The actual material which has been available for study consists of about 8,000 specimens of birds collected for the Bureau of Science, a few skins received in exchange from the Menage Collection, nearly 200 skins received from the United States National Museum, part in exchange and part as a loan, and a few small lots of skins from various sources. There are, however, some 150 species inhabiting the Philippines of which not a single specimen has been examined. Of some other species the available material is quite inadequate for complete descriptions; this is particularly true of the shore and water birds, most of which visit the Philippine Islands as migrants and can not be obtained here in breeding plumage. To meet these deficiencies a large number of descriptions have been taken from previous works, notably the Catalogue of Birds in the British Museum, Oates's Birds of British Burmah, and the four volumes on birds in the Fauna of British India, while a few have been taken from periodicals. All copied descriptions and parts of descriptions are inclosed in quotation marks followed by the authors' names; the exact reference in each case will be found in the synonymy of the species described. The quotations ending with "Bourns and Worcester MS." are taken from a manuscript prepared by Messrs. Frank S. Bourns and Dean C. Worcester and based upon the ornithological specimens collected by the Menage Expedition. This manuscript was intended for publication by the Minnesota Academy of Natural Sciences, but as that institution was unable to meet the necessary expense, the right to use the manuscript reverted to the authors who have permitted the publication of their notes in this Manual. The scientific name, an English name, and such native names as seem to be commonly used with some degree of accuracy are given for each species. The synonymy consists of references to original descriptions and to all works from which quotations are made; also to the following works when the species is given in them: Catalogue of Birds in the British Museum, Sharpe's Hand-List of the Genera and Species of Birds, Oates and Reid's Catalogue of Birds' Eggs in the British Museum, and McGregor and Worcester's Hand-List of Philippine Birds; other references are to plates or figures, records of rare species, important descriptions, notes on habits, or critical remarks. [2] The distribution of each species is given by islands, arranged alphabetically, with the names of collectors so far as these have been worked out from the available literature. Distribution outside of the Philippine Islands is given in a general way only. To the descriptions and measurements of the birds are added notes on habits, nests and eggs, abundance, etc. and in very many cases manuscript notes by Bourns and Worcester, giving information on habits, colors of soft parts, measurements, and validity of species.