Transcriber's note: Text enclosed by underscores is in italics (_italics_). A single underscore introduces a subscript (CO_2), and a caret a superscript (B^1). Page numbers enclosed by curly braces (for example: {25}) have been incorporated to facilitate the use of the Alphabetical Index and other page references in the text. * * * * * THE CAMBRIDGE NATURAL HISTORY EDITED BY S. F. HARMER, Sc.D., F.R.S., Fellow of King's College, Cambridge; Superintendent of the University Museum of Zoology AND A. E. SHIPLEY, M.A., Fellow of Christ's College, Cambridge; University Lecturer on the Morphology of Invertebrates VOLUME IX [Illustration] [Illustration: NORTH POLAR CHART. Scale of Nature 1 to 47,830,000.] [Illustration: SOUTH POLAR CHART. Scale of Nature 1 to 95,660,000. (_Half the scale of North Polar Chart_)] BIRDS By A. H. EVANS, M.A., Clare College, Cambridge London MACMILLAN AND CO., LIMITED NEW YORK: THE MACMILLAN COMPANY 1899 _All rights reserved_ In sicco ludunt fulicae.–VIRGIL. Loons disport themselves on dry matters. {v}PREFACE In this volume of the "Cambridge Natural History" the author has attempted to meet a need which he believes to be somewhat widely felt. Recognising the fact that there is at the present time an abundance of popular, or only slightly scientific, works on Birds, some of which touch but superficially upon the individual species composing the various groups, as regards their plumage or habits, while others pay little or no attention to correctness of Classification, he has essayed the difficult and apparently unattempted task of including in some six hundred pages a short description of the majority of the forms in many of the Families, and of the most typical or important of the innumerable species included in the large Passerine Order. Prefixed to each group is a brief summary of the Structure and Habits; a few further particulars of the same nature being subsequently added where necessary, with a statement of the main Fossil forms as yet recorded. Thus it is hoped that the work may be of real use, not only to the tyro in Ornithology, but also to the traveller or resident in foreign parts interested in the subject, who, without time or opportunity for referring to the works of specialists, may yet need the aid of a concise account of the species likely to cross his path. An introductory chapter has been written, to meet the claims of the present day, on the external and to a limited extent on the internal structure of Birds, with short paragraphs on {vi}Classification, Geographical Distribution, and Migration, and a "Terminology" of the subject.