of determining it, and 
Grant’s careful analysis seems to be applicable only to the old female. 
Mr. Hartert {m 6), with Gurney’s and Grant’s results before him, found 
much difficulty in determining Everett’s 3 examples from Djampea; the wing- 
formula and the markings on the breast did not correspond with Grant’s diagno- 
sis. When the migration of the subspecies is taken into consideration, it is 
probable rather that they were the tgpical A. virgatus than the East Asiatic form, 
gidaris, which in conformity with many other migrants from the north might be 
expected not to travel so far south. 
Dr. Sharpe’s A. rufotibialis may be distinguished from the others by its 
red thighs. 
Facts, as at present understood, appear to point to the circumstance that 
A. virgatus in the warmer parts of its distribution is stationary and has become 
modified there into several local races; in winter, however, these localities are 
invaded by quantities of individuals migrating southwards from China, Japan and 
probably elsewhere, where they have developed some racial differences, and 
which now become intermingled with the stationary races, and this circumstance 
makes a satisfactory understanding of the species hardly possible at the present 
day. In the spring the northern birds, apparently, separate themselves from 
their southern relations and proceed again to their breeding quarters in China 
and Japan. Had facts relating to these points been more plentiful when Gurney 
wrote, it is probable that he would have had reason to modify his views; facts, 
however, are still scanty. In North China, near Pekin, Abbe David says that 
the species arrives in spring in great numbers (12); about the lower Yangtse 
Basin Mr. F. W. Sty an marks it as a non-breeding species, which passes in 
migration, and mentions a pair of specimens taken at sea, between Shanghai 
and Nagasaki on 6*’^ May (I O); in South China, Foochow, Mr. De La Touche 
notes it as occurring in spring and autumn (j 6)\ in a note sent with a specimen 
from Kini Balu, Mr. M^hitehead speaks of it as being evidently a migrant 
1) Bly til’s name was published in 1847, Temminck and Schlegel’s Itaptores of tlie Fauna Jajionica, 
Aves, in 1845 (see Seebohm, B. Japan. Empire, 1890, 3); consequently these authors have the priority. 
2) Under the name A. stevensoni. 
