[[p. 1]] In the 'Muséum d'Histoire Naturelle des Pays-Bas,' the publication of which was commenced in 1862, Professor Schlegel has given a complete enumeration, often accompanied by descriptions and measurements, of all the specimens of Raptorial Birds contained in the Leyden Museum; and in his more recent work, 'Les Oiseaux des Indes Neerlandaises,' the third monograph¹, published in 1866, contains figures and descriptions of all the Falconidæ known to inhabit the Dutch East-Indian possessions. Later still, in the 'Proceedings of the Zoological Society of London' for 1867, is a paper by Dr. Kaup, "On the Nisi and Astures of the Indian Archipelago and of New Holland," undoubtedly the most difficult group of the Eastern Accipitres. It may fairly be asked, therefore, what novelty or interest the present Catalogue possesses, to render it worthy of publication in 'The Ibis.'

     My answer is, that Professor Schlegel's works above enumerated do not give a complete list of the Malayan Accipitres; for the first is a Museum Catalogue, the second a Colonial fauna; [[p. 2]] and, therefore, all species which do not exist in the Leyden Museum and which inhabit the Malay Archipelago, Northern Borneo, the Philippine Islands, Eastern New Guinea, and the islands extending thence to the Solomon Islands do not find a place in his works, although they undoubtedly form a part of the fauna of the Malay Archipelago. In the next place, I possess an extensive collection of this group formed by myself, comprising seventy-two out of the eighty-seven known species, and containing fine series of many of the species accurately labelled with locality and sex, with notes of the colours of the soft parts, which information I desire to make known in a connected form. Lastly, I differ in many points from both Prof. Schlegel and Dr. Kaup, and wish to explain the reasons why I differ from such eminent men.

     With the exception that Vultures are entirely absent, birds of prey are tolerably plentiful in the Archipelago, the total number of species being greater than those of India as restricted by Dr. Jerdon. This large number seems to be chiefly due to the breaking-up of the district into a vast number of islands, most of which were separated at a more remote epoch than that of the origin of many existing species, while some date from a high geological antiquity. Closely allied representative species, therefore, abound and swell the total amount, although in any one island or locality the number to be obtained is very small. The average number of Falconidæ found in an island is ten, of Strigidæ three. Java contains the largest number, possessing seventeen Hawks and eight Owls; Celebes comes next, with the same number of Hawks, but only five Owls; whereas in many districts of India, equal in extent to one of these islands, double this number of species would probably be obtained. In Ceylon Mr. Layard obtained twenty-three Hawks and seven Owls.

     Of the subfamilies, the true Hawks (Accipitrinæ) are the most abundant, numbering eighteen species; next come the Eagles (Aquilinæ) with sixteen species, the Kites (Milvinæ) with ten species, the Falcons (Falconinæ) with six species, and the Buzzards and Harriers (Buteoninæ) three species. Taking the groups of islands, the number of species diminishes pretty regularly from west to east. The Indo-Malay group (Malacca, [[p. 3]] Sumatra, Java, and Borneo) has thirty-eight species, the Philippines (no doubt imperfectly explored) ten, the Celebes group twenty-five, Moluccan group twenty-five, Timor group sixteen, Papuan group fourteen. Yet, owing to the larger number of islands, and the richness of Celebes as compared with the Philippines, the Austro-Malayan Region, on the east, possesses more species than the Indo-Malayan Region on the west, the former having fifty-eight, the latter forty-four species. The greater power of flight and more roaming habits of the diurnal as compared with the nocturnal birds of prey is well indicated by the fact that, while fourteen Falconidæ are common to the Indian and Australian regions of the Archipelago, only a single Owl has the same range--which is very suggestive of the natural character of these divisions. But few of the genera have a limited range. Hierax is strictly confined to the Indian region, and Spizaetus, Polioaetus, and Spilornis only pass beyond it into Celebes. This island exhibits its usual characteristic of a number of peculiar species, having (with the Sula Islands) eleven out of twenty-five which are found in no other island, an unusually large number in this wide-roaming group of birds. It also seems to have some power of conferring on its species a peculiar facies, similar to that which I have already noticed as occurring among the Papilionidæ (Trans. Linn. Soc. xxv. pp. 1-71). The Celebes varieties of Pernis cristatus and Spizaetus lanceolatus are coloured exactly alike, with a brown spotted band across the breast; and there is a similar style of coloration in Spilornis rufipectus and S. sulaensis, as well as in Baza magnirostris--all species peculiar to the Celebes group. Truly this island is a mystery hard to be understood--one of Nature's best riddles, which no man can find out!

     The classification of the Birds of Prey is so difficult that hardly two authors entirely agree upon it. As regards eastern genera, I think Dr. Jerdon, in his 'Birds of India,' has given the most natural arrangement; and I mainly follow him in the Falconidæ. It appears to me very unnatural to break up the large and powerful Eagles of the genera Circaetus, Spilornis, and Spizaëtus among the Buzzards and Hawks, as is done by Bonaparte and Prof. Schlegel, because we thereby destroy the [[p. 4]] distinctive features of those groups. Haliastur, however, seems much better placed among the Kites, with which it agrees in all essential characters. Schlegel places Aquila gurneyi as a Spizaetus among his Astures, and thus groups one of the most massive of the Eagles in the same subfamily with the most delicate little Sparrow-Hawks, such as Accipiter virgatus and A. rhodogaster.

     In the Owls the confusion and uncertainty is still greater, as will be seen by the following series of classifications . . .

[[Continues with the systematic list, not included here.]]

Note Appearing in the Original Work

1. Here quoted as "Valkv. Nederl. Ind." [[on p. 1]]