THE BIRDS OF AUSTRALIA. 
differentiated the Island form, and shall hereafter discuss fully the phases and 
distribution of this Hawk. From a criticism of the preceding notes it will 
easily be gathered that a peculiar and wonderful confusion is present, the 
variation in coloration being sometimes attributed to locality, others to 
sexual changes and sometimes to plumage conditions. 
The latest discussion of these birds appears in the Austr. Mus. Spec. 
Cat., No. 1, Vol. III., p. 278, June 26, 1912, where North deliberated thus : 
Whether there are one or two species of ‘ Brown ’ Hawk inhabiting 
Australia has long puzzled Ornithologists. Gould held the opinion that 
there were two species, one inhabiting the eastern, the other the western 
portion of the continent, inosculating in South Australia, and certainly 
specimens may be found agreeing very well with the two birds represented 
in his folio edition of the ‘ Birds of Australia ’ under the names of leracidea 
herigora and I. occidentalis. In the Catalogue of the Birds in the British Museum, 
Vol. I., p. 421, 1874, the late Dr. R. B. Sharpe shares Gould’s opinion, and 
in describing Hieracidea herigora remarks : ‘ The possession by the Museum 
of the original types of Hieracidea herigora, which were received from the 
Linnean Society, enables me to prove that the Hieracidea occidentalis of 
Gould is the true H. herigora. Both these species are very distinct, one from 
the other, in their adult and in their young plumages.’ . . . Dr. Sharpe 
proving that Gould’s H. occidentalis is the true H. herigora does away with 
the latter’s idea that one was representative of the other on opposite sides of 
the continent. In the ‘ Report of the Expedition to Bellenden-Ker Range ’ 
(p. 84, 1888), North-eastern Queensland, Mr. C. W. De Vis, M.A., remarks 
as follows under ‘ Birds of which specimens were obtained ’'—Hieracidea 
herigora Vigors and Horsfield, the Brown Hawk ; I find no constant difference 
of colouring, and no real distinction of locality between this and the so-called 
Eastern Brown Hawk, H. orientalis Schlegel. Birds with the colouring of 
each, and intermediate grades thereof, occur all over Queensland, and during 
the expedition were seen in company on the Mulgrave Plains ; the name 
H. orientalis, applied to our Queensland bird, should therefore be allowed to 
lapse.’ With a series of over thirty specimens from different parts of the 
continent and Tasmania, it would have much simplified my labours to have 
picked out examples agreeing with both of those described and figured forms, 
and referred to them as distinct species, but one cannot shut one’s eyes to the 
fact that intermediate forms occur containing the characters of both, and 
that light and dark forms occur in the same locality and may be met with 
together. There is, however, a greater preponderance of adult birds with 
the dark brown upper-parts with the feathers more or less margined with 
rufous, and the under-parts brown, with the throat, fore-neck and centre of 
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