IN] RESPLENDENT TROGON OR QUEZAL (Pharmacnis mocinno) anterican j^atwe §>erie0 Group I. Natural History BIRDS OF THE WORLD A POPULAR ACCOUNT BY FRANK H. KNOWLTON, PH.D. United States National Museum Member of the American Ornithologists' Union, Washington Academy of Sciences Biological Society of Washington, Etc. WITH A CHAPTER ON THE ANATOMY OF BIRDS BY FREDERIC A. LUCAS Curator-in-Chief, Brooklyn Institute of Arts and Sciences THE WHOLE EDITED BY ROBERT RIDGWAY Curator of Birds, United States National Museum WITH 1 6 COLORED PLATES AND 236 ILLUSTRATIONS NEW YORK HENRY HOLT AND COMPANY 1909 BIOLOGY L1BRM*Y COPYRIGHT, 1909, BY HENRY HOLT AND COMPANY. Published March, 1909. Nortoooto J. S. Gushing Co. — Berwick & Smith Co. Norwood, Mass., U.S.A. EDITOR'S PREFACE THE Editor's share in the preparation of the present work consists of scarcely more than a careful reading and slight revision of the manu- script, the planning and general execution being entirely by the Author. So well, indeed, had Dr. Knowlton performed his task that there was need for scarcely more than perfunctory revision ; a slight correction, here and there, together with an occasional suggestion concerning a ques- tionable or doubtful statement, or one involving a difference of opinion between authorities, or that a particular conclusion be reconsidered, being practically the extent of the Editor's censorship. ROBERT RIDGWAY. WASHINGTON, D.C., April 15, 1907. 395389 PREFACE IT is perhaps hardly necessary to call attention to the great awakening of popular interest that has come about in recent years in relation to our birds, an interest that has been fostered not only by the admirable work of the Audubon Societies and the widespread nature teaching in the schools, but by the deeper, broader sentiment which is leading back to, and nearer to, Nature. The in- creasing number of people yearly turning back to the country, either for recrea- tion or permanent residence, has naturally stimulated a desire to know more intimately their surroundings, — the trees, the flowers, and the birds. Few of these people have either the inclination or the desire to become professional ornithologists, but they have wished to know at least the names and more inter- esting facts in the life histories of the birds they see constantly about them. To supply this demand for popular information, a large number of works have been written, and their extensive circulation proves that they have filled a real want. But most of these are more or less local in their scope, only a very few, for instance, treating of the birds of a whole country, and the time seems ripe for a work of moderate size, and in a single volume, that shall set forth in non-technical lan- guage the salient facts regarding the birds of the world. Such a work I have attempted to prepare. Following several preliminary chapters on the general appearance and struc- ture of birds, their migrations, distribution, classification, etc., every family has been passed in review and accorded approximately equal and even treat- ment. In many cases this amounts to a mention of all the known species of a family ; but in the larger families it has, of course, been possible to include only the more important or more interesting forms, though it is presumed that enough have been included to give a fairly comprehensive picture. The treatment of the so-called game birds, both aquatic and non-aquatic, has purposely been made very full, in the hope that it may also prove of interest to sportsmen as well as to the general reader. Technical language has been avoided, so far as pos- sible ; but in outlining the various groups a certain amount has been necessary, since the characters separating them are often relatively obscure, structural details. The main attention has been given to the birds as they appear in their homes — that is, their plumage, habits, songs, nests and eggs, food, etc. It is not intended for this book to be used for the identification of collections of bird skins, for the descriptions of size and plumage have only been made full enough to enable one to draw a fairly definite picture of the living bird. For the complete, technical descriptions the reader is referred to the numerous well-known treatises on the subject. VI Preface A work of the present scope is of necessity very largely a compilation, but I have sought in every instance to give the latest and most authentic information regarding the distribution and life history of the forms treated. That I have succeeded in all cases is too much to expect, for the literature of ornithology is now so very extensive and widely scattered that it is inevitable some things have been overlooked, though it is hoped that important omissions and errors are few. Among the hundreds of books, papers, and journals consulted, special mention should be made of Sharpe's " Hand-List of Birds," the " Catalogue of Birds in the British Museum," Newton's Dictionary of Birds, Dr. Stejneger's volume on Birds in the Standard Natural History, and Ridgway's " Birds of North and Middle America," without which it would have been impossible to write this book. In the matter of direct quotations from other authors, which have been freely made, the authority for the statement has been given, either in the introductory sentence or at its termination, but it has not been thought necessary in a popular work of this character to give in all cases the complete bibliographic citation. The professional ornithologist will be able, in most cases, to identify the publi- cation should further consultation be desired; wrhile the general reader, it was assumed, would hardly be interested in anything but the statement of fact. In order to facilitate the ready finding of the various forms mentioned in the text, a very complete index has been prepared, which includes not only all specific, generic, and higher group names, but every common name made use of. To further facilitate the location of the birds referred to, all common or popular names of birds have been capitalized and given first place, with the scientific names following in parentheses. The black-face headings at the beginning of each paragraph also serve to direct attention to any species sought. The chapter on the " Migration of Birds," in nearly its present form, appeared in the Popular Science Monthly, and is incorporated here with the permission of the editor of that journal. The selection of the illustrations for this book has given the author much concern. To keep the book light, it is essential to avoid as far as practicable the use of the coated paper needed for half-tones. This necessitated securing for the text, wood and line cuts from miscellaneous sources not always equally modern or artistic. While a freer use of half-tones would have permitted the utilization of more modern photographs, it would have made the book almost fatally heavy; but it is hoped that the figures finally selected may serve the purpose of conveying a fair idea of the forms depicted. In the preparation of the originals of the colored plates, the author has been fortunate in securing the services of the talented artist, Miss Mary Mason Mitchell of Washington. Not only are the birds themselves accurately and artistically portrayed, but the setting for each has been worked out with a minute- ness and correctness of detail rarely exhibited. In the preparation of this work I have received the greatest assistance from Dr. Charles W. Richmond, Acting Curator of Birds in the United States National Museum, who has not only read all of the manuscript and proofs, and suggested Preface vn many corrections, changes, and additions which have materially increased its value, but has permitted me every opportunity of examining the collection of birds in his charge. Mr. Frederic A. Lucas, Head Curator of the Brooklyn Museum of Arts and Sciences, has read portions of the manuscript, and made valuable suggestions, and has also written the chapter on the "Anatomy of Birds." Mr. J. H. Riley, of the United States National Museum, has called my attention to a number of things that might otherwise have been overlooked, and Dr. C. William Beebe, of the New York Zoological Garden, has been of great assistance in securing and reproducing the figures. To Mr. Robert Ridgway, Curator of Birds in the United States National Museum, I was indebted for many valuable suggestions, especially in regard to classification, before it was known that he was to edit the book. Since the completion of the work he has read the manu- script and suggested certain changes and slight revisions of statement, the extent of his work being indicated in the Editor's Preface which precedes. To these and all others who have assisted in the preparation of the book, I make grateful acknowledgment. Following are the sources for most of the figures used, acknowledgment for which is hereby made : — American Museum of Natural History: 37, 39, 40, 44, 47, 55, 96, 108, 134, 135. Baird, Brewer, and Ridgway, North American Birds — Water Birds: 31, 32, 34, 36, 38, 41, 42, 43, 45, 52» 53, 57, 58> 59, 6o> 62, 63, 64, 65, 66, 67, 68, 107, 117, 119, 121, 123, 125, 126, 133, 136. Blanford, Birds of British India: 176, 193. Brehm: 27, 56, 80, 87, 109, 114, 182, 183, 184, 200, 214, 224. Buller, Birds of New Zealand: 179, 221. Catalogue, Birds in the British Museum: 173. Challenger Expedition : 30, 166. Dresser, Birds of Europe : 99, 194. Fisher, Hawks and Owls of the United States: 74, 76, 81, 159, 162. Milne-Edwards & Grandidier: Histoire Physique, Naturelle et Politique de Madagascar, vol. xii; Histoire Naturelle des Oiseaux: 49, 54, 84, 93, 132, 138, 150, 156, 158, 178, 191, 195, 202, 203, 204, 206, 209. Newton's Dictionary of Birds: 72. North, Nests and Eggs of Birds of Australia and Tasmania: 212. Packard's Zoology: 189. Proceedings Zoological Society, London: in, 113. Salvin and Godman, Biologia Americana: 90, 180, 186, 187. Schlegel, De Diergaarden von vroegeren en lateru t ijd ing de Diergaarde Kon. Zool. te Amster- dam: 71, 92, 100, 102, 106, 109, 115, 118, 120, 127, 128, 129, 130, 144, 145, 149, 155, 161, 163, 164, 169, 171, 172, 182. Sclater and Hudson, Argentine Ornithology: 185. The Auk: 91, 207. The Ibis: 181. Transactions Zoological Society, London: 23, 24, 25, 26, 29, 33, 48, 85, 88, 138. U. S. Department of Agriculture: 210, 211, 218, 219, 231, 232, 320. U. S. National Museum: 3, 4, 28, 103 a. F. H. K. UNITED STATES NATIONAL MUSEUM, January i, 1909. CONTENTS CHAPTER I PAGE INTRODUCTION i Definition of a Bird, I. — Temperature, 3. — Definition of various forms of feathers, 3. — Colors of feathers, 4. — Pterylosis, 6. — Moult or renewal of feather covering, 8. — Nests and eggs of Birds, 10. — Theory of Birds' nests, n. CHAPTER II THE ANATOMY OF BIRDS. By FREDERIC A. LUCAS 13 CHAPTER III GEOGRAPHICAL DISTRIBUTION OF BIRDS 26 CHAPTER IV THK MIGRATIONS OF BIRDS 33 CHAPTER V THE CLASSIFICATION OF BIRDS 45 CHAPTER VI THE ARCH/EOPTERYX, OR LIZARD-TAILED BIRD. Order Archceornithiformes . 53 CHAPTER VII THE AMERICAN TOOTHED-BIRDS. Orders Hesperornithiformes and Ichtkyornithiformes 56 CHAPTER VIII THE OSTRICHES. Order Struthioniformes 6 1 CHAPTER IX THE RHEAS. Order Rheiformes 67 CHAPTER X THE EMEUS AND CASSOWARIES. Order Casuariifor mes 70 CHAPTER XI THE TINAMOUS. Order Crypturiformes 78 x Contents CHAPTER XII PAGE THE MOAS. Order Dinornithiformes 81 1 CHAPTER XIII THE ELEPHANT-BIRDS. Order JEpyornithiformes 85 CHAPTER XIV THE KIWIS, OR WINGLESS BIRDS OF NEW ZEALAND. Order Apterygiformes . 87 CHAPTER XV THE PENGUINS. Order Sphenisciformes 92 CHAPTER XVI THE LOONS AND GREBES. Order Colymbi formes 100 CHAPTER XVII THE ALBATROSSES AND PETRELS. Order Procellariiformcs 107 CHAPTER XVIII THE STORK-LIKE BIRDS. Order Ciconiiformes 121 The Tropic-birds, 122. — The Pelicans, 124. — The Cormorants, 127. — The Anhingas, or Darters, 131. — The Gannets, 133. — The Frigate-birds, 136. — The Herons, 139. — The Boat-bills, 147. — The Shoe-bill, 149. — The Hammer-head, or Umbrette, 151. — The Storks, 153. — The Ibises, 160. — The Spoon-bills, 163. — The Flamingos, 165. CHAPTER XIX THE GOOSE-LIKE BIRDS. Order Anseri formes 169 The Screamers, 169. — The Swans, Geese, Ducks, and Mergansers, 172. CHAPTER XX THE FALCON-LIKE BIRDS. Order Falconiformes 202 The American Vultures, 203. — The Secretary-bird, 209. — The Falcons, Goshawks, Cara- caras, and allies, 212. — The Kites, Buzzards, Eagles, Hawks, and allies, 226. CHAPTER XXI THE FOWL-LIKE BIRDS. Order Galliformes 263 The Madagascar Mesite, 263. — Hemipodes, or Bustard Quails, 265. — The Megapodes, 268. — The Curassows and Guans, 271. — The True Game Birds: Turkeys, Partridges, Quails, Pheasants, etc., 276. — The Hoactzin, 317. CHAPTER XXII THE CRANE-LIKE BIRDS. Order Gruiformes 320 The Rails, Gallinules, and Coots, 320. — The Cranes, Courlans, and Trumpeters, 327. — The Cariamas, 339. — The Bustards, 340. — The Kagu, 345. — The Sun-Bitterns, 347. — The Fin- feet, 348. Contents xi CHAPTER XXIII PAGE THE PLOVER-LIKE BIRDS. Order Charadriiformes 350 Laro-Limicolae: The Plovers, Snipes, Curlews, etc., 351. — The Sheath-bills, 374. — The Crab-Plovers, 375. — The Pratincoles and Coursers, 376. — The Seed-Snipes, 379. — The Thick-knees, 380. — The Jacanas, 382. — The Gull Tribe, 386. —The Auks, Puffins, and Murres, 396. — Pteroclo-Columbae : The Sand Grouse, 405. — The Dodo and Solitaire, 409. — The True Pigeons, 413. CHAPTER XXIV THE CUCKOO-LIKE BIRDS. Order Cziculiformes 441 The Cuckoos, 442. — The Plantain-eaters, 451. — The Parrots, 454. CHAPTER XXV THE ROLLER-LIKE BIRDS. Order Coraciiformes 480 The Rollers, 480. — The Motmots and Todies, 485. — The Kingfishers, 489. — The Bee- eaters, 496. — The Hornbills, 501. — The Hoopoes, 508. — The Owls, 511. — The Oil-bird, 541. — The Frogmouths, 542. — The Goatsuckers, or Nightjars, 546. — The Hummingbirds, 553. — The Swifts, 561. — The Colics, 569. — The Trogons, 571. — The Jacamars and Puff- birds, 576. — The Barbets and Honey-guides, 580. — The Toucans, 583. — The Woodpeckers and Wrynecks, 586. CHAPTER XXVI THE SPARROW-LIKE BIRDS. Order Passeriformes 603 Eurybemidae : The Broad-bills, 605. — Clamatores: The Pittas, 609. — The Asities, 611. — The Rifleman and New Zealand Wrens, 611. — The Sharp-bills, 615. — The Tyrant-birds, 615. — The Manakins, 621. — The Chatterers, 623. — The Plant Cutters, 629. — The Wood Hewers, 631. — The Oven-birds and allies, 633. — The Ant-birds, 635. — The Ant-Pipits, 637. — The Tapacolas, 638. — Pseudoscines : The Lyre-birds, 640. — The Scrub-birds, 643. — Oscines: The Larks, 644. — The Wagtails and Pipits, 651. — The Fork-tails, 656. — The Babbling Thrushes, 657. — The Bulbuls, 662. — The Flycatchers, 665. — The Thrushes, 671. — The Wren-Thrushes, 686. — The Mockingbirds, 686. — The Dippers, 690. — The Wrens, 694. — The Wren-Tits, 697. — The Old World Warblers, 698. — The Kinglets, 704.— The Swallows, 705. — The Cuckoo-Shrikes, 713. — The Drongos, 717. — The Wax wings, 719. — The Silky Flycatchers, 720. — The Palm Chats, 721. — The Wood Swallows, 723. — The Vanga-Shrikes, 724. — The Shrikes, 724. — The Wood Shrikes, 734. — The Helmet-birds, 737. — The Vireos, 739. — The Nuthatches, 742. — The Coral-billed Nuthatch, 745. — The Titmice and Chickadees, 747. — The Orioles, 753. — The Bower-birds, 755. — Birds-of- Para- dise, 759. — The Crows and Jays, 770. — The Starlings, 785. — The Glossy Starlings and Grackles, 790. — The Honeyeaters, 792. — The White-eyes, 797. — The Sun-birds, 799. — The Flower-peckers, 802. — The Creepers, 805. — The Honey Creepers, 807. — The Hawai- ian Honey Creepers, 809. — The Wood Warblers, 81 1. — The Tanagers, 816. — The Weaver- birds, 819. — TheTroupials, 824. — The Swallow-Tanagers, 830. — The Plush-capped Finches, 830. — The Finches and Sparrows, 831. INDEX . . 847 COLORED PLATES RESPLENDENT TROGON, OR QUEZAL, Pharomacrus mocinno . . . Frontispiece PAGE AGAMI HERON, Agamia agami 144 ROSEATE SPOON-BILL, Ajaja ajaja 164 MANDARIN DUCK, Aix galericulata . 190 LADY AMHERST PHEASANT, Chrysolophus amherstite 312 TUFTED PUFFIN, Lunda cirrhata 398 GREAT CROWNED PIGEON, Goura coronata 438 HAWK-PARROT, Deroptyus acdpitrinus 472 RED-BACKED MOTMOT, Eumomota superdliaris 488 RACKET-TAILED KINGFISHER, Tanysiptera nais 496 FIERY TOPAZ HUMMINGBIRD, Topaza pyra 558 ELEGANT PITTA, Eucichla boschi 610 LESSER BIRD-OF-PARADISE, Paradisea minor 766 COLLIE'S MAGPIE-JAY, Calocitta colliei 78° RED WARBLER, Ergaticics ruber 816 CENTRAL AMERICAN TANAGER, Chlorochrysa nitidissima 818 Xlll CHAPTER I INTRODUCTION EFINITION of a Bird. — Strange as it may seem, the old proverb that "A bird is known by its feathers," finds such exemplification in the science of to-day that it has actually become the scientific definition of the Class. It was formerly supposed that birds possessed a number of peculiar features, but, says Mr. Ridgway, "the most recent investiga- tions of comparative anatomists have gradually eliminated the supposed exclu- sive characters of birds, as a class of the Animal Kingdom, until only the single one mentioned above, the possession of feathers, remains." As Dr. Stejneger very aptly expresses it, " No bird is without feathers, and no animal is invested with feathers except the bird." From the fact that in most systematic arrangements of the Animal Kingdom the Class embracing the birds is usually made to precede the mammals, it might be supposed that the birds were more or less closely related to them. As a matter of fact this is not so, for, according to Beddard, beyond the circumstance of " warmbloodedness and resemblance of some of the more simple forms of feathers to hairs, there is nothing to be said in behalf of a kinship between birds and mam- mals." In some ways birds are undoubtedly the highest of the vertebrate animals. Their body temperature, higher than that of any other animals, is one index of their intense activity; their skeleton is perhaps more modified from the general type than that of mammals, their "arrangements for locomotion, breathing, and nutrition are certainly not less perfect," and it is, in fact, "only when we emphasize the development of the nervous system and the closeness of connection between mother and offspring, that the mammals are seen to have a right to their preeminence over birds." It has long been settled with definiteness that the Class of birds is very closely allied to the Class of reptiles ; for even at the present time, that is among living birds and reptiles, there are numerous structural points in common. It is, of course, perfectly easy to distinguish between a bird and a reptile as each exists at present, the most obvious difference being the warm blood and outer covering of feathers in the bird, and the cold blood and usually scaly covering among reptiles. On account of unfortunate breaks or gaps in the paleontological record, we are, with the exception of the evidence afforded by Archaeopteryx, in ignorance of the precise steps in the transition from one Class to the other, and may always remain so, but as was long ago pointed out by Huxley, Cope, Marsh, and others, it is probably in the group of extinct dinosaurs that we must look for evidences of 2 Introduction this affinity. This large reptilian group embraces a number of forms, particu- larly those of carnivorous habits, that without doubt regularly progressed in a bipedal manner, and it was from the obvious similarity between these and the birds that Huxley concluded that "there could be no doubt that the hind quarters of the Dinosauria woriderfully approached that of birds in their general structure, therefore, that these extinct reptiles were more closely allied to birds than any which have lived." Other anatomists have held that these resemblances in structure are simply adaptive, and came to be evolved in the dinosaurs from community of habit with birds, but very recently Professor H. F. Osborn has reexamined the evidence and has detected a number of additional points of agree- ment in skeletal characters, and concludes that this hypothesis is not to be dis- carded, but is to be "very seriously considered" in connection with the origin of birds. Still more recently (1905) Professor E. Ray Lankester, director of the British Museum [Natural History], says: "The reptiles which come nearest to them in structure are the Dinosaurs, especially these Dinosaurs (like Iguanodon) which walked on their hind legs and had only three toes to the foot." In any event it seems safe to assume that if not more intimately related, the dinosaurs and birds must at least have had a common ancestor. Within the past few months, Mr. W. P. Pycraft, the eminent avian anatomist of the British Museum, has presented an interesting speculation regarding the probable ap- pearance of the ancestral or incipient birds anterior to Archaeopteryx. He says: "From what we know of other types of vertebrates we may safely assume that these ancestral birds were of small size, and were probably also arboreal. And from the unmistakable signs of the shortening of the body in modern birds, the trunk was also relatively longer, as it certainly was in Archse- opteryx. From these two inferences we conclude, with some degree of proba- bility, that these creatures, these 'birds in the making,' had substituted leaping for climbing about the trees. And from this there was but a short passage to leaping from tree to tree. In these movements we may reasonably suppose that the fore limbs were used for grasping at the end of the leap. The use of the fore limb for this work would naturally throw more work upon the inner digits — 1-3 — so that the work of selection would rapidly tend to the increased develop- ment of these, and the gradual decrease of the two outer and now useless members. Correlated with this trend in the evolution, the axillary membrane — the skin between the inner border of the arm and the body — became drawn out into a fold, while a similar fold came to extend from the shoulder to the wrist, as the fore limb, in adaptation to this new function, became more and more flexed. While the fingers, upon which safety now depended, were increasing in length, and growing more and more efficient, they were, at the same time, losing the power of lateral extension, and becoming more and more flexed upon the fore arm. And the growth in this direction was probably accompanied by the develop- ment of connective tissue and membrane along the hinder, post-axial border of the whole limb, tending to increase the breadth of the limb when extended preparatory to parachuting through space from one tree to another, the long claws being used to effect a hold at the end of the leap. The hind limbs, though Temperature of Birds 3 to a less extent, were also affected by the leaping motion, resulting in the reduc- tion of the toes to four, and the lengthening, and approximation of the meta- tarsals 2-4 to form a 'cannon' bone. "The body clothing at this time was probably scale-like, the scales being of relatively large size and probably having a median ridge, or keel, recalling the keeled scales of many living reptiles. Those covering the incipient wing, grow- ing longer, would still retain their overlapping arrangement, and hence those along the hinder border of the wing would, in their arrangement, simulate in appearance and function the quill feathers of their later descendants. As by selection their length increased, so also they probably became fimbriated, and more and more efficient in carrying the body through space." Temperature. — It is a generally recognized fact that the temperature of birds is normally very high, but, strange enough, exact data on the subject are not extensive. Recently Mr. A. Southerland undertook to ascertain the tempera- ture of certain " Ratite " birds, and one of the most interesting incidental facts brought out is the demonstration of a progressive increase from the lower to the higher birds ; that is, the forms of birds that are regarded as the lowest in the scale exhibit the lowest normal temperature, while between these and the more active and highly organized there is almost every gradation. This condition also pre- vails at least to some extent among mammals. The Apteryx or Wingless Birds of New Zealand exhibit the lowest temperature thus far recorded among birds, the average of three individuals belonging to two species being 37. 9° C. (100.2° F.). Next to the Apteryx come the Emeus, Cassowaries, and Penguins, with an average normal temperature of 39° C. (102.2° F.), while theTinamous examined showed a range from 39.2° C. to 41.3° C., or an average of 40.6° C. (105° F.), "which brings them up to the lower limit of the range of temperature usual for ducks, gpume birds," etc. The common fowls when lifted quietly off their perches at night have a temperature of 40.6° C. (105° F.), but when lifted by day from nests whereon they are brooding, their temperature averages 41. 7° C. (107° F.). From these birds there is another decided advance when we come to the great groups of small and excessively active birds such as Sparrows, Warblers, etc., their temperature ranging from 42° C. (107.6° F.) to 44° C. (111.2° F.), with an average of perhaps 109° F., or fully ten degrees above that of man. Feathers. — We may now advert to a consideration of the peculiar outer covering of birds; namely, the feathers. A normal feather (Fig. i) consists of a hollow transparent basal portion called the barrel, or calamus, continuous with which is the main shaft, or rachis, which is opaque, roughly quadrangular in cross-section, and filled with a pithy substance. The rachis is furrowed along its inner surface ; that is, on the side next the body of the bird. From the rachis above the barrel arise a " series of lateral branches, the barbs or rami, which in turn give rise to the barbules, and these to minute, often hooked processes, the barbicels" (Fig. 2). It is by the hooking together of these processes that the web is produced and strength is given it to resist or act upon the air. Springing from the under side of the feather, in many cases, at the juncture of the barrel with the web-bearing portion, is a secondary feather, or aftershaft, as it is called. Introduction In some birds, as in the Cassowaries and Emeus, the aftershaft is as large as, or larger than, the main portion of the feather, while in others it is greatly reduced or even absent. Not all feathers exhibit as complicated a structure as that above described. In many cases the feather is much reduced, as for example in the wing-quill of the Cassowary, which consists merely of the stiff, naked stem or rachis. The so-called filo plume is another modification of the typical feather, a good example of which may be seen on the body of a common fowl after the removal of the outer or contour feathers It is to all appearances a slender hair, but in reality it is a degenerate feather which has a very short barrel and a thin, hair-like rachis with few or no branches. Usually the filoplumes are entirely concealed by the contour feathers, although in some birds, as the Cormorants, they form tufts of plumes on the sides and back of the neck which project beyond the outer (contour) feathers. A further modifica- tion is found in the so-called "downs," these being feathers in which there is no rachis, the long fluffy branches all arising at the top of the barrel: they are concealed by the contour feathers. In certain birds, such, for example, as the Herons, Bitterns, some Hawks, Par- rots, Tinamous, etc., the downs are aggregated in special patches, called " powder-downs," in which the ends are continually breaking off into fine, dust- like particles. In the Herons, for in- stance, the powder-downs form enormous patches, — a pair on the breast and a pair over the thighs. Their nature is not well understood, although their presence may constitute a well-marked character for descriptive purposes. Colors of Feathers. — The colors of feathers, or their apparent colors, constitute an exceedingly interesting phase of this subject. In accordance with the latest authorities the colors of feathers may be conveniently classed under three heads. The first of these, and the most general, are called chemical or absorption colors, since they are due to the presence of distinct coloring-matter. This coloring- matter may be in the form of a pigment, or may be a coloring solution, which is distributed in or among the cells composing the various parts of the feathers. Under this category come black, red, and brown, mostly the orange and yellow, but rarely green, and never blue. These colors may be recognized by the fact that they do not change under any condition of illumination or the position of the eye viewing them, and certain of them, as black, red, and yellow, may be separated in a practically pure state by well-known methods of chemical manipulation. One of the most interesting, known as turacin, is found in the red feathers of the Plantain Eaters (Musophagida). It contains the same chemical elements as FIG. i. — Feather and aftershaft. Colors of Feathers those found in black feathers, but with the addition of from 5 to 8 per cent of copper, and these birds lose their red color when washed by the rain-, but regain it again when dry. The water in which they bathe is said to become reddish. The second kind of coloring results from the combination of a pigment with certain structural peculiarities, such as ridges and furrows, in the surface of the feather itself. Such colors as violet and blue, usually green and sometimes yellow, belong under this heading. In transmitted light feathers with these colors show only the color of the pigment. "For instance, the deep green or blue feathers of a Parrot will thus appear only gray or yellowish. The same happens when their polished surface is scratched or crushed ; the blue color instantly disappears, showing only the blackish underlying pigment, or yellow pigment in green feathers. When thor- oughly wetted in a bath the feathers of the back of an Amazon Parrot appear brown without a trace of green." — NEWTON. The third form of coloring, or apparent coloring, includes the exquisitely beautiful prismatic or metallic colors, such as those found in Hummingbirds, the Birds of Paradise, Peacocks, Doves or Pigeons, Starlings, Grackles, and very many other birds. The manner in which these effects are produced has given rise to much spec- ulation, and an extensive literature exists upon the subject, but even now the ques- tion can hardly be considered as definitely settled. The commonly accepted hypothesis is that . metallic colors are due entirely to the structure of the surface of certain parts of the feathers, such as striae, ridges, knobs, or pits, in combination often with extremely thin, transparent, colorless layers, these elements, it is asserted, acting as prisms and changing the color as the direction of the light and the position of the eye change. Recently Dr. R. M. Strong appears to have demonstrated that the above explanation fails to meet certain of the physical requirements of the case. In investigating the metallic colors of feathers from the sides of the neck of the domestic Pigeon, he failed to find striae or other inequalities on the outer surface of the barbules that were sufficiently numerous or uniform enough to produce the observed colors by diffraction, but he did find that the barbules within the metallic area were strik- ingly different from those outside it. Instead of lying vertically, as in the non- metallic areas, they are turned so that one side faces upward, thus giving a much greater reflecting surface. The dorsal face of these barbules is provided with an outer transparent wall which encloses cell-cavities filled with pigment, this coloring-matter being in the form of spherical granules in the metallic-colored barbules, whereas in the non-metallic-colored areas the granules are of the FIG. 2. — Two enlarged barbs of a feather, showing interlocking barbules and barbicels. 6 Introduction typical rod shape. He therefore concludes that "the metallic colors of these feathers are probably thin-plate interference colors or Newton's-rings effects, which are produced when spherical pigment granules come in contact with the outer transparent layer." The whole subject of coloration is treated at length by Newton in his " Dictionary of Birds," to which the reader is referred for fuller information. /Pterylosis. — It is a fact of common observation that in the hair covering of ^certain mammals, such as the horse, dog, cat, etc., the hairs are set as closely together as practically possible, forming a continuous covering. From the fact that in most birds, the entire body, except the beak and feet, is ordinarily covered by the feathers, it might be inferred that they are as continuously and evenly dis- FIGS. 3 and 4. — Pterylosis of Nighthawk. tributed over the body as are the hairs of mammals. This condition is far from true, however, as may be readily demonstrated by plucking the feathers from the body of any common bird, when it will be seen that the feathers ar<* only borne on certain definite areas or tracts, being ordinarily spread out so as to more or less completely cover the body. This peculiarity was noticed and especially empha- sized by Nitzsch, a celebrated German ornithologist, some sixty years ago. The feather areas he called " feather-forests," or pteryla, and the naked spaces apteria, from the Greek, signifying " without feathers." The description of the feather distribution in birds is called pterylosis or pterylography. The most important of the feather tracts are as follows: A spinal tract which runs down the backbone from the nape of the neck to the tail; a ventral tract, which "runs from the throat down the front of the neck, and dividing at its base, passes down on each side of the breast and abdomen to the inner side of the thighs quite to the end of the body"; the humeral tracts, a pair of tracts running across the upper Development of Pterylosis 7 arm, and forming what are called the scapulars; and the femoral tracts, a pair of tracts over the thighs. The pterylosis of the Nighthawk is shown in the accompanying figures (Figs. 3, 4). It has been found that the extent and distribution of the feather tracts and bare spaces are relatively very uniform for certain groups of birds, so uniform, in fact, that pterylosis was made the basis of an elaborate scheme of classification^ of birds by Nitzsch. That it is of diagnostic value in many cases cannot be denied, but when relied upon too implicitly it not infrequently leads to what are obviously unnatural assemblages. Further than this we are still in ignorance of the pterylography of a vast number of birds, for the subject has been largely neglected since the time of Nitzsch. When a larger array of facts is at hand it may be possible to extend its usefulness. The only birds at present known to have a continuous feather covering are the Penguins and Screamers, although formerly the Ostriches and their immediate allies were supposed to fall within this category. Apteria have long been known to occur in the embryos of certain "Ratites," as the Ostrich, Rhea, and Apteryx, but recently Pycraft has shown that small but relatively important apteria occur in the adults of all members of this group. Development of Pterylosis. — In a communication before the American Ornithologists' Union, November 18, 1903, Dr. Hubert Lyman Clark presented some important results of his examination into the development of the pterylosis. The material studied consisted of 54 embryos belonging mainly to different groups of birds such as Herons, Rails, Sparrows, Woodpeckers, Hummingbirds, and Swallows. In every instance he was able to distinguish the outlines of certain of the principal feather tracts before the body of the bird had assumed very definite form, — for example, before the shape of the head could be distinctly made out. In all cases examined the caudal tract was the first to be outlined, and further the middle pair of tail-feathers was uniformly the first to appear. At this stage in the development of the embryo the tail was disproportionately long and had the feathers disposed along it in pairs, a condition very suggestive at least of the tail of Archseopteryx. As a further interesting result it was shown that in the specimens studied the secondaries of the wing were the first to appear, thus confirming the result of Pycraft's studies on the development of the Mound- Builders (Megapodidce). The primaries were found to be developed distally; that is, from the angle of the wing toward the tip. It would seem that characters as deep seated as these have been shown to be must have an important bearing on the taxonomy of birds when we are in possession of a sufficient body of facts to permit of generalization, but, as Dr. Clark pointed out, we do not yet know the complete history of the development of the pterylosis of a single species of bird. The causes which have led to the development of feather tracts and conse- quent bare spaces are not well understood. The suggestion that it is simply another example of nature's economy of material seems hardly an adequate one ; the explanation advocated by Mr. F. A. Lucas, namely, that it is a case of adapta- tion, being decidedly more logical. On this point Mr. Lucas says : "The pterylosis of all birds is more or less adaptive, having some direct relation to their habits, 8 Introduction and this adaptation is well shown in Hummingbirds. The bare tracts on the nape and along the throat allow the neck to readily lie against the middle of the back, or to bend downward over the points of the breast-bone, while the bare spaces under the wings and along the sides of the body permit the wings to be easily and closely applied to the body, the sides conforming almost exactly to the curve of the edge of the folded wing. The large bare space on the under side, found in nearly all birds save the water fowl, is merely to allow the warmth of 47481 v ...<;:;-'::::'" ---. 10 24 23 FIG. 5. — Topography of a bird. (From Coues's " Key.") i, forehead (frons); 2, lore; 3, circumocular region; 4, crown (vertex); 5, eye; 6, hind head (occiput}; 7, nape (nucha); 8, hind neck (cervix); 9, side of neck; 10, interscapular region; n, dorsum, or back proper, including 10; 12, nolaum, or upper part of body proper, including 10, n, and 13; 13, rump (vropygium); 14, upper tail-coverts; 15, tail; 16, under tail-coverts; 17, tarsus; 1 8, abdomen; 19, hind toe (hallux); 20, gastrceum, including 18 and 24; 21, outer or fourth toe; 22, middle or third toe; 23, side of the body; 24, breast (pectus); 25, primaries; 26, secondaries; 27, tertiaries, nos. 25, 26, 27, are all remiges; 28, primary coverts; 29, alula, or bastard wing; 30, greater coverts; 31, median coverts; 32, lesser coverts; 33, the " throat," including 34, 37, and 38; 34, jugulum, or lower throat; 35. auriculars; 36, malar region; 37, gula, or middle throat; 38, mentum, or chin; 39, angle of commissure, or corner of mouth; 40, ramus of under mandible; 41, side of under mandible; 42, gonys; 43, apex, or tip of bill; 44, lomia, or cutting edges of the bill; 45, culmen, or ridge of upper mandible, corresponding to gonys; 46, side of upper mandible; 47, nostril; 48, passes across the bill a little in front of its face. the body to be directly applied to the eggs during incubation, and in birds like Ducks and Penguins (also Auks), which are densely or completely feathered beneath, a bare space is present during the breeding season." Renewal of Feather Covering. — Although a considerable proportion of the feathers in flying birds are relatively strong, especially those of the wings and tail, the more or less active life of their owner results sooner or later in the wear and often injury of all feathers. The chief of the destructive influences to which feathers are subjected are abrasion and fading, the one a mechanical disintegra- tion, and the other a chemical decoloration. Besides these there are other minor factors, such as " the age of a feather, its position, its structure, its color, and the Renewal of Feather Covering o habits of the bird." It is thus evident that if a bird were provided with only a single set of feathers, they would ultimately become so worn and frayed as to be useless, either as a covering for the body or for flight. By a wise provision of nature, the entire feathering is renewed at periodic intervals. This renewal known as the moult, takes place normally once a year, usually after the arduous duties of rearing the young are over ; but there are numerous exceptions to this, some birds acquiring two, three, or exceptionally even four, more or less com- plete annual changes of plumage, and further, these moult periods " must not be confounded with occasional new growth at any time and anywhere to replace feathers accidentally torn out." In order that the ordinary activities may not be seriously interfered with during the period of moult, there is a distinct relation between the feather loss and feather gain, most birds at no time being deprived of either the power of flight or the protection afforded the body by the feathers, and furthermore this fall and replacement is more or less synchronous from the Opposite sides of the body. Thus in probably all of the great group of Passerine birds, the moult of the flight feathers begins in the middle of the wings with the practically simultaneous fall of the proximal or innermost primary on each side. As soon as the old feather has fallen, the new-forming feather pushes into view, and grows rapidly, and by the time the expanded portion of the feather itself is . breaking from the apex of the follicle the next primary falls, and so the renewal by pairs proceeds outwards. With the secondaries the renewal proceeds in the opposite direction, that is the outer or distal one on each side falls first, this loss being very nearly coincident with the fall of the fifth or sixth primary, and their replacement by pairs proceeds towards the body. In some cases, as in Ducks, Geese, Swans, and Flamingos, the wing-quills are all shed at once, thus rendering the birds practically helpless for a short time, but this is very exceptional. The feathers of the tail are also normally renewed in pairs, the central pair falling first, followed by the quills next adjacent on either side. The process, however, is much more rapid than in the wings, for by the time the outer pair has fallen the middle ones are often not half grown. The renewal of the body feathering is in less obvious sequence, though " the moult regularly begins at fairly definite points in the feather tracts, radiating from them in such manner that the outer rows of feathers where the tracts are widest, and their extremities are normally the last to be replaced." — DWIGHT. Renewal of Parts other than Feathers. — Although the renewal of the plu- mage is the most important event of this kind, the feathers are by no means the only part of the integument that is periodically changed. Thus in certain Grouse the claws or pectinations along the sides of the toes become greatly lengthened in winter and are partially shed or worn down in spring and summer ; the Puffins and Auklets shed portions at the base of the bill and around the angle of the mouth; the Penguins, or at least the King Penguin, moults the bright orange- colored membrane at the base of the bill; the American White Pelican develops a curious appendage on the upper mandible which is shed at the close of the nest- ing period. These phenomena and others of similar character will be more fully described under various forms exhibiting them. i o Introduction Age of a Feather. — After a feather attains its maturity the contents of the quill dry up and it is incapable of further development. It becomes, so to speak, "dead." A great deal has been written to prove the contrary; namely, that a feather may, after it reaches its maturity and does duty for a varying length of time, again take on a period of active growth and change. This is to account for certain so-called "changes of plumage without moult." But it seems to be now settled beyond any reasonable doubt that when a feather completes its growth, and the contents of the quill become dry and "lifeless," it can never reinaugurate the process. There may be a fading or bleaching, or the outer extremities of the feather may be abraded in one manner or another, resulting oftentimes in a freshening or brightening of the plumage, as for example in the spring plumage of Purple Finches, Crossbills, etc., but this is quite different from a renewed growth and repigmentation of the individual feathers. This brightening of the plumage in the above-mentioned species was long ago shown to result from the fact that the winter feathers have red barbs and gray barbules, and on the latter wearing away, the red elements of the feather are exposed. Beyond these rela- tively slight changes by abrasion or disintegration of the tips, or by fading, change of plumage can only result from moult. It is only within the last few years that any extended researches have been undertaken in this country with a view of elucidating the sequence of plumages and moults in our birds, and while an extensive body of facts has been accumu- lated, much still remains unknown. Those who wish to look further into this subject should consult the papers mentioned below by Witmer Stone 1 and Dr. Jonathan Dwight, Jr.2 The latter author has placed the terminology of the subject on a uniform and logical basis. His scheme will be understood from the following tabular arrangement : — PLUMAGES MOULTS 1. Natal (Down). i. Postnatal. 2. Juvenal ('First plumage'). 2. Postjuvenal. 3. First winter. 3. First prenuptial. 4. First nuptial. 4. First postnuptial. 5. Second or adult winter. 5. Second or adult prenuptial. 6. Second or adult nuptial. 6. Second or adult postnuptial. Nests and Eggs of Birds. — A word should perhaps be said in regard to the nests and eggs of birds, but in the space at command it can be but the briefest outline of a broad and extremely complicated field. It is perhaps unnecessary to state that all existing birds, without a known exception, lay eggs. To a casual observer, viewing a large collection of birds' eggs, the variation in size, shape, color, markings, etc., seems almost infinite. For the differences in size he is 1 " The Moulting of Birds with Special Reference to the Plumages of the Smaller Land Birds of Eastern North America," Proc. Acad. Nat. Sci. Phila., 1896, pp. 105-165. 2 "The Sequence of Plumages and Moults of the Passerine Birds of New York," Ann. N. Y. Acad. Sci., vol. 13, 1900, pp. 73-360, plates 1-7. Nests and Eggs of Birds 1 1 prepared from his knowledge of the known differences in the sizes of birds pro- ducing them, yet there are noticeable surprises even in this respect. But the attempt to account for the striking differences in shape, color, and markings of eggs seems an almost hopeless one, yet such attempts have been made, though, it must be confessed, with varying degrees of success. Theoretically we may be justified in presuming that the lowest of existing birds, that is those that are supposed to approach most closely to their reptilian ancestors, should produce eggs or have habits of nidification showing the closest approach to the reptiles. An examination of the facts, however, shows that this relationship is capable of demonstration to a limited degree only. In the first place, it appears that much is still to be learned regarding the oology of existing reptiles. Broadly speaking, the eggs of all reptiles are white in color and spherical or ellipsoidal in shape. Nothing is at present known regarding the eggs of either the ancient reptilian or avian ancestors of our birds, although, as Shufeldt has suggested, it is by no means impossible that such remains may sometime be found, especially those of the Toothed Birds. Fossil eggs of turtles have been obtained, as well as fossil or subfossil eggs of a few species of birds, but they throw little or no light on the question at issue. It is, then, from this hypothetical starting-point that all the marvelous diversity observable in the eggs of living birds has been developed, but the steps by which it has been accomplished are, and must perhaps remain, obscure. Natural selection has doubtless played a most important role, though the "whys and wherefores" are far from being satisfactorily answered. There are certain salient groups of facts that stand out boldly, yet the exceptions are so numerous and marked as to prevent establishing any adequate chain of cause and effect. Thus practically all birds that nest in holes, such as the Woodpeckers, Kingfishers, Bee-eaters, Rollers, Hornbills, Barbets, Puff-birds, Trogons, Toucans, Parrots, Parakeets, and Swifts, lay white eggs, yet the coordinate groups of Owls, Hummingbirds, and Pigeons, that build an open nest, also lay white eggs, while many birds that habitually nest in holes lay spotted or even richly colored eggs. Again, it is often possible to trace a marked similarity in pattern of coloration throughout nearly all the species of a whole natural family, or a large genus, but for which "the conditions of environment offer no explana- tion, since it as often occurs in cosmopolitan groups as in those of local distribu- tion, and which, in the present state of our knowledge, seems wholly inexplicable." Theory of Birds' Nests. — So, also, are we without an adequate theory of birds' nests. "Why the thousands of species of birds," says Dr. J. A. Allen, "build each a peculiar nest, differing more or less in situation and architecture from those of all other species, is a question which has yet received no satisfactory answer. As a rule the nest, including its location, the materials and manner of its constructure, is as distinctive of the species as the number, size, form, and color of the eggs, or, in some instances, as any fact in its history, not excepting even the details of structure and coloration of the bird itself. Why this is so we can perhaps explain when we can satisfactorily account for the diversity of song that is scarcely less a scientific characteristic." The attempt has been made to explain it on the ground of a connection bet ween 1 2 Introduction the colors of the female and the mode of nidification. That is, according to Wallace, "when both sexes are of strikingly gay and conspicuous colors, the nest is such as to conceal the sitting bird, while, whenever there is a striking contrast of colors, the male being gay and conspicuous and the female dull and obscure, the nest is open and 'the sitting bird exposed to view." This condition un- doubtedly prevails in many cases, but the exceptions are so numerous and so important, that the "theory" fails of adequacy. CHAPTER II THE ANATOMY OF BIRDS BY FREDERIC A. LUCAS HERE are, broadly speaking, two sets of characters to be found in the skeleton of any animal. There are, first, those which bear a direct relation to its position in the class of vertebrates, bear witness to its origin and relationship, and are shared to a greater or less extent by every member of the group to which it belongs. These are termed structural or morphological characters. There is also another set of characters which are connected with the animal's habits or mode of living and are believed to have been acquired during the de- velopment of the species, and are called secondary or teleological. It is owing to FIG. 6. — Wing bones of a Bat. FIG. 7. — Wing bones of a pterodactyl. the fact that the skeleton is influenced by these two great factors that it is possible to tell from the skeleton, or even from parts of it, not only what position the animal holds in the scale of life, but what were its habits as well. So the modifications of a bird's skeleton are primarily morphological, those due to the fact that it is a bird, but these are associated with others rendered necessary by the adaptation 13 14 The Anatomy of Birds of the fore limb for flight and its consequent withdrawal from use in any other form of locomotion, or for taking food. And in birds these last so overlay the others that the classification of birds is a very difficult matter. This is well shown by the long use of the divisions Ratitae and Carinatae, which depended mainly on the presence or absence of a keel to the sternum, when this and a number of other characters depended upon whether a bird did or did not fly. So the structure of a bird's skeleton depends first upon the fact that it is a bird, secondarily upon the manner in which it moves about, and thirdly, to a still less degree, upon the way it gets its living. Flight in itself is not a distinctive charac- ter, for mammals fly to-day, and reptiles, in the shape of pterodactyls, flew ages ago, having successfully mastered the problem of flight about the time the bird had taken its first lessons in the art. But the manner in which the fore limb is modified, the ground plan, so to speak, on which it is built, is a primary morphological character and differs in the birds, mammals, and reptiles. In the Bat (Fig. 6) the four fin- gers of the hand are greatly length- ened for the support of the membrane forming the wing ; in the flying reptile (Fig. 7) the membrane is supported wholly by the enormously developed fifth or little finger. In the bird the bones of the hand are lessened in number and peculiarly modified for the attachment of feathers which form the highest type of wing. The general characteristics of a bird's skeleton are lightness, length of neck, very decided difference between the fore and hind limbs, and reduction in the apparent number of bones of the hand and foot (metacarpals and metatarsals) by their fusion with one another. The skull joins the neck by a single condyle as in reptiles, and, also as in reptiles, the ankle joint is between the bones of the ankle and not between the leg and ankle as in mammals. The jaw is not attached to the cranium directly as in mammals, but by a free quadrate as in snakes and some extinct reptiles. In existing reptiles other than snakes the quadrate is fixed. Many ribs of the chest cavity bear little processes directed upwards and backwards, termed uncinate processes, and these are found in all birds save the Screamers, although almost wanting in the Secretary bird. Outside the class of birds such processes occur only in that curious New Zealand reptile, the Hatteria, and, in cartilage only, in Crocodiles. So, in many important particulars the skeleton of a bird resembles that of a reptile, and this led Huxley to unite the two in a common superclass, Sauropsida. This possession of characters in common with reptiles is why it is con- sidered that if birds have not been directly derived from reptiles, they have had a common origin. From the strong resemblances between birds and dinosaurs it was long thought that these reptiles were the parent stock of birds, but this theory has been practically abandoned. FIG. 8. — • Wing bones of a Pigeon. The Anatomy of Birds in FIG. 9. — Wing bones of a young Ostrich. Parker'.) (After I, II, III, digits; i, 2, 3, metacarpals; a, b, c, carpal bones. Professor Seeley has thought that the resemblances between birds and ptero- dactyls was more than superficial, but he stands practically alone in this view, the most commonly accepted working theory being that birds and dinosaurs have had a common ancestry. The extent to which the skeleton of a bird is permeated by air usually bears a direct and apparent ratio to its mode of life. Thus the Condor and other soar- ing birds, such as the Frigate-birds, Cranes, and Screamers, have very lightly built skeletons, and Ducks and other water fowls have the cavities of the long bones filled with marrow, while the bones of the strictly aquatic Pen- guins are filled with bony tissue. That the lightness of the skeleton does not necessarily appear in con- nection with the power of flight is shown by the Hornbills and especially by the larger species, for in these birds of heavy, lumbering flight, the air penetrates to the very tips of the toes. On the other hand, in birds like the Condor and Frigate-bird this pneumaticity, or presence of air in the bones, is believed to aid in oxygenizing the blood and in adjusting the air pressure when a bird descends rapidly from a great height. It may also be connected with lessening the sudden shock that takes place when a Gannet or Brown Pelican plunges headlong into the sea. It is usual to commence the description of a skeleton with the skull, but while the skull is of the utmost importance to the systematist, it is a complicated structure whose topography is by no means easy to understand, and whose numerous parts bear equally numerous and unfamiliar technical names. So we may slight this, leaving it to be briefly described later on, and begin with the wings, which, next to the feathers, are the most obvious features of a bird. The wings of a bird comprise the same parts as the fore limb of a mammal or reptile, and save in the hand, we can readily recognize these various parts, the upper arm (humcrus), forearm (radius and ulna), wrist, and hand. The bones of the fore limb are modified for the support of the large feathers forming the wing, the hand being reduced to three fingers, while only two of these, those to which the primaries are fastened, are of much use. FIG. 10. — Wing bones of a young Chicken. (From Coues's " Key.") A, shoulder; B, elbow; C, wrist or carpus; D, tip of third finger; a, humerus; b, ulna; c, radius; d, scapholunar bone; e, cuneiform bone; /, g, epiphyses of metacarpal bones /, k, respectively; h, meta- carpal and its digit i. i6 The Anatomy of Birds The wrist of the adult bird, frequently called shoulder, consists of but two bones; the part corresponding to the palm of the hand comprises three meta- carpals and two carpals solidly fused into one mass, though this can be seen only in a very young bird. Following this is a short finger on the front edge of the wing bearing the so-called bastard wing, one long central bone and one shorter more or less pointed. The stages by which the clawed hand has been trans- formed to a wing may be gathered partly from fossils and partly from a study of the embryo, but it is not quite certain whether the first finger of a bird, that bear- ing the so-called spurious wing, corresponds to the first or second finger of man, with the probability in favor of its being the second. The wing bones are lengthened or shortened in a pretty direct ratio to the rapidity with which the wings are moved, being longest in such sailing birds as the Albatross and shortest in the Pigeons and Hummingbirds. The short- ening is greatest in the humerus; for while in the Albatross and Frigate-bird the upper arm and forearm are about equal, in the Pigeons the humerus is somewhat shorter, and in the Hummingbird very much shorter, than the succeeding bones. This relates to the fact that a FIG. ii. — Wing bones of an embryo Hoactzin. K. Parker.) (After W. Wing bones of an embryo Hoactzin, when the embryo was about half ripe for hatching, showing the claw on the first digit, dg1; on the second KirH'c wina ic digit, dg'; the rudimentary claw on the third digit, a, of a fourth digit, dg*; h, humerus; r, radius; u, ulna; re, radiale; ue, ulnare; i, intermedium; c, centrale; dcl, dca, distal carpals. < v shoulder joint representing the fulcrum, the muscle the power, the end of the wing the weight. The shorter the wing, the easier it is to move it rapidly; the more rapidly it is moved, the stronger must it be. The wing of a Condor or Albatross would break, were sufficient power applied to move it as fast as that of the Pigeon. The rapidity of the wing stroke is also indicated by the development of the processes about the inner end of the humerus for the attachment of wing muscles, these reaching by far their greatest development in Hummingbirds. The wing is supported by the coracoid, a bone abutting on the front of the breast-bone and raking forwards and upwards. This bone, represented in the higher mammals by a mere process on the shoulder, forms half of the shoulder joint in reptiles and also in the Echidna and Platypus, and by far the greater part of the shoulder joint in birds, that part of the shoulder blade being much reduced. In perching birds the coracoid is long and slender, and in birds which soar or sail it is shortened and broadened, for it is a rather curious fact that while the amount of muscular power employed in flight is much smaller in sailing birds than in others, the support for the wing is much more strongly built. In the The Anatomy of Birds ij Frigate-bird, which is perhaps the most expert bird of flight, the area of wing muscle is proportionately smaller than in any other bird, while the wishbone is united at its apex with the breast-bone and soldered to the coracoids at the other end, thus forming a rigid support for the wing. The shoulder blade is slender and as a rule more or less pointed, the Penguins being exceptional in having a broadly I expanded scapula, while the Woodpeckers are characterized by having the end bent downwards. Attached to the coracoids in front is the wishbone, which represents the clavicles or collar bones of other animals. This is usually "U"- or " V "-shaped, with the apex near the keel of the sternum or even united with it, as in the Stcganopodes. In some Parrots and Toucans the upper portions only of the clavicles remain attached to the coracoids, and in the struthious birds, save Emeu, clavicles are entirely lacking. In birds of prey the clavicles are broadly "U "-shaped and heavily built, serving to brace the wings apart, but in the majority of birds they are of little structural importance, and in such ad- mirable flyers as the Hummers are practically of no use. The breast-bone (Fig. 12), sternum, bears a direct relation to habits, and to a less extent is valuable in classification. While the terms Ratitae and Carinatae, keelless and keeled, are convenient in forming a key, and the corresponding condi- tions were formerly held of primary importance in classifying birds, they have been abandoned by the best anatomists, as they do not express the truth. The development of the keel of the sternum bears a direct relation to the extent to which a bird moves its wings, whether in flight or swimming. Birds which do not fly have the keel of the sternum small or absent, according as the power of flight has been lost, geologi- cally speaking, for a longer or shorter period of time. The members of the Auk family fly somewhat heavily, owing to the small size of their wings, but as these are used for flying under water as well as above it, the breast muscles and sternum are large. For the same reason the Penguins, which do not fly at all, have a large sternum, since they swim entirely with their wings, presenting in this respect an analogy to the eared seals, which swim with their fore limbs. The keel of the sternum is very much reduced and the body of the sternum greatly shortened in birds which sail, this mode of flight involving the expenditure of comparatively little muscular energy. The Albatross has a small breast-bone, and the Frigate-bird smaller still, and these birds are those which fly with the fewest movements of the wing. On the other hand, birds that fly by strokes of the wings have large breast muscles and a correspondingly large sternum, these reaching their maximum in the Hummingbirds, whose skeleton when brought up to the size of a Pigeon is seen to be very powerfully built. The Pigeon, by the way, exhibits the development of the sternal keel for powerful flight. The front part of the sternum bears the coracoids ; the ribs are attached to its sides, while the body of it supports the viscera. In all water birds the breast-bone, FIG. 1 2. — Sternum of a Guinea Hen, seen from in front. (After Gegenbaur.) crs, crest; c, coracoid bone. i8 The Anatomy of Birds is long, corresponding to the long bodies of these birds. The hinder portion of the breast-bone may be entire, perforated, or notched, the notches being two or four in number, reaching their extreme in the fowls in which the body of the ster- num is very small and the lateral processes extremely long and slender. The front of the breast-bone (Fig. 13) may bear a projecting process, or "manubrium," and this may be developed from the inner face of the bone, spina internet, or outer, spina externa, at the region of the keel. The manubrium may be a spine (Curassows), or low projection (some Owls), while the extreme develop- ment is found in the long "Y "-shaped pro- cess so characteristic of the Passeres, the ^•feHT^ /t.f. Woodpeckers coming next in this respect. These characters are apparently not asso- ciated with any corresponding modifications ^ >a^" p'°'p" FIG. 13. — Sternum of Sage Grouse, show- ing component bones. (After Shufeldt.) FIG. 14. — Skull of Rhea, dorsal view. (After Pycraft.) /./, temporal fossa; p.o.p., postorbital process; m.e, mesethmoid; l.p, lachrymonasal pillar; /, lachrymal; mxp.p, maxillopalatine; n, nasal. in the habits of birds, and are, therefore, of great importance in determining the affinities of various groups. % On either side of the breast-bone are little prominences to which the ribs articulate, and in many birds these articulations are found well forward and on a triangular-shaped process, termed the costal process. The uppermost bone of the leg, the femur, is always short, even in wading birds, and usually pneumatic, or permeated by air. The extreme of shortness and width is found in the extinct diving bird Hesperornis, in which the femur suggests that of a seal. The knee-pan, or patella, is usually small, except in such swimming birds as Cormorants and the extinct Hesperornis, where the head of the tibia is short, and it is largely developed to serve for the attachment of muscles. In Grebes and Loons the upper end of the tibia is greatly extended and the knee-pan corre- spondingly reduced, appearing as a small splint of bone back of the process. The Anatomy of Birds 10 The tibia is much the larger bone of the lower leg, the fibula being flat and splint- like in character, never quite reaching the lower end of the tibia and commonly not extending more than two thirds of its length. The length of the tibia is related to a bird's habits, being longest in wading birds, coming next in runners, and of considerable development in swimming birds. The foot of a bird never contains dpx more than four toes, and there may be but two, as in the Ostrich, while the three principal metatarsal bones are united into one, with which the second row of tarsal bones is fused, this form- ing the tarsometatarsus, or, as it is atb p.pm par Fie ant.b.f 15. — Skull of Rhea, ventral view. Pycraft.) (After p.pmx, palatine process; par, parasphenoidal rostrum; v, vomer; pa, palatine; pt, pterygoid; bt.p, basipterygoid; p.p, paraoccipital; ant.b.f, anterior basioccipital fonta- nelle; mxp, premaxillary-palatine process. FIG. 1 6. — Skull of Ptilotis. (After Parker.) p.px, palatal process of premaxillary; pr.pa, pre- palatine; mx.p, maxillopalatine plate of maxillary; r, vomer; eg, pterygoid; d.px, dentary process of pre- maxillary; mx, maxillary; ip.a, interpalatine ridge; p.as, parasphenoid ; epg, epipterygoid hook. commonly called, tarsus. The bones corresponding to our heel bone, calca- neum, and its neighbor, astragalus, unite with the tibia, so that the ankle joint of a bird, like that of reptiles, is between the bones of the ankle, and not as in mammals between the leg and ankle. The upper end of the tarsus and its relation to the tendons is a fair index to the position of its owner, being simplest in Ostriches and other birds undeniably low or generalized in character, and more complicated in higher forms, reaching 20 The Anatomy of Birds its greatest complexity in the perchers, in which the hypotarsus, as it is termed, is pierced for the passage of four or five tendons. In the Crow, for example, there are four large and one small perforation, in the Clamatores but foun, and one of these is closed by cartilage and not by bone; in the Picariae there are but one or two tendinal perforations, and in the divers but one, so that the specialization of the tendons and that of the tarsus go together. The three divisions of the lower end of the tarsus indicate that it is composed of three bones, but these bones are clearly shown only in embryos, in young Ostriches and in Penguins, where the bones, though united, are plainly indicated throughout life, this retaining of a primitive condition being one of the characters which has led many good authorities to place the Penguins in a group contrasting with all other fan-tailed birds.1 The leg attaches to the hip-bone, or pelvis, each half of which is composed of the usual three bones, ilium, ischium, and pubis, although these fuse together at an early date and show as separate bones only in very young birds. In all birds the pubis is directed backwards, and the greater part of the ilium lies in front of the hip-joint, this being a point where existing birds differ from existing reptiles. In the lower birds, as the Ostriches and Tinamous, the two principal bones of the pelvis, the ilium and ischium, are free from one another behind, this being a primitive character in which these birds resemble reptiles. The Cassowaries are an excep- tion in having these bones united. In the vast majority of living birds (the Neognathse) the ilium and ischium are firmly united. The pubic bones, the long, slender, lowermost bones of the pelvis, unite posteriorly in the Ostrich, but are free in other birds and are frequently widely separated ; they may even be nearly lacking, as in Eagles, in which the hinder por- tions only remain. The outward flare and generally open character of the pelvis below has to do with the question of room for the passage of the large and brittle egg. Birds that fly much, and especially sailing and soaring birds like the Petrels and Frigate-birds, have a broad, short pelvis, while in water birds it is long and narrow, much the same condition being found in flightless birds which run much. The neck vertebrae of birds are peculiar from the character of their articula- tions, which are saddle-shaped, concave one way and convex the other, a form termed heterocoelous, and one that allows great freedom of movement in both planes. Theoretically the ball-and-socket joint permits the greatest amount of motion, but in practice this form of joint is usually combined with some arrangement which checks its movements. Thus in the snake, while there is the utmost freedom of movement from side to side, there is but little play verti- cally. The neck of the bird is always long and the vertebrae numerous; this is 1 Recently described fossils indicate that in the earlier Penguins, the metatarsals were not separated to the extent they are in existing species. FlG. 17. — Right tar- sus of Penguin, Apteno- dytes pennanti. The Anatomy of Birds 21 necessary in order that the bird may reach all parts of its body with the tip of its bill, and secondly, that it may obtain food. Thus long legs and long necks go together, or, as in the Sandpipers and Snipe, there is an increase in the length of the bill, while Swifts, Swallows, and Goatsuckers, which capture their prey in mid-air, have short necks. Swans, which do not dive, have much longer necks than diving birds, or Geese, which feed largely on land, The very long neck of the Darter is associated with its habit of suddenly straightening the neck and impaling fish on its sharp bill. Usually the last two neck vertebrae bear free ribs, these being but the lengthen- ing and freeing of the long processes running backwards from the sides of the front of the vertebrae. That these are really ribs may be readily seen in a young Ostrich, in which they are free, but while later on they become united with the bodies of the vertebrae, the last two remain free, although they do not reach the sternum. The thoracic region of a bird, the body proper, usually consists of a com- paratively small number of vertebrae bearing long ribs, the foremost of which are attached to the sides of the breast-bone. Water fowl, like the Loons, Auks, and to a lesser degree Ducks, have the longest bodies, soaring birds the shortest. Several of the vertebrae in the center of the series are fused or ankylosed together to stiffen the body for flight, a free vertebra or two next the pelvis permitting some motion here. The sacral vertebrae, or those to which the pelvis is attached, are really but two, as in reptiles, or in rare cases three in number, but in front and behind are added vertebrae from the back and tail region, the result being a long series of vertebrae firmly united in one mass and furnishing ample attachment for the pelvis and a firm support for the legs. The number of bones in this synsacrum, as it is called, can only be clearly seen in young birds, but there may be from twelve to as many as twenty. Finally comes the caudal series of free tail vertebrae, which may vary from five to as many as ten, the average number being about six, and in all the higher birds, or Neognathae, terminating in the flattened urostyle, to which the tail feathers are attached. This bone in turn comprises four to six modified sections. The skull of a bird, roughly speaking, is divided into two parts, the beak and brain case. The beak portion, which is very directly concerned in the getting of food, is subject to many and great modifications ; the rear portion, being away from direct modifying influences, is less altered, and here the palatal part of the skull is of the most importance for purposes of classification, for the less a part is subject to outside influences and the less a creature's habits have to do with any part of the body, the less, theoretically at least, should that part be subject to modification, and the more important it is for use in classification. There are two existing types of skull structure by which birds are divided into two great groups, the Palaeognathae or Dromaeognathae, including the Ostriches and their allies, and the Neognathae, Euornithes, or Eurhipidurae, which comprise the vast majority of birds. These types are sharply marked, indicating that at the very outset of their career, birds split into these groups, if indeed they may not FIG. 18. — Anatomical plate. (After Shufeldt.) i, skeleton of typical passerine bird, the White-rumped Shrike (Lanius ludovicianus excubitorides); 2, pelvis of young Sage Grouse (Centrocercus urophasianus); x, ilium; y, ischium; 2, pubis; 3, anterior view of right femur of Sage Grouse; 4, anterior view of right tibia and fibula of adult Sage Grouse; 5, tarsometatarsus of adult Sage Grouse; 6, thoracic and pelvic bones with scapular arch of White-tailed Ptarmigan (Lagopus leucurus) ; 7, foot of young Sage Grouse showing free centrale and indications of the three component tarsals. 22 The Anatomy of Birds 23 have originated from two distinct types of reptiles. Unfortunately, as previously noted, these modifications can be described only in technical language and can probably be best understood from a study of the accompanying figures. In the dromaeognathous type of skull (Figs. 14, 15), so called because it is typically found in Ostriches, the vomer is broad and unites in front with the maxillopalatines, while behind it receives the posterior extremities of the pala- tines and the anterior ends of the pterygoids, which are thus shut out from joining the sphenoid; the sphenoid bears on its sides long basipterygoid pro- cesses which give it something of a cruciform shape. In birds with this type of skull the quadrate, the bone to which the lower jaw is joined, is rather short and clumsy and its articular head is single or but faintly divided into two portions; the quadrate is also locked into place by the surrounding bones. In all these particulars the dromaeognathine skull more nearly resembles that of a reptile than does that of the majority of birds, a point that may be best appreciated by comparing the figures. In the euornithic type of skull (Fig. 16) the palatines articulate with the pterygoids and both touch the sphenoid at their point of junction, and the back of the vomer embraces the sphenoid between and above the ends of the palatines. The quadrate has two heads and is loosely joined to the cranium. This arrange- ment prevails in the majority of birds, and is termed the euornithic type of skull because it is characteristic of the Euornithes; it is also called neognathic because it is believed to be more recent or newer than the Ostrich style and further removed from the reptilian skull. Basipterygoid processes may be present, but usually in the form of low facets which articulate with projections on the pterygoids and often serve as braces to the beak when this is slightly movable, as in Ducks and Parrots. The neognathous style of skull is subject ~to several important modifications which characterize great natural groups of birds. These are the schizognathous, desmognathous, and aegithognathous types,1 which may be briefly characterized as follows : When the vomer is pointed in front and entirely free from the maxillo- palatines, and these are free from each other, the skull is termed schizognathous; when the maxillopalatines are expanded and fused with each other, the vomer being small or absent, the skull is desmognathous; when the vomer is expanded in front and free from the maxillopalatines, and these are slender at their point of origin and disjoined, the skull is said to be segithognathous. The second of these types, the desmognathous, is to some extent a modification of the first, brought about by the development of bone in the palatal region which binds the various parts together and hides its real structure. Thus desmognath- ism occurs in varying degrees in birds obviously closely related, while the trans- formation of one type of skull into another is admirably illustrated by the Cor- morant. This bird has at first a schizognathous skull, but by the time it takes 1 Parker applied the term saurognathous to the skulls of Woodpeckers, but in the opinion of the writer and others, the modifications found in the skulls of these birds are largely, if not entirely, mechanical and depend on the use of the skull as a pick. To a lesser extent and for similar reasons some of the features are present in the skull of the Nuthatch. 24 The Anatomy of Birds to the water, growth of bone in the palatal region has converted it into a com- pletely desmognathous cranium. Two other features remain to be considered in connection with the skull, the hyoid, and those modifications of the nasal bones and narial openings termed by Garrod holorhinal and schizorhinal. In the holorhinal type the openings are FIG. 19. — Tongue and hyoid bones of various birds. (After Lucas.) a, hyoid of Pewee (Sayornis fuscus) ; b, hyoid of Cormorant (Phalacrocorax wile); c, hyoid of Muscovy Duck (Cairina moscliala); d, hyoid of Hummingbird (Selasphorus rufus) ; e, hyoid of Flicker (Colaptes auralus). All figures drawn to the same absolute scale, ch, ceratohyal; bh, basihyal; bb, basibranchial ; cb, ceratobranchial. more or less oval, the posterior border curved and lying in advance of the posterior ends of the premaxillaries. In the schizorhinal type the openings are more or less elongate, with the posterior border angular or slit-like and lying back of the posterior ends of the premaxillaries. These features are, to some extent, valuable in classification, but by no means of the importance at first ascribed to them by Garrod, being one of the many emphatic warnings that birds may not be classified by any one set of characters, but by the resultant of many. The Anatomy of Birds 25 The beak part of the skull, as just stated, is subject to great modifications connected with the taking or manipulation of food, and may be long and slender like a probe, broad and flat, or short and strongly made for crushing seeds. The extent to which habit and modification may go is shown in the Pelican, Gannet, and Cormorant, and in all these diving birds the nostrils are completely filled up and the roof of the mouth strengthened by the growth of the bone. The Cormorant starts in life with open nostrils, but by the time it is ready to take to the water and seek food for itself, the nostrils are completely closed by the growth of bone and overlying horny beak. These changes are accompanied by others in the bones of the palate by which the structures of this region are entirely changed and its real characters obscured. The hyoid, all but the front portion, corresponds with the first gill arch of a fish and supports and controls the motion of the tongue. The tongue itself is built upon the front portion of the hyoid, which is subject to little modification, but the extent to which the tongue can be protruded depends on the length of the bones of the hinder part. Hence in the Woodpeckers, which use their tongues as probes, the hinder parts of the hyoid curl up around the back of the head and may even, as in Colaples, pass over and into the nasal chamber nearly to the tip of the beak. Thus from bill to toes, not merely the external form of the bird, but the underlying skeleton as well, is fashioned to adapt the bird to its surround- ings. As William Kitchen Parker used to say, "Adaptation, adaptation is the keynote to the structure of a bird." CHAPTER III THE GEOGRAPHICAL DISTRIBUTION OF BIRDS HE distribution of life over the globe is known as biogeography. With that branch of the subject dealing with the distribution of animals (zoogeography) we are of course at present only concerned with the distribution of birds. Although earlier attempts had been made to correlate certain observed facts of avian distribution, it was not until about the middle of the last century that the subject was placed on a logical and scien- tific basis. These earlier attempts failed because it was undertaken to delimit life areas by degrees of latitude and longitude, or by the lines of political division, while in the light of present understanding it needs but a moment's reflection to disclose the fact that the distribution of life on the earth must depend upon natural causes and conditions, and only occasionally and quite by accident to coincide with the political divisions. Inasmuch as most birds possess the power of flight, which enables them to pass easily and quickly from one area to another, or, within certain limitations, even from one hemisphere to another, it might be inferred that their distribution would be relatively uniform, but such is far from being the case. If a person reasonably familiar with the bird life of eastern North America should journey around the world, first crossing this continent, and thence by way of Central America through South America, and by way of Polynesia to New Zealand, Australia, Asia, Europe, and Africa, he could not fail to be impressed with the marked differences in the birds coming under notice. In a few Ceases, such as afforded by the pelagic and far- wandering Albatrosses, Petrels, Gulls, Terns, and Tropic-birds, he might find the same species at several widely separated points in the journey; in many instances he would note the presence of familiar groups, — as Ducks, Woodpeckers, Kingfishers, Hawks, Owls, — but in the vast majority of cases the species would be entirely different, while in not a few, whole families and orders would appear and disappear in succession. It is not always easy to account for the presence or absence of certain genera or other groups of birds in this or that part of the world, especially when it appears that the conditions of environment in localities whence they are absent are apparently similar to those obtaining where they are present, and were it not for the aid rendered by geology and paleontology we should often be left without an adequate explanation. It is no doubt true that certain groups of birds now 26 Causes Affecting Distribution 27 confined to circumscribed areas could exist as well in other parts of the world where climatic and food conditions are practically similar, provided the avenues for reaching them were open. For instance, the abundant fresh-water bodies of the New World, teeming with fishes and other aquatic life, seem admirably adapted to support a varied Kingfisher fauna, and doubtless our Troupials (Icterida) could change places with the Old World Starlings (Sturnidce'), or our Wood- warblers (Mniotiltida) with the Old World Warblers (SylviidcR). These groups, and of course many others could be mentioned, appear to have reached their present standing in approximately the same geographical areas they now occupy, and long since all land connection between their respective habitats has been cut off. In the light of geological evidence it is beyond dispute that in the past numer- ous large land masses have been many times joined together and many times rent asunder. In this way continents as well as lesser land areas have been suc- cessively joined and cut off from one another, and each junction has left the way open for an exchange of life forms. North and South America have been many times severed and united; Australia by a relatively slight subsidence has lost New Zealand, and Madagascar was undoubtedly at one time a part of the conti- nent of Africa. Both New Zealand and Madagascar were stocked with certain animal forms while they retained connection with their parent masses which the sea barrier has since prevented from commingling, at least to any great extent. The important bearing of these facts on distribution is obvious. Another and very important geological event was the glacial epoch. This vast ice-mass, sweeping down for hundreds of miles from the pole, profoundly modified the life, not only in the area actually covered by the ice, but far beyond its actual border. Many forms must have been crushed out of existence, while others, enjoying perhaps better means of migration, were pushed before it towards the tropics, which resulted in intensifying the struggle for existence in an area probably already well stocked. The forms of life from both sources that could not readily adapt themselves to the changed conditions were pushed to the wall and left little or no trace of their existence. By the recession of the ice, territory was gradually reclaimed, which was occupied by the surviving forms, with the ex- ception of those typically northern forms remaining permanently stranded in southern mountain areas. To paleontology we are also indebted for some contributory data regarding distribution, for while the fossil remains of birds are not very numerous, they are often sufficiently so to show that many groups once enjoyed a much wider dis- tribution than now. Paleontology thus makes plainer the possible lines of travel by which the descendants of the ancient forms have reached their present loca- tions. But this class of facts is far less important than those last considered, for the paleontological record is less complete for birds than for almost any other group. It is mainly of value in fixing the antiquity and affinities of certain groups, and even here it is often distressingly meager. Of the causes controlling or influencing distribution it is generally admitted that temperature and humidity are the chief factors, and, according to Merriam, 28 The Geographical Distribution of Birds "it has been found in the case of mammals and birds that the effects of tempera- ture, estimated numerically, are more than three times greater than the effects of humidity upon genera, and many times greater upon the higher groups." While there is some1 difference of opinion as to the exact period during which temperature exerts the greatest influence, "there can be but little doubt that for both animals and plants it is the season of reproductive activity." There are various other factors, aside from those already mentioned, that are known to exert a greater or less influence on geographical distribution. The character of the soil, which carries with it an effect on the plant and insect life, may be mentioned, as well as the mechanical purity of the atmosphere as evidenced by the prevalence of fogs, etc. Deforestation, the usual mark of the advent of civilization, has quite markedly affected distribution, and the extension of culti- vated areas by means of irrigation over lands previously arid has increased the habitable areas for some species, and has also resulted in displacing many indige- nous forms. Mountain ranges have often been considered to be efficient barriers against distribution, and that they have an effect is true, but it is mainly the effect of altitude and temperature ; for if conditions are similar on opposite sides of a range, they will usually be found inhabited by the same forms, which may have reached these positions by passing around the extremities of the mountains or by means of passes through them. The real barrier is climate and not mass. Thus both sides of the Rocky Mountains as well as the high Sierra in California, are found to be inhabited by the same species of birds, and, says Merriam: "The great Himalaya has little or no influence in bringing about the really enormous differences that exist between the faunas and floras of the plains on its two sides, for these dissimilarities are due primarily to the great difference of temperature resulting from unequal base level, the Thibetan plateau on the north being several thousand feet higher than the plain on the south." Oceanic bodies of water have of course a powerful effect on distribution, especially of land birds, but even here certain limitations must be borne in mind. To purely terrestrial animals the presence of even a moderate width of open water may prove an efficient barrier, but to birds, endowed as they are with the power of flight, it is less so than might be supposed. The Galapagos Islands lying six hundred miles off the coast of Peru have been stocked with an abundant fauna of land birds, evidently of South American and West Indian crigin, and the Azores, seven hundred miles distant from South Europe, have a fauna of one hundred and twenty species and subspecies of birds, all Old World forms, the ranks of which are being yearly augmented by fresh arrivals. Within the last fifty years the White-eye (Zosterops ccemlescens}, a small passerine bird about the size of our Parula Warbler, has crossed over the twelve hundred miles of open water sepa- rating Australia from New Zealand, and has extensively and permanently colo- nized the latter; the European Widgeon and Ruff have again and again been found in the middle and western United States, and the American Catbird has been taken in Italy. Examples of this erratic wandering, or apparently regular journeying, might be continued almost indefinitely, but enough has been given to show that the sea is not an insuperable barrier in all cases. New Zealand Region 29 It has been found possible to divide the land-masses of the world into a number of faunal (and floral) areas, each of which is more or less strongly charac- terized by the presence or marked absence of certain dominant or peculiar forms of life. The failure of early attempts at such delimitation was due, as already pointed out, to the effort to make them conform to the lines of political division, or to degrees of latitude and longitude ; and while naturalists are even now not in accord as to the number of primary divisions that should be recognized, Mr. P. L. Sclater was the first to put the subject on a scientific basis by applying to it a logical principle. The contention that "convenience, intelligibility, and cus- tom should largely guide us" in prescribing life areas has long been discredited, for it is now obvious that the mere size of an area can have no real weight so long as it is sufficiently characterized. It should not be inferred, however, that these life areas, whatever their size and grade, are always sharply circumscribed by hard and fast lines ; for while it is possible to define them with considerable definiteness in a general way, it rarely happens that a change from one to another is abrupt. Perhaps the most notable example of a sharp line of demarcation is that passing between the islands of Bali and Lombok and separating the Australian and Indian Regions. There is usually an area of greater or less width in which there is a commingling of the life forms of adjacent divisions, a neutral ground or transition area, as it is called. On the whole, however, it is found that these lines correspond quite closely to isothermal lines, or the lines of equal temperature. Sclater demonstrated that the surface of the globe exhibited six great divi- sions, each of which differed in a marked manner from all the rest, though the difference was not always equally important. These divisions, which he called Regions, are as follows: Palaearctic, Ethiopian, Indian, Australian, Nearctic, and Neotropical. For upwards of twenty-five years most writers on the subject accepted this classification with little change, though the conviction slowly gained ground that the distinction between the fauna of the northern portions of the Old and New Worlds was not as pronounced as had been thought. In 1893 Dr. J. A. Allen proposed a new classification, denominating the divisions of the first rank Realms, while those of second rank were called Regions, those of the third rank Provinces, of the fourth rank Subprovinces or Districts, and those of fifth rank Faunas. He recognized seven Realms: Arctic, North Temperate, American Tropical, Indo-African, South American Temperate, Australian, and Lemurian. In the same year Professor Alfred Newton proposed an arrangement which retained the number of Regions recognized by Sclater, but their outlines were very different. They are as follows: New Zealand, Australian, Neotropical, Holarctic, Ethiopian, and Indian, and while in some respects it seems somewhat less logical than Dr. Allen's, it is more conveniently followed here. The New Zealand Region. — There has been considerable discussion as to the propriety of considering this as a life area of primary rank, but notwith- standing the fact that it is by far the smaller of the areas usually so considered, it is sufficiently well characterized to warrant this distinction, and in fact cannot well be referred to any other Region. Regarding the matter of size it may be 30 The Geographical Distribution of Birds pointed out that while it is now restricted, if it is considered with relation to its dependent islands — Norfolk, Lord Howe's, and Kermadec Islands on the north, Chatham Islands on the east, and Auckland, Macquarie, and Antipodes groups on the south ->- which were once undoubtedly a part of it, it is seen that the area is but little short of that of Australia. This New Zealand area was set off from Australia by subsidence at a remote period, geologically speaking, and has apparently remained continuously separated. As might be supposed, this early separation and continuous isolation has resulted in developing or per- petuating some very remarkable life forms. It is, or rather was until recently, the home of two perfectly distinct orders of birds, the Dinornithiformes, or Moas, and their allies, embracing two families, some seven genera, and about thirty nominal species, and the A pterygiformes, or Kiwis, of which there are six species. The Australian Region. — This Region, says Newton, "has but little connec- tion with New Zealand and is as trenchantly divided from the Indian, which geographically, and possibly geologically, seems to be conterminous with it, by the narrow but deep channel that separates the small islands of Bali and Lombok, and will be found to determine the boundary between these two distinct Regions." Starting with an imaginary line between these two islands, we may trace it north- easterly, passing between Borneo and Celebes, and between the Philippines and the Pele w group. Thence the line proceeds northward to the vicinity of the Tropic of Cancer, and then eastward somewhat indefinitely so as to include the Hawaiian Islands, though these are perhaps more North American, but to include all of which is commonly called Polynesia, and return so as to encompass the New Caledonian Islands and of course Australia proper as well as Tasmania. Without going as extensively into the subject as is really warranted, it may be stated that the Australian Region is the exclusive home of the order Casuarii- formes, comprising the Cassowaries and Emeus, the superfamily Pseudoscines, which embraces the families Menuridce (Lyre-birds) and AtrichornithidcB (Scrub- birds), and the families Rhinochetid(B(Ka,gu\ Didunculida (Tooth-billed Pigeons), Loriidce (Lories), ParadiseidcE (Paradise-birds), and Ptilonorhynchidce (Bower- birds). In addition to these the following families are almost peculiar: Meli- phagida (Honey-suckers), Campephagida (Cuckoo Shrikes), Artamida (Wood- Swallows), CacatuidcB (Cockatoos), and Megapodidce (Mound-builders). As it is oftentimes nearly or quite as important to note the groups that are wanting in an area as it is to determine those which are present, it may be noted that the Australian Region lacks the families Vulturidce, (Vultures), Phasianidce (Pheas- ants), and PycnonotidcB (Bulbuls), to which should perhaps be added iheFringilli- d 33 34 The Migrations of Birds In the first place, it may be well to define briefly certain phases of bird move- ment that are often overlooked or confounded with the generally accepted under- standing of what migration covers. In the popular mind, and, it may be added, this is the correct view, a migratory species is one that regularly resorts to a given locality for the purpose of rearing its young, after which both old and young retire to some other, often widely different locality, where they pass the time before the next breeding season. In all temperate countries the migratory birds may be separated along these lines into two classes: first, those which come in spring, spend the summer, and retire towards autumn; and second, those which pass through in spring to a breeding ground nearer the pole, and in the fall while on their journey south. The distinction between these two classes is obviously one of degree rather than kind. The birds that come to us only in winter, such as Juncos, Snowflakes, Red- polls, and Lapland Longspurs, are not usually thought of as migrants, yet it requires but a moment's reflection to show that they are strictly so, and this leads to the general proposition that most birds throughout the world are con- stantly changing their location, but, as the individual is merged in the species, it is often difficult to obtain exact data on the subject. Because we see individuals of a certain species constantly about us, we call that a resident species, but, as a matter of fact, it is more than likely that not the same individuals are continuously under observation. There is also another class known as occasional visitors, as the Pine Grosbeak and Snowy Owl, which may be absent for years, then of a sudden appear in great numbers. Their coming is supposed to be the result of a deficient food supply in their natural habitat far to the north, but the evidence for this is theoretical rather than actual. Hardly to be distinguished from these occasional visitants are the sudden incursions of species in a locality in which they have never been before known, as when a vast horde of Nutcrackers spread over all Europe in 1844, or the erratic Sand Grouse, a bird of Central Asia, which has penetrated to England. But the climax of this restless and roving tendency in birds is reached in the stragglers that now and then are found hundreds, even thousands, of miles away from their homes, as when the Old World Skylark is found in Greenland and the Bermudas, the American Black-billed Cuckoo in Italy, and our Catbird and Brown Thrasher in Europe. While it may not b<* quite logical to class all these bird movements under the head of migration, as narrowly defined, they are more or less clearly manifestations of the same influences and go to make up the sum total of this wonderful ebb and flow of bird life. The origin, or perhaps better the origins, of this habit or instinct of bird migration is exceedingly obscure. Many theories have been advanced to account for it, but perhaps none has yet been offered that explains satisfactorily all its multitudinous phases. For instance, it has been suggested that migration is the result of the development or acquirement of the power of flight. That flight has had much to do in making long extended migrations easily possible no one can deny, but that it has been the cause is not logically evident, for certain mammals, as the bison and antelope, are to a limited extent migratory, and cer- Origins of Migration 35 tain flightless birds, as the Penguins and the Great Auks, are strictly so, or rather were in the case of the latter species which is now extinct. According to Mr. F. M. Chapman (" Bird Studies with a Camera," p. 194) "the desire for seclusion during the breeding season" is a "good and sufficient cause for the origin of bird migration." He applies this theory especially to birds nesting in colonies in secluded spots, as the Ipswich Sparrow, which is known to nest only on Sable Island, off the Nova Scotia coast, the Gannets (Sula bassana), which nest in the western hemisphere only on three islets in the Gulf of St. Lawrence, Terns on Muskeget and Penikese, and the Brown Pelicans of the Indian River region of eastern Florida. This theory may afford an explanation for the migrations of birds that con- gregate in such colonies during the breeding season, but it should not be over- looked that "survival of the fittest" may have been an equally important factor in weeding out those individuals of such colonies that did not seek these secluded or isolated localities for breeding sites. These birds may at first have nested in scattered situations and have been driven by predatory animals or other causes to seek inaccessible locations, and seclusion and isolation may thus have been a resultant rather than a cause. It is also difficult to apply this theory to land birds. Take, for example, the Warblers of the genus Dendroica. Some species barely reach the United States during the nesting season; a few stop in the south- ern tier of states; others only reach to southern New England, while the bulk of the species press on from northern New England to Hudson Bay. If seclusion were the only point aimed at, it would seem that the Warblers which pass farthest north to breed could have found it in the mountains of the southern and middle states as some now do. Again, certain species, as the Cliff and Barn Swallows, Phcebe and Summer Warbler, seek the vicinity of human habitations during the nesting season, and, moreover, have greatly increased in numbers since the country became thickly settled. The theory that is, perhaps, most naturally suggested, and the one that finds widest acceptance as explaining the facts, is that migration began in a search for food. That is, the food supply becoming short in the vicinity of the home (a bird's home is thus assumed to be the place where it rears its young, and may therefore be quite different from the locality where it spends the remainder of the time) they wandered away in search of food, returning again and again to the home vicinity. These journeys were extended farther and farther, the birds re- turning each nesting season, undoubtedly oftener at first, to or near the locality where they were born. This process went on until their wandering became a fixed habit, and finally in the countless generations of birds that have come and gone, this habit has been crystallized into what we now call, for want of a better term, the instinct of migration. This idea has been amplified and extended by Alfred Russel Wallace (Nature, X. 459). He supposed that "survival of the fittest" has probably exerted a powerful influence in weeding out certain individuals. He supposed further that breeding can only be safely accomplished as a rule in a given area, and that during a greater part of the rest of the year sufficient food cannot be 36 The Migrations of Birds obtained in that area. "It will follow that those birds which do not leave the breeding area at the proper season will suffer, and ultimately become extinct; which will also be the fate of those which do not leave the feeding area at the proper time." His further argument is ingenious, and, it must be added, extremely plausible. He says: "Now, if we suppose that the two areas were (for some re- mote ancestor of the existing species) coincident, but by geological and climatic changes gradually diverted from each other, we can easily understand how the habit of incipient and partial migration at the proper seasons would at last become hereditary, and so fixed as to be what we term an instinct." It will probably be found, however, if anything like a satisfactory explanation can be arrived at, that this habit or instinct has arisen in more than one way, but we may appropriately turn from a consideration of theories to a review of certain observed facts of migration. It is now abundantly established that migration is mostly carried on at night, and further mainly during clear nights. Only a comparatively few species, such as Ducks, Cranes, certain large Hawks, Swallows, Swifts, and Nighthawks, migrate during the daytime, and these, it will be observed, are either rapacious birds or mainly those that enjoy such power of rapid flight as to be relatively safe from capture. All the vast horde of Warblers, Sparrows, Finches, Fly- catchers, Thrushes, and Woodpeckers, as well as many waders and swimmers, migrate at night. On clear, still nights during the migrations birds may often be heard calling to each other high overhead, and, as will be described later, may be actually seen by powerful telescopes. Woods and hedgerows that were untenanted one day may become fairly alive with birds at daylight the next morning, showing that they have arrived during the night. They remain to feed and rest during the day, and, if the weather be favorable, may practically all disappear the next night. That they only venture on these journeys during clear nights is shown by the fact that on such nights very few birds are killed by lighthouses, monuments, or other obstructions, whereas on cloudy or rainy nights, especially such as opened clear and later become overcast, thousands of birds become confused and dash themselves against these obstructions. Thus over 1500 birds have been found dead at the base of the Bartholdi Statue in New York harbor in a single morning, and 230 birds of one species — Black-poll Warblers — were killed in a single night (September 30, 1883) by the Fire Island light. The Washington monument, although not illuminated at night, causes the death of hundreds of birds annually. The height above the earth at which migrating birds travel has been made the subject of some interesting observations, the first of which appear to have been by Mr. W. E. D. Scott, on the night of October 19, 1880, at Princeton, New Jersey. In company with a number of visitors he was being shown through the astronomi- cal observatory at that place, and after looking at a number of objects through the 9|-inch equatorial, they were shown the moon, then a few days past its full phase. His attention was at once arrested by numbers of small birds that could be more or less plainly seen passing across the field of observation. Most of the kinds seen were the smaller land birds, among which were plainly recognized Nocturnal Flight of Birds 17 Warblers, Finches, Woodpeckers, and Blackbirds. He was able to identify with much certainty the characteristic undulating flight of the Goldfinch, and the broad boat-shaped tail of the Purple Grackle. The flight of the birds noted was apparently nearly at right angles to the field of observation, and they were passing at the rate of 4^ per minute. As nearly as could be estimated their height above the earth was between one and two miles. In the following year similar observations were made by Scott and Dr. J. A. Allen, but the results were not as striking, only 13 birds passing in any quarter of an hour. They were also apparently flying lower than on the first occasion. Some years later observations on nocturnal flight were taken up by Mr. Chap- man, who spent three hours on the night of September 3, 1887, at Tenafly, New Jersey. During this time 362 birds passed across the moon's face. Of these 233 were computed to be at a height of from 1500 to 15,100 feet, and curiously the lowest birds seemed to be flying upward, as though they "had arisen in the imme- diate neighborhood and were seeking the proper elevation at which to continue their flight, but after that time the line of flight was parallel to the earth's surface." He was able to identify positively only comparatively few species, such as the Carolina Rail, Grackle, and a large Snipe. But perhaps the most satisfactory observations of all were those made also by Chapman, who, in company with a number of ornithologists, spent the night of September 26, 1891, at the Bartholdi Statue, New York. The weather proved to be exceptionably favorable, being clear during the early and later portions of the night, with an intermittent rain storm lasting for three hours between. As early as eight o'clock the birds began to be seen and heard, but almost simul- taneously with the beginning of the rain there occurred a very marked increase in the number of birds seen about the light. They came singly, in troops and in thousands, were visible for a moment and passed on into the darkness beyond. "The birds chirped and called incessantly. Frequently, when few could be seen, hundreds were heard passing in the darkness; the air was filled with the lisping notes of Warblers, and the mellow whistle of Thrushes, and at no time during the night was there perfect silence." Later recorded observations were made by Mr. O. G. Libby (Auk, XVI. 140), who studied the nocturnal migrations at Madison, Wisconsin, in September, 1897. His first place of observation was a small' elevation in the vicinity of three small lakes, where he undertook to make a record of the number of bird calls heard. During the night a total of 3800 calls were recorded. The number of calls varied greatly, sometimes running as high as two or three per second and again falling to that number per minute. The largest number counted was 936. From the nature of the data it was manifestly impossible to estimate the number of birds represented by these calls, but the effect was impressive in the extreme. He says: "Nothing but an actual experience of a similar nature can adequately convey the impression produced by such observations. The air seemed at times fairly alive with invisible birds as the calls rang out now faintly and far away, now sharply and near at hand. All varieties of bird calls came 38 The Migrations of Birds sounding out of the darkness that evening. The harsh squawk of a water bird would be followed by the musical chink of the Bobolink. The fine, shrill notes of the smaller Sparrows and Warblers were heard only close at hand, but the louder ones came from all along the line, east and west. More than once an entire flock, distinct by the variety of their calls, came into range and passed out of hearing, keeping up their regular formation with the precision of a rapidly moving but orderly body of horsemen. The great space of air above swarmed with life. Singly or in groups, large and small, or more seldom in a great throng the hurrying myriads pressed southward." The second station chosen by Mr. Libby was the Washburn Observatory, where for three nights he watched the birds passing across the face of the moon. During the three nights a total of 583 birds were counted, the largest number in any fifteen-minute period being 45. Considerable diversity in the direction of flight was noted. Thus up to ten o'clock the prevailing direction was south, but after this time the diversity increased, until it reached its maximum between twelve and two o'clock, when eight principal points of the compass were repre- sented by numbers varying from 3 to 28. However, two thirds of the number were still maintaining a southerly direction. Libby attempted to estimate roughly the total number of birds that passed his point of observation during the three nights, but as he well says, "when one recalls the relatively small size of the moon's surface as compared to its path from east to west, within the range of vision," the difficulty becomes evident. As nearly as could be made out, about 9000 birds were passing per hour, or a grand total of 168,000. The rate of speed at which birds travel during the migrations, and also at other times, has been made the subject of observation, although the results, as might be expected from the confusing elements which must enter into such an inquiry, are far from complete or satisfactory. If the speed often attained by powerful and swift-flying species, such as Ducks, Geese, Swallows, etc., could be maintained, it is obvious that the time occupied in migrations would be incon- siderable. But, as will be shown later, the maximum speed appears to be rarely or never realized at this time. Frank Forrester records 90 miles an hour for Ducks, as nojed by telegraph from point to point, and an Albatross has been known to cover 3150 miles in 12 days. The actual distance flown by the latter bird was probably at least twice as great, for they rarely fly far in a straight line. Some years ago Griffitt made some observations (recorded in The Field, Feb. 19, 1887) in a closed gallery on the speed attained by "blue-rock" Pigeons and English Pheasants and Partridges. The two first mentioned flew at the rate of only 32.8 miles per hour, while the Partridge made but 28.4 miles, and these rates were all considerably in excess of what they made in the open. The Carrier Pigeon is a rather fast flying bird, yet the average speed is not very great. Thus the average made in 18 matches (The Field, Jan. 22, 1887) was only 36 English miles an hour, although in two of these trials a speed of about 55 miles was maintained for 4 successive hours. In this country the average racing speed is Speed of Birds 39 apparently about 35 miles an hour, although a few exceptionally rapid birds have made short distance flight at the rate of from 45 to 52 miles an hour. One of the longest recorded flights of a Carrier Pigeon was from Pensacola, Florida, to Fall River, Massachusetts, an air-line distance of 1183 miles, made in 15^ days, or only about 76 miles a day. Herr Gatke, whose observations on Heligoland, a small island in the North Sea, extended over a period of fifty years, would give to birds a speed that is incredible. For example, the Gray Crows were believed by him to pass over the 360 miles between Heligoland and Lincolnshire at a rate of 120 miles an hour, and Curlews, Godwits, and Plovers are said by him to cross from Heligoland to the oyster beds lying to the eastward, a distance of a little more than 4 miles, in one minute, or at the astonishing rate of 240 miles an hour. The error in these observations, as suggested by Newton ("Dictionary of Birds," p. 566), probably lies in the impossibility of identifying the individuals that leave one of the given points with those first arriving at the other end of the line. Professor Newton also calls attention to the fact that few birds, even Swallows and Quail, fly as fast as an express train from whose windows they may be observed. It is a common experience, when a train is passing along at no great speed, for various birds to be flushed by it, but after flying vigorously for a few hundred yards they quickly drop behind. But granting that the occasional speed is very considerable, the actual speed of most migrating birds appears to be surprisingly low. Observations tending to prove this were made some years ago under the direction of Professor W. W. Cooke, in the Mississippi Valley. The services of over one hundred observers were enlisted, at stations ranging from the Gulf to Manitoba. The date at which a certain species was first noted at the most southern point was compared with the first appearance of that species at the most northern point; the distance in miles between these two stations is then divided by the number of days between the observations. Thus the Baltimore Oriole was first seen at Rodney, Missis- sippi, April 7, and was not observed at Oak Point, Manitoba, until May 25. The distance in a straight line between these two places is 1298 miles, and as it took 48 days, the average speed was 27 miles a day. The records of fifty-eight species for the spring of 1883 gave an average speed of 23 miles a day for an average distance of 420 miles, while in the following year a slightly smaller number of species gave exactly the same average speed over an average distance of 86 1 miles. In the case of individual species the results were of much interest. Thus the Robin, Cowbird, and Yellowhammer traveled at an average speed of about 12 miles a day, while the average for the Summer Redbird, Ruby-throated Hum- mingbird, and Nighthawk was 28 miles a day. It is, however, necessary to take so many things into account in arriving at these conclusions that it is easy to see the possibilities of error. For example, meteorological conditions play an important part during migrations; a rain storm or an unusually cold spell may retard progress for days. Even if the conditions are favorable, it is hardly probable that the same individuals migrate for more than a night or two without intermission, so that while the species may be making progress the individuals 40 The Migrations of Birds are alternating a night or two of travel with often several days of rest and recuper- ation. Again, it was found that most species traveled considerably faster during the latter part of the journey than during the first part. Thus six species showed an increase of 77 per cent in speed for the northern half of their journey, and the same general result was obtained by calculating the average speed of twenty-five species separately for each of the different months in which migration is per- formed; the average for March being 19 miles, for April 23 miles, and for May 26 miles a day. The species which are late migrants also move faster than those which start earlier and take more time about it. The persistence with which birds cling to established lines of travel during the migrations is one of the most remarkable facts within the range of bird life, and this in not a few cases can only be interpreted in the light of past geological conditions. Thus certain species which breed in Europe and spend the winter in Africa now cross the Mediterranean at one of the widest points, a seemingly needless waste of energy. But soundings between these points have shown that the sea for much of the distance is relatively shallow, and that a moderate sub- sidence has changed what may have been narrowest to what is now one of the broadest points. This subsidence was undoubtedly slow and first resulted in the formation of a series of islands and lagoons, and the birds easily passed from one island to another, and even after the last bit of land had disappeared they still followed the old route established by their remote ancestors. Many shore and water birds that spend the breeding season in and about the Arctic Circle to the north of Europe and Asia, follow lines of travel during their migrations that were undoubtedly established under past continental or oceanic conditions. Thus certain species take a circuitous route over what is now a wide expanse of open ocean, while others pass far inland through the Russian and central European lowlands. Those of the first class are simply still following an ancient shore-line, and those of the second class the location of an inland shallow sea. In other cases there is little evidence of former land connection, for many North American species, even of the smaller land birds, cross the Gulf of Mexico at its widest part. The Old World Migratory Quail (Coturnix coturnix} is one of the compara- tively few migrants among the so-called game birds. During the migrations they wander far from places of their birth, reaching South Africa* Persia, and India. The individuals inhabiting Great Britain, or at least a part of them, long ago established a migration route in a southeasterly direction. When examples from Great Britain were introduced into New England, they adapted themselves readily to their new surroundings and reared young, but when the season for migration arrived the inherited tendency to go in a southeasterly direction asserted itself, and, according to Mr. William Palmer, of the U. S. National Museum, they all passed out into the broad expanse of the Atlantic and were lost. For several decades it has been noted that a few species of birds from western Asia have been gradually extending their summer range into northern Scandinavia. When these species migrate, instead of going south through central Scandinavia or southwest along the coast-line, as do the original Scandinavian residents, Migration Routes 41 they turn back east to the point in Siberia whence they came, before turning southward to spend the winter on the borders of India. Forty or more species of migratory birds occur as summer residents in the Yukon Basin, Alaska. Of these some fourteen species are Pacific coast birds. With a single exception they are all thought to reach the upper Yukon by cross- ing the Alaskan coast range of mountains. This exception, according to Mr. W. H. Osgood, of the U. S. Biological Survey, is the Varied Thrush (Hesperocichla ncevia}, which apparently reaches its summer home by going up the coast to the lowlands below the mouth of the Yukon, and thence follows this river for almost 2000 miles. Equally abundant with it in this summer home is the common Snowbird (Junco hyemalis) of the eastern United States, which reaches the Yukon Basin by way of the Mississippi Valley. Perhaps the longest straight-away flight made during the migrations is ac- complished by certain shore and water birds, as the Tattler (Heteractitis incanus), Sanderling (Calidris arenaria) t Turnstone (Arenaria interpres), and the Pintail and Shoveler Ducks, which nest on islands in the Bering Sea and spend the winter in the Fanning and Hawaiian groups, a distance of some 2200 miles. As the shore birds above enumerated are probably unable to rest on the surface of the water, the entire distance must be accomplished in a single flight. It is difficult indeed to see how this line of migration could have been established. Following the analogy of the Old World species before mentioned whose path marks an ancient shore-line, we might presume that there was at one time a land connec- tion, or at least a chain of islands, between the Aleutian and Hawaiian groups, but on the contrary the depths of the Pacific are profound between these points, and there is not the slightest geological evidence on which to base a former land connection. When it is recalled how slight a deviation at the point of departure would suffice to throw them to the one side or the other of the Hawaiian Islands, the accomplishment is truly marvelous. In the absence of familiar landmarks and surrounded by a waste of sky and water, they make their way with the pre- cision of a rifle bullet. The Plovers, Sandpipers, and kindred species take migratory journeys often of extraordinary length. Thus the American Golden Plover (Charadrius domini- ons} breeds in Arctic America, some venturing a thousand miles north of the Arctic Circle, and migrates through the entire length of North and South America to its winter home in Patagonia, and curiously the spring and fall routes are very different. After feasting on the crowberry in Labrador they seek the coast of Nova Scotia, where they strike straight out to sea, taking a direct course for the easternmost islands of the West Indies, and thence to the northeastern coast of South America. In spring not one returns by this route, but in March they appear in Guatemala and Texas. " April finds their long lines trailing across the prairies of the Mississippi Valley; the first of May sees them crossing our northern boun- dary, and by the first week in June they reappear in their breeding grounds in the frozen North." The little Sanderling just mentioned is almost cosmopolitan in distribution, breeding in Arctic and sub-Arctic regions and migrating in the New World to Chile and Patagonia, a distance of 8000 miles, and in the 42 The Migrations of Birds Old World along all the shores of Europe, Asia, and Africa. The Bartramian Sandpiper (Bartramia longicauda) nests from eastern North America to Nova Scotia and Alaska, and goes south in winter to southern South America. The Solitary Sandpiper (fotanus solitarius) breeds mainly to the north of the United States and winters as far south as Brazil and Peru. The Buff-breasted Sandpiper (Tryngites subruficollis) rears its young in the Yukon district of Alaska and from the interior of British Columbia to the Arctic coast, and journeys in winter well into South America. The Turnstone (Arenaria inter pres), a little shore-bird about the size of the Song Thrush of Europe, is also cosmopolitan, breeding in high northern latitudes and at other times of the year being found along the coast of Europe, Asia, Africa, North America, South America to the Straits of Magellan, Australia, and the Atlantic and Pacific islands. It is one of the species mentioned as making the wonderful flight from islands in the Bering Sea to the Hawaiian Islands. The Ducks form another interesting group, although their journeys during the migrations are not nearly so extended as the birds just mentioned. The larger number breed mainly to the north of the United States and many within the Arctic Circle. Certain species, as the Eider Duck, only come south in winter to the coast of northern Maine, others, as the Old Squaw, may reach the Potomac and the Ohio, while most of them, as the Bald-pate, Blue-winged Teal, Pintail, Golden-eye, Bufflehead, etc., visit Mexico, Guatemala, northern South America, or the West Indies. Certain of the familiar birds of lawn, hedgerow, and field, for whose coming we watch so anxiously, may claim a moment's attention. The Bobolink, so dear to the hearts of the residents of New England, makes his appearance in his sum- mer home in May. By the last of July or the first part of August the young are reared, the old males have lost their bright dress, and with a musical chink as their only note, they start southward. In the region of the Chesapeake they begin to congregate in vast flocks, where they are known as Reed-birds, but in a few weeks they pass on to the rice fields of the South, to become the dreaded Rice-bird. But by October the last one has disappeared, and some by way of Cuba, others by way of Central America, where a few may linger, the main body presses onward beyond the Amazon into central and southeastern Brazil. On the return journey they reach the southern border of the United States in March arTd April. The Catbird is found in summer throughout the eastern United States and British Provinces, and in winter in the Southern States, Cuba, and middle America to Panama. Our common Robin is very erratic in habits of migration. Occa- sionally a few may winter in dense swamps as far north as southern Canada and Maine, but the majority spend the winter in the Southern States. The Chimney Swift is found in summer in eastern North America and thence north to Labrador and the fur countries. The winter is spent to the south of the United States. Cliff and Barn Swallows, which are found over nearly all North America in summer, may penetrate to Brazil, Paraguay, and the WTest Indies in winter. The Scarlet Tanager passes the winter in Central America and northern South America, and the familiar Indigo-bird may go as far as Panama. Sense of Direction in Birds 43 The great group of Warblers, of which some 70 species are found in the United States, has been mentioned before. They are all strongly migratory and mainly pass beyond our southern borders in winter, although a few individuals of a single species — the Yellow-rumped Warbler — have been known to winter on Cape Cod. Some of them visit the West Indies, but the larger number, after rearing their young in the dense coniferous forests of the Hudson Bay region or even in Alaska, spend the winter in Mexico, Central America, or northern South America. The Sparrows as a group are also strictly migratory. Quite a number, such as the Tree Sparrow (Spizella monticola), Snowflake (Plectra phenax nivalis), and Longspur (Cakarius lapponicus], breed far to the north of the United States in Arctic districts, and come down in winter into the Northern States or irregularly farther south. Many species which breed mainly north of the United States only go into the Middle and Southern States during the winter, while a few may reach the West Indies, Mexico, Central America, or northern South America. The Nighthawk is another example, some individuals spending the summer in Alaska and the winter in Patagonia, points separated by over five thousand miles, over which they must travel in spring and fall. But after having described these migration routes and the wonderful journeys over continents and vast oceans, the mystery of mysteries — How is it possible for the birds to find their way so unerringly ? — still remains without a wholly satisfactory answer. As in the case of theories propounded to account for the origin of migration, so numerous suggestions have been made to explain this wonderful faculty. Thus Dr. Von Middendorff, a distinguished naturalist who studied exhaustively the migrations in the Russian Empire, suggests that because all the spring movements in that country are toward the magnetic pole, the migrat- ing bird knows the location of this point and is enabled to direct its course accord- ingly. It is perhaps needless to say that this theory is not only unsupported by any serious data, but, as has been shown by Baird, is opposed to the facts of migration in North America. If during the migrations the older and stronger birds always led the way, it might be said with plausibility that this faculty is due in large measure to experi- ence, but here again the facts are either conflicting or directly opposed to such a view, for it seems to have been demonstrated with reasonable certainty that in Europe the young birds not only precede the old, during the fall movement, but often travel by a wholly different route. In this country, however, observations on this point are limited and authorities differ, but the tendency is to believe that the old birds do actually lead. Observation is much needed to settle this question. In the case of birds migrating over land areas, sight is supposed by some to have an all-important function, especially when it is recalled that a bird two miles above the earth is surrounded by a horizon line of 90 miles on either side. As already shown, they have been observed at a height of three miles, which would easily keep them within sight of prominent landmarks, and would even permit them to cross considerable bodies of water without entirely losing themselves. That they depend to some extent on such landmarks to guide them on their 44 The Migrations of Birds course seems to be shown by the fact that they migrate mainly on clear nights and are obliged to seek the earth on the approach of cloudiness and storms. But in the case of birds migrating over hundreds or even thousands of miles of open water, vision must play an unimportant part. Mobius (Das Ausland, August, 1882) suggests that in such cases they may be guided by observing the roll of the waves, but while this may be true in a few instances, it cannot possibly be so in the majority of cases. As an example of this power of orientation it may be mentioned that the members of the Harriman Alaska Expedition went by steamer from the island of Unalaska to Bogoslof Island, a distance of some 60 miles. "A dense fog had shut out every object beyond a hundred yards. When the steamer was halfway across, flocks of Murres, returning to Bogoslof after long quests for food, began to break through the fog-wall astern, fly parallel with the vessel, and disappear in the mists ahead. By chart and compass the ship was heading straight for the island; but its course was no more exact than that taken by the birds." — COOKE. We therefore seem inevitably led to the conclusion that birds are possessed of a "sense of direction." This "homing" faculty or power of orientation, which is, for example, so strongly developed in the Carrier Pigeon, is by no means unique among birds. It is possessed in a greater or less degree by many animals, by most savage races of men, and not infrequently by individuals among civilized races, more especially those accus- tomed to life away from centers of civilization, in forest and on plain, — just how it is to be explained is difficult to say. Some would give it the dignity of a sixth sense and would fix its seat in the semicircular canals of the ear. CHAPTER V THE CLASSIFICATION OF BIRDS LASSIFICATION is the orderly grouping together of those beings or things that have certain characteristics in common. Zoological classi- fication, therefore, is the grouping together of animals in accordance with their affinities and interrelationships so far as these have been ascertained, and consequently avian classification is an attempt to express, as nearly as present facts warrant, the lines along which it is supposed the birds have been developed. It may be regarded as the higher phase of ornithological study, requiring for its successful prosecution the widest knowledge, the keenest discrimi- nation, and the most careful interpretation. The only satisfactory manner in which such a classification can be graphically displayed is by means of a so-called genealogical tree, the trunk and limbs of a tree, as it gradually divides into smaller and smaller branches, illustrating well the manner in which groups of birds are assumed to have developed, each from an earlier or ancestral stock. It is obvi- ously impossible to show this relationship by arranging them in a linear sequence, although the exigencies of book making may render such disposition necessary. A linear arrangement may go well for a short distance, one group following another in an apparently natural succession, but sooner or later a point is reached where it is necessary to begin again at the base of another branch or stem, and so in the system of classification here adopted it is not necessarily to be presumed that each group is always related in equal degree to that which immediately precedes or follows it. I have already pointed out that, although the Class of Birds is not sharply circumscribed by what may be called essential characters, the fact that they alone possess an outer covering of feathers makes their recognition easy under any and all circumstances. There can never be any doubt in the popular mind about the identification of a bird as such, a condition far from being true in many other coordinate groups of the animal kingdom. For present purposes, there- fore, the Class of Birds may be said to be clearly differentiated, but when we come inside the Class a wholly different state of affairs is presented, for there is perhaps no group of similar scope in which the members are relatively so uniform in structure and appearance as are the birds. Their classification is thus nat- urally beset with many difficulties. As Mr. Ridgway well says : " Accepting evo- lution as an established fact, — and it is difficult to understand how any one who has studied the subject seriously can by any possibility believe otherwise, - there are no 'hard and fast lines,' no gaps, or 'missing links' in the chain of 45 46 The Classification of Birds existing animal forms except as they are caused by the extinction of intermediate types; therefore there can be no such group as family or genus (or any other for that matter) unless it is cut off from other groups by the existence of such a gap; because unless thus isolated it cannot be denned, and therefore has no existence in fact. These gaps being very unequally distributed, it necessarily follows that the groups thus formed are very unequal in value ; sometimes alternate links in the chain may be missing; again, several in continuous sequence are gone, while occasionally a series of several or even numerous links may be intact. It thus happens that some family or generic groups seem very natural and homogeneous, because the range of generic or specific variation is not great and there is no near approach to the characters of another coordinate group, while others may seem very artificial or heterogeneous because among the many generic or specific forms none seems to have dropped out, and therefore, however great the range of varia- tion in structural details, no division into trenchant groups is practicable, — not because extreme division would result, but simply because there can be no proper definition of groups which do not exist. In short, no group, whether of generic, family, or higher rank, can be valid unless it can be defined by characters which serve to distinguish it from every other." Bearing these limitations in mind, it is not hard to understand the difficulties in the way of an acceptable classification of birds, but these obstacles should in no wise deter us from the attempt ; nor have they, for the pathway of ornitho- logical literature is strewn with them. Hardly any two students will be found in agreement in all particulars, and from the primary division of the Class to the faintest subspecies there may be almost every shade of opinion. As an example of these difficulties of treatment the primary division of the Class may be cited. To go no farther back than the promulgation of Huxley's celebrated " Classifica- tion of Birds," published in 1867, wherein he divided the Class Aves into three principal groups which he denominated Orders: Garrod in 1874 recognized but two primary divisions, which he called Suborders, as did Sclater in 1880, although neither included the Toothed-birds and their immediate allies. The forms admitted under the " Suborders" are also very different in the two latter systems. In 1884 Newton adopted the divisions of Huxley, but called them more appro- priately Subclasses, while about the same time Reichenow proposed a scheme in which, exclusive of the Toothed-birds, he recognized no less* than seven primary " Series." The next in order is Stejneger, who in 1884 divided the Class into four Subclasses. This number was reduced to two in the scheme of Gadow (1888), while Sharpe in 1891 returned to the three divisions of Huxley and Newton. Ridgway in 1901, in working out a plan of classification for his " Birds of North and Middle America," has found it expedient to adopt, tentatively, the two divisions of Gadow. Examples of this difference of opinion might be multiplied almost indefinitely, but I will take the space for but one more. The Order Passeriformes, or so- called higher birds, embraces fully seven thousand species and subspecies, "or more than one half of all existing birds." Gadow in his plan for dividing them says it is possible to recognize no more than three families in all this vast The Classification of Birds 47 assemblage that will rank with the families of other groups, whereas Sharpe recognizes among them forty-nine families. "Surely," as Ridgway says, "be- tween these extremes there is ample room for differences of opinion and variety of treatment !" In attempting to select a scheme of classification to be followed in arranging the various parts of this work, I have been presented, so to speak, with the two horns of a dilemma. In the first place it is hardly to be presumed that many readers will have more than a passing interest in all the intricacies and finer problems of bird classification. The external appearance of birds, their habits of life and conduct in their multitudinous details, will be, I assume, the main points of attraction to most readers. To such any fairly consecutive arrange- ment might prove reasonably acceptable, especially when it is recalled that the state of the science is not now, nor will it apparently be for many a long year, in position to permit anything like a final classification of birds. But, on the other hand, it seems neither logical nor just to select an antiquated system when it is perhaps as easy to adopt one embodying the results of modern research along this line. Therefore the classification which I have finally adopted represents, so far as I have been able to make it, an attempt at defining the present status of knowledge regarding the affinities within the Class Aves. It is in the main the classification of Gadow, but has been modified in several minor particulars to accord with the later researches of Pycraft, Beddard, D'Arcy-Thompson, Shufeldt, Ridgway, Lucas, and other well-known author- ities. That this classification or any other will meet with the approval of all systematists is hardly to be expected. I make no special claim for originality; it is simply a putting together of facts from many sources in the hope that it may prove a fairly acceptable arrangement. OUTLINE OF CLASSIFICATION OF BIRDS ADOPTED IN THIS WORK Class AVES Subclass I. ARCH^ORNITHES Archseopteryx Subclass II. NEORNITHES Order I. HESPERORNITHIFORMES Hesperornis Order II. ICHTHYORNITHIFORMES Ichthyornis Order III. STRUTHIONIFORMES Ostriches Order IV. RHEIFORMES Rheas Order V. CASUARIIFORMES .... Cassowaries and Emeus Order VI. CRYPTURIFORMES Tinamous Order VII. DINORNITHIFORMES ... . Moas Order VIII. JEPYORNITHIFORMES ... . Elephant-birds Order IX. APTERYGIFORMES . . Apteryx The Classification of Birds Order X. SPHENISCIFORMES Family Spheniscidae Order XL COLYMBIFORMES Suborder COLYMBI Family Gaviidae Suborder PODICIPEDES Family Podicipedidge Order XII. PROCELLARIIFORMES Family Diomedeidae Family Procellariidae Family Pelecanoididae Order XIII. CICONIIFORMES . Suborder STEGANOPODES Family Phaethontidae Family Pelecanidae Family Phalacrocoracidae Family Anhingidse Family Sulidae Family Fregatidae . Suborder Family Ardeidae Family Cochleariidae Family Balaenicipitidae Family Scopidae Suborder CICONI/E Family Ciconiidae . Family Ibididae Family Plataleidae . Suborder PHCENICOPTERI Superfamily Phoenicopteridae Order XIV. ANSERIFORMES Suborder PALAMEDE^ Family Palamedeidae Suborder ANSERES Family Anatidae Order XV. FALCONIFORMES . Suborder CATHART^ Family Cathartidse Suborder GYPOGERANI Family Gypogeranidae . Penguins Penguins Loons and Grebes Loons . Grebes . Albatrosses and Petrels Albatrosses . Petrels Diving Petrels Stork-like Birds . Tropic-birds Pelicans Cormorants Snake-birds . Gannets . Frigate-birds . Herons Spoon-bills Shoe-bills Umbretta Storks Ibises Spoon-bills Flamingos •» Goose-like Birds Screamers Swans, Geese, and Ducks Falcon-like Birds . American Vultures Secretary-birds The Classification of Birds 49 Suborder ACCIPITRES . Family Falconidae . Family Buteonidae . Order XVI. GALLIFORMES Suborder MESCENATIDES Family Mescenatidae Suborder TURNICES Family Turnicidae Family Pedionomidse Suborder GALLI Family Megapodidae Family Cracidae Family Phasianidae Suborder OPISTHOCOMI Family Opisthocomidae Order XVII. GRUIFORMES . Family Rallidae Family Gruidae Family Cariamidre Family Otididse Family Rhinochetidae . Family Eurypygidae Family Heliornithidae . Order XVIII. CHARADRIIFORMES I. LARO-LIMICOL^: Suborder LIMICOL^ Family Charadriidae Family Chionididse Family Dromadidae Family Glareolidse Family Thinocoridae Family (Edicnemidae Family Jacanidae . Suborder LARI Family Laridae Family Alcidae II. PTEROCLO-COLUMB.E Suborder PTEROCLES Family Pteroclidae . Falcons Kites, Ospreys, Eagles, Vultures, Harriers, etc. Fowl- like Birds Madagascar Kagu or Mesite . Bustard Quails, or Hemipodes Collared Hemipodes Megapodes, or Mound-builders Curassows Turkeys, Partridges, Quails, Pheasants, etc. Hoactzin Crane-like Birds Rails Cranes, Courlans, and Trumpeters . Cariamas . Bustards Kagu Sun-Bitterns Sun-Grebes or Finfeet Plover-like Birds Plovers, Snipes, and Curlews Sheath-bills Crab Plovers . Pratincoles and Coursers Seed-Snipe Thick-knees Jacanas Gulls, Terns, and Skimmers Auks Sand Grouse 5° The Classification of Birds Suborder COLUMB^ Family Dididae Family Columbidse Order XIX. CUpULIFORMES . Suborder CUCULI Family Cuculiclae . Family Musophagidse Suborder PSITTACI Family Trichoglossidse . Family Psittacidse Order XX. CORACIIFORMES . Suborder CORACLE Family Coraciidae . Family Momotidae Family Alcedinidae Family Meropidae . Family Bucerotidae Family Upupidas . Suborder STRIGES Family Strigidae Suborder CAPRIMULGI Family Steatornithidae . Family Podargidse Family Caprimulgidge Suborder MICROPODII Family Trochilidse Family Micropodidae Suborder COLII Family Coliidae Suborder TROGONES Family Trogonidae . Suborder PICI Family Galbulidae . Family Capitonidse . Family Rhamphastidse . Family Picidse Order XXI. PASSERIFORMES . Suborder DESMODACTYLI Superfamily Eurylaimidse . Dodo and Solitaire Pigeons Cuckoo-like Birds Cuckoos . Plantain-eaters Nestors, Lories, False Lorikeets, etc. Cockatoos and Parrots Roller-like Birds Kirumbos and Rollers Motmots and Todies Kingfishers Bee-eaters . Hornbills . Hoopoes Owls . Oil-birds Frogmouths Goatsuckers . Hummingbirds Swifts Colics •* . Trogons . Puff-birds and Jacamars Barbels and Honey-guides . Toucans Woodpeckers and Wrynecks Sparrow-like Birds Broad-bills The Classification of Birds rj Suborder ELEUTHERODACTYLI Superfamily Clamatores Family Pittidae Pittas Family Philepittidae Asities Family Xenicidae Rifleman and New Zealand Wrens Family Oxyruncidse . .... Sharp-bills Family Tyrannidae . ... Tyrant-birds Family Pipridse . .... Manakins Family Cotingidae . .... Chatterers Family Phytotomidae . ... Plant-cutters Family Dendrocolaptidae ...... Wood-Hewers Family Furnariidae . ...... Oven-birds Family Formicariidae ........ Ant-birds Family Conopophagidae Ant-pipits Family Pteroptochidae . . . . . . . Tapacolas Superfamily Pseudoscines Family Menuridae Lyre-birds Family Atrichornithidae Scrub-birds Superfamily Oscines Singing-birds Family Alaudidae ...... . Larks Family Motacillidae . . . . . . Wagtails and Pipits Family Enicuridae ........ Fork-tails Family Timeliidae Babbling Thrushes Family Pycnonotidae Bulbuls Family Muscicapidae Flycatchers Family Turdidae Thrushes Family Zeledoniidae Wren-Thrush Family Mimidae Mockingbirds Family Cinclidae Dippers Family Troglodytidae Wrens Family Chamaeidae Wren-Tits Family Sylviidae Old World Warblers Family Regulidae Kinglets Family Hirundinidae Swallows Family Campephagidae ...... Cuckoo-Shrikes Family Dicruridae ........ Drongos Family Ampelidaa Waxwings Family Ptilogonatidae Silky Flycatchers Family Dulidse Palm Chats Family Artamidae Wood-Swallows Family Vangidae Vanga-Shrikes Family Laniidae Shrikes Family Prionopidae ....... Wood-Shrikes Family Aerocharidae Helmet-birds 52 The Classification of Birds Family Vireonidae ........ Vireos Family Sittidae ........ Nuthatches Family Hyposittidse Coral-billed Nuthatch Family Paridae Titmice Family Orjolidae . Orioles Family Ptilonorhynchidae ...... Bower-birds Family Paradiseidae ...... Birds-of-Paradise Family Corvidse Crows and Jays Family Sturnidae ........ Starlings Family Eulabetidae Glossy Starlings Family Meliphagidae ....... Honey-eaters Family Zosteropidae ........ White-eyes Family Nectariniidse . Sun-birds Family Dicaeidae ....... Flower-peckers Family Certhiidse Creepers Family Crerebiclae Honey-creepers Family Drepanididae ..... Hawaiian Honey-creepers Family Mniotiltidae ....... Wood- Warblers Family Tanagridaa ........ Tanagers Family Ploceidae Weaver-birds Family Icteridae ........ Troupials Family Procniatidse ...... Swallow-Tanagers Family Catamblyrhynchidae .... Plush-capped Finches Family Fringillidae Finches CHAPTER VI THE ARCH^OPTERYX, OR LIZARD- TAILED BIRD (SUBCLASS Arch&ornithes) | EOLOGICAL Occurrence. — The oldest bird of which we have any knowledge, called the Archaopteryx, or Lizard-tailed bird, the latter name from its slender lizard-like but curiously feathered tail, is found fossil in the lithographic slates of Solenhofen, Bavaria, where its presence was first made known by the discovery in 1861 of the impression of a single feather. The existence of a bird in a geological horizon of such rela- tively great antiquity as this — Upper Jurassic — was at first somewhat doubted, but a year or two after the first discovery a second specimen, showing much of the skeleton, was obtained, and in 1877 another, these being all thus far secured. The ex mple found in 1863 is now preserved in the British Museum, London, while the last, and as it proves, best example, is in the Berlin Museum. These two specimens, which are sometimes regarded as representing two distinct species (Archaopteryx lithographica and A. siemensi], supplement each other, and from them a fairly complete account may be gleaned of this remarkable bird. They have been very minutely studied by many eminent anatomists, as becomes their importance in affording almost our only actual knowledge of the transition between reptiles and birds. Anatomy, Size, etc. — The Lizard-tailed bird was apparently about the size of our common Crow, being nearly eighteen inches in length. It had appar- ently a long, narrow body, while the head was small, pyramidal, nearly flat on top, and provided with large openings for the eyes. The upper jaw, and prob- ably the lower as well, was provided with numerous teeth, which appear to have been set in a groove. There was no beak, for the teeth extended to the very tip of the jaw. The backbone consisted of some fifty biconcave vertebrae, of which number ten or eleven are regarded as belonging to the neck, a less number than is known in any modern bird, the lowest number being thirteen. In place of the short, usually solid bones of the tail found in present birds, Arch&opteryx had a long, slender tail of about twenty free bones exactly as in many reptiles. Certain of these bones, perhaps each of them, supported a pair of long tail feathers. These .feathers at present lie at an angle of about thirty degrees to the bones of the tail, and as they are pretty closely matted together, it is difficult to determine the exact number, some students placing them at twenty pairs, and others, as Gadow, as low as twelve pairs; the truth perhaps lies some- 53 54 The Archaeopteryx, or Lizard-tailed Bird where between these extremes. Present knowledge does not permit a positive assertion that the tail could be raised or depressed at will, or the pairs of feathers spread or closed, though both conditions might readily have been possible, for a very small tendon would have been ample provision for the manipulation of these parts without any trace of its presence appearing on the bones. ArdicEopteryx had four toes, and the whole leg and foot appeared very much like those of an ordinary perching bird, except that the tibia and fibula were distinct, as in most reptiles. The anterior limbs, however, are very curiously modified. The wings were rather short and rounded very much as in the com- mon fowl, but unlike all known birds there were three long, slender fingers on each wing, each of which was armed with a hooked, sharp-edged claw. There were also relatively large flight feathers, the apparent number being seventeen in each wing, six or seven of which were primaries and the rest secondaries, and, it may be added, no other bird has so few primaries. In addition to the quills there was at least one row of wing-coverts. The sternum, or breast-bone, is obscurely preserved and is more or less in doubt, some observers claiming that it is not only present but possesses a well- defined keel, while others declare that, although much has been written about it, nothing is absolutely known. A definite knowledge of this bone would be of great assistance in interpreting the probable habits of its owner. The three bones of the pelvis, as in most reptiles, are perfectly distinct from one another, and a further decidedly reptilian character is found in the absence of the hook- like processes of the ribs. The covering of the body, aside from the wing and tail feathers, has been the subject of much speculation. From the fact that the feathers of tail and wings are preserved with such remarkable fidelity, it is argued that, had there been a general feather covering, some definite trace of it would remain. As it is, the only positive contour feathering seems to be confined to the leg, producing apparently a "booted" condition similar to that observed in the Falcons. There is also some slight evidence of the presence of a "ruff" about the base of the neck, as in the Condor, while the remainder of the body was apparently naked, or pos- sibly covered with down or small feathers which disappeared during the decay which preceded the entombment. The contention advanced by certain writers that the body, aside from the feathering mentioned above, was covered with scales is not only absolutely unsupported by fact, but is in the highest degree improbable. The length of time that must have intervened in evolving the very perfect wing and tail feathers of Archtzopteryx from reptilian scales, if that is whence they came, would undoubtedly have been ample for the production of some sort of a feather covering for the remainder of the body. Probable Habits. — With the above facts before us we are perhaps in posi- tion to indulge in some fairly reasonable speculation as to the habits of this ancient bird. From the presence of a distinctly perching foot it may be inferred that a considerable portion of its life was spent in trees, which are known to have been abundantly present at that time, and further, that the curious hooked fingers were of assistance in climbing about among the branches, as are those of Probable Habits 55 a young Hoactzin of to-day. On account of the relative slenderness of both legs and feet, and to their position far back on the body, Mr. Beddard, a dis- tinguished English anatomist, doubts if the Archceopteryx could have stood erect. On the ground he thinks it must have assumed a quadrupedal position. In support of the opposite view it may be stated that the tips of the wing-quills are not worn or injured, as they almost certainly would have been had they habitu- ally come in contact with the ground. But this is a point that obviously cannot be definitely settled. The fact that no openings have been observed for the admission of air into the bones has been taken by several writers to militate against flight. This is certainly a very unsafe generalization, for, as already pointed out, certain birds, as for example the Swallows, that are past masters in the art of flying, have prac- tically non-pneumatic bones, while others, as the Ostriches, have the bones highly pneumatic, yet cannot fly at all. Although the wings were rather short and rounded, the well-developed wing feathers, which appear adequate for the support of a bird of this size, seem to indicate beyond reasonable doubt that Archceopteryx could fly, though perhaps it was incapable of long-sustained flight. The Tinamous furnish an example in point. They have short, rounded wings and can fly well for short distances, but soon become exhausted. If we possessed a more satisfactory knowledge of the breast-bone, we should be the better able to decide regarding the probable power of flight, for if this was actu- ally absent or very much reduced in size, it would appear to militate against the enjoyment of any great power of aerial locomotion. It may be added, as was pointed out by Professor Lydekker, that the slight development of the delto- pectoral crest of the humerus apparently indicates at least weak power of flight. As to the food of the Arch&opteryx we of course know nothing, but from the presence of the numerous distinct and rather sharp teeth it may be inferred that these were still of assistance in procuring food, which likely consisted of animals of some kind. But this is largely speculation. All things considered, Archceopteryx was a most remarkable animal. While it possessed numerous points of structure unmistakably similar to those of reptiles, it was, on the whole, much nearer to the birds than to the reptiles. It is clearly a connecting link between the two classes, and yet we are undoubt- edly still very far from the original point where the branch was made from the reptilian stem. Indeed, the reptiles as we know them may be very unlike what they were when the division occurred which ended in Archceopteryx on the one hand and modern reptiles on the other. In any event it must have taken a very long period of time for the development of such distinctly bird-like feet and featners. Arch&opteryx is well entitled to be placed in a Subclass, opposed to all other known birds. In 1 88 1 Professor O. C. Marsh described, under the name of Laopteryx prisons, a crushed and broken skull and a single detached tooth that may or may not have belonged to it, from the Jurassic beds of Wyoming. This has been supposed to be the skull of a bird, and, for no other reason than that it is found in beds of similar geological age, has sometimes been placed in the Subclass with Archaopteryx. It now seems more than likely that it will be proved to belong to the reptiles, and in any case too little is known of its structure to definitely associate it with Archaopteryx. CHAPTER VII THE AMERICAN TOOTHED-BIRDS (SUBCLASS Neornithes) (Orders Hesperornithiformes and Ichthyornithiformes) \ N point of time the next birds of which we have any knowledge, in the line of evolution between the Lizard-tailed birds and those of the pres- ent, are the so-called American Toothed-birds, the remains of which came to light some thirty or more years ago in the Cretaceous rocks of western Kansas. If it is true, as has been stated, that the bird-like elements in Ar- chaopteryx amount to three fourths, and the reptilian features to no more than one fourth, of its make-up, then the Toothed-birds, although presenting a number of anomalous characters, are perhaps entitled to be called nine tenths "bird, "for they exhibit a very distinct advance over the Lizard-tailed birds, which brings them in some respects quite close to if not indeed fully abreast of modern birds, and this be it remembered at a time so remote as the Cretaceous period. As the name implies, their most marked characteristic is the possession of distinct teeth, a character which they share in common with the Archaopteryx, but which sharply distinguishes them from all other known birds, either fossil or living. The man- ner in which the teeth are implanted in the jaw, as well as modifications of the skeleton which have resulted from very different modes of life, serve as a basis for dividing the Toothed-birds into very distinct groups which are thought to be of sufficient importance to rank as separate orders. Hesperornis. — The first of these orders to be considered is typified by what has been named the Hesperornis, signifying literally "western bird," since at the time of its discovery the locality where it was found was beyond the western limits of extensive settlement. Hesperornis was a flightless, swimming and diving bird of great size, its length being nearly four feet. The skull was rela- tively small, while the bill or jaw was very long and slender, with its rami or branches united in front by a ligament only, and the component bones free from one another, as in reptiles. The teeth, which were replaced by a new one grow- ing inside of and ultimately absorbing and pushing off the old one, are set in a continuous groove, and fill the lower mandible quite to the tip, while in the upper mandible they are confined to the basal portion or maxilla. The long and slender neck is made up of some seventeen saddle-shaped vertebrae, and was doubtless capable of rapid flexure and was thus of assistance in securing its prey. The wing was very much reduced, being represented by the humerus only, and was probably concealed beneath the skin or in any event among the 56 Hesperornis 57 feathers. Without going into a complete description of the shoulder girdle it may be said that its elements, as interpreted in the light of recent material, make it very similar to the arrangement found in recent birds and not nearly so similar to the reptiles as was formerly supposed, and further, the struthious characters are also decidedly less apparent than was believed. The body or pelvis was greatly compressed, while the legs and feet present some anomalous features. The femur was short and stout, the tibia very long and slender FlG. 20. — Hesperornis regalis. Skeleton in U. S. National Museum from which the restoration (Fig. 21) was made. Sternum and two anterior cervicals supplied by restoration. (Lucas.) although somewhat pneumatic, the fibula slender, about three fourths the length of the tibia, and united to it by a cartilage only, while the metatarsus was rela- tively short and stout. The feet were four-toed, the outer toe being much the largest, and nearly twice the length of the third toe. Mr. F. A. Lucas was the first to call attention to the fact that the legs of Hesperornis were directed out- ward almost at right angles to the body, instead of downwards as in other birds, and that apparently they were naturally moved together like a pair of oars. There is also evidence to show that the toes were webbed as in the Grebes. This peculiar arrangement of the legs, combined with the almost total absence of wings, must have made this bird practically helpless on land, to which it doubt- less resorted as rarely as possible, and then only for nesting purposes. The American Toothed-birds Some years ago Professor Williston discovered a fragmentary specimen which he thinks represents the plumage of Hesperornis, and if this is correct, it was covered with long, fluffy, hair-like feathers, which has been taken as another indication of its relationship with the Ostrich-like birds. This sort of plumage is seemingly but a poor adaptation for aquatic life, yet it is not wholly without parallel among recent birds, such for example as the Snake-birds (Anhinga), which are covered with a very loose and easily water-soaked feathering. The life habits as interpreted by the structure, indicate that Hesperornis was carnivorous, feeding doubtless upon the fishes and other aquatic life that FIG. 21. — Restoration of the great toothed diver of the Cretaceous, Hesperornis, by Gleeson. (From Lucas's "Animals of the Past," by permission of the publishers, McClure, Phillips & Co.) is known to have been abundantly present in the Cretaceous seas. Its narrow body and powerful legs and webbed toes point to its having been an expert swimmer and diver, enabling it to overtake its finny prey, in which it was assisted also by its long flexuous neck and numerous sharp, backward-pointing teeth. As might be supposed the relationship of this remarkable bird has been the subject of much discussion and not a little difference of opinion, and so long as certain important parts of the skeleton remain unknown, its exact position must remain open to more or less question. It was at first regarded as a carnivorous, swimming Ostrich, but as already suggested, the structure does not at all bear out the claim of its struthious affinity, and moreover, as there is no authentic trace of the presence of the Ostrich in North America, this may be dismissed at once (cf. p. 63). By many it is regarded as being closely allied to, if not indeed the direct ancestor of, the Loons and Grebes, but as Mr. Lucas has very clearly shown, those portions of the skeleton which are thought to indicate kinship with the Loons and Grebes are only similarities of structure which have resulted from Ichthyornis eg similarity of habits. And, as he has further pointed out, the anomalous con- dition would be presented of placing the strong-flying Loons and Grebes in the direct line of descent from a flightless bird, which would be "quite out of the question." All things considered it would appear that Hesperornis was in many respects a very highly specialized type which has been blotted out without leaving any close relatives among living birds. Other Forms. — In the same beds with Hesperornis regalis, the form above mentioned, two additional species of Hesperornis were described, one of which has recently been removed as the type of a new genus (Hargeria), and another wholly different flightless swimming bird known as Baptornis, or the "plung- ing bird," in allusion to its probable diving habits. These are all imperfectly known, and a full descrip- tion may be omitted. Ichthyornis. — The second order of Toothed- birds (the Ichthyornithi- formes) differs essentially from the first, as already mentioned, in having the numerous teeth implanted in distinct sockets. They take their name from Ichthy- ornis, the principal genus, which signifies "fish bird," from the fact that the ver- tebrae are of the same shape as in fishes. Although a dozen or more nominal species have been described, disposed among five more or less tentative genera, the group is still imperfectly understood. Of the various members Ichthyornis victor is best known and may be selected for brief description. It was a much smaller bird than Hesperornis, being about the size of a common Pigeon, and was clearly a very powerful flyer. The head was relatively much larger than in Hesperornis, but the disposi- tion of the teeth was the same in both, and the component parts of the mandibles were likewise distinct. The teeth were all sharp and pointed, more or less compressed, and strongly recurved, and were placed vertically as in the crocodiles and certain extinct lizards. The exact number of vertebrae FlG. 22. — Ichthyornis victor, a Cretaceous Toothed-bird of flight, £ natural size. (Restored by Maish.) 60 The American Toothed-birds in the neck is not known, but from the large number found it is presumed that they were numerous, and that the neck was relatively long and slender. The undoubted strong power of flight enjoyed by Ichthyornis is well indicated by the shoulder girdle and wings, these conforming strictly to the type seen in strongly keeled living oirds, and as has been said, "might have been used by some existing birds with strong powers of flight." The legs and feet are of small size and present no particular features that may not be observed in modern flying birds. The following account of the probable mode of life and habits of Ich- thyornis is from Marsh, the original describer of the bird: "The sharp cutting teeth of Ichthyornis prove, beyond a doubt, that it was carnivorous; its great power of flight, long jaws, and its recurved teeth suggest, moreover, that it cap- tured its prey alive. Its food was probably fishes, as their remains are found in great abundance mingled with those of Ichthyornis. These fossils occur in the bed of the old Cretaceous ocean in which Hesperornis swam. Both of these birds were clearly aquatic in habit, as shown by various points in their structure, and the conditions under which their remains were deposited. In many respects, Ichthyornis probably resembled the modern Terns in its mode of life. The powerful feet and wings suggest similar habits in flight and rest." The affinities of Ichthyornis are almost as much in question as those of Hes- perornis. By some it is regarded as being nearest to the Terns and especially the Skimmers, by others it is relegated to the vicinity of the Storks and Plovers, while still others would place it between the Ducks and Accipitres. The truth of the matter is its structure is still too imperfectly known to venture a positive opinion, and even if we were familiar with all the details of its anatomy, it is probable that its direct relationship with modern birds would still be as difficult to establish, for it appears to have belonged, together with its allies, the other Toothed-birds, to a group that represents one link in the chain of succession between reptiles and present birds. CHAPTER VIII THE OSTRICHES (Order Struthioniformes) T is perhaps needless to say that the Ostriches are the largest of existing "birds, a fully matured individual standing some eight feet in height and weighing quite three hundred pounds. But aside from preponderat- ing size and weight they are readily separable from all other birds by the possession of a number of marked characters, the most important of which is the fact that they alone have but two toes — the third and fourth. They have a short, broad, and somewhat flattened bill opening to under the eyes, with the tip strong, rounded, and overtopping the lower mandible, while the oval nostrils are placed in a membranous groove near the middle. The whole head is relatively very small and the neck relatively very long, while the wings are short, imperfectly developed, and provided with long, soft plumes, and the tail is also short and com- posed of curved, drooping plumes; all feathers are without an aftershaft. The legs are very strong and covered in front near the toes with transverse scales. The toes are short but very thick and strong, and provided with short, stunted nails, though that of the outer toe is commonly absent. Another character of importance is that in the adult the head, neck, and legs are destitute of feathers. Species. — The question as to whether the Ostriches shall be regarded as constituting a single species, or some three or four, is apparently still somewhat an open one, some ornithologists recognizing but one, which, however, is divided into several geographic races, while others would consider the differences suffi- cient to rank them as separate species. Be this as it may, the differences are but slight and the habits of the birds practically the same. Thus the Ostrich (Struthio camelus), found in the Soudan, Arabia, and southern Palestine, has the naked skin of the neck, head, and legs bright flesh-colored, and the eggs pro- duced by this bird are smooth. In the birds inhabiting Somaliland (S. molyb- dophanes], the skin of the naked portions is bluish gray in color, while the Ostrich of South Africa (S. australis] has this skin lead-gray or even white-gray. In both of these last-mentioned forms the egg-shells are provided with large, deep pits of a dark purplish color. More recently the form inhabiting Masailand (S. massaicus] has been separated. As might be presumed from their arge size and imposing presence, the Ostrich, or Camel-bird, as it was often called, has attracted attention and interest from very ancient times, a fact attested not only by monuments and inscriptions, but by the abundant mention in the works of Aristotle, Pliny, Xenophon, and 61 62 The Ostriches others, as well as in the Bible. It would perhaps be of interest, did space permit, to quote from some of these ancient sources, but we may only mention that FIG. 23. — North African Ostrich, Struthio camelus. Pliny, following Aristotle, fell into the error of supposing that the Ostrich was part bird and part quadruped. He says: " This bird exceeds in height a man sitting on horseback, and can surpass him in swiftness, as wings have been given Distribution and Habits 6-2 it to aid it in running; in other respects Ostriches cannot be considered as birds, and do not raise themselves from the ground. They have cloven talons, very similar to the hoof of the stag; with these they fight, and they also employ them for seizing stones for the purpose of throwing at those who pursue them." Distribution. — At the present time the Ostrich appears to be confined to certain of the desert portions of Africa as well as similar areas in Arabia and southern Palestine, but there is abundant evidence to show that within historic times it enjoyed a far more extensive range which included portions of Syria, Mesopotamia, eastern Persia, and perhaps Baluchistan, and in recent geologic time (Pliocene) it enjoyed a still wider distribution, since fossil remains of Ostriches, or at least of certain large two-toed birds very near of kin to them, or their eggs, have been found in the Sivalik Hills in India, the Province of Cherson in southeastern Russia, northern China, the island of Samos, etc. The presence of a large Ostrich-like bird in western North America has also been reported by Cope, but this determination rests on a single fragmentary bone, and is thought by later paleontologists to be open to grave question. There can be no doubt, however, that the range of the Ostrich has been undergoing a contraction for a very long period of time, and unfortunately this process seems to be going on at the present day, for countries where it was once reasonably abundant now know it no more or but rarely. The main stronghold is of course the Dark Continent, and there it will undoubtedly linger for a long time, but as this vast area comes gradually under the dominion of at least semi-civilization, the Ostrich must of necessity give way. However, there is probably no danger of its disappearing utterly, at least so long as the votaries of fashion call for its plumes, for, as will be recounted later, it is now extensively "farmed." Habits. — It is of course well known that the Ostrich is mainly an inhabitant of the desert, preferring the dry, sandy wastes, but not altogether shunning the valleys and plains that are studded with scattered low bushes, its commanding stature and long neck permitting it uninterrupted vision in all directions. It is an extremely wary bird, distrustful of all suspicious objects and especially of the presence of man, though it may often be seen in close proximity to herds of zebras, quaggas, giraffes, antelopes, and other quadrupeds. It is a very nervous, restless bird, continually on the move, especially during the daytime, and fleeing at the slightest approach of danger, its proverbial foolishness in hiding its head in the sand and thereby supposing that it was effectually con- cealed being now relegated to the limbo of myths along with dozens of others that have been illumined by the cold facts of science and truth. The Ostrich is gregarious, going about in small parties of from three or four up to a dozen or twenty, and exceptionally as many as fifty have been noted in company. Dur- ing the breeding season the male is polygamous, consorting with some three, four, or five females which are acquired by blandishment or by fierce battles with rivals. The nest is very simple, being merely a slight hollow scratched in the sand, and all the females of a party lay in the same nest. There appears to be some uncertainty as to the usual number of eggs laid, but as many as thirty have not infrequently been recorded, and ordinarily there are a number scattered 64 The Ostriches about the vicinity of the nest which are not incubated, but are said to be used as food for the young chicks. The male performs almost the entire duty of incuba- tion, being occasionally relieved by the females for short periods during the day, and occasionally when the sun is very hot the eggs are simply covered with warm sand, though lthis latter is perhaps as much for the purpose of keeping marauders away as for its warmth. The eggs hatch in some six or seven weeks, the chicks running about freely at birth and accompanying their parents, who are very solicitous for their safety, the male often trying to draw away pursuers by counterfeiting lameness or wounds. Thus Mr. Andersson describes graphically a family party that he once saw near Lake Ngami, which consisted of a male, female, and about twenty chicks the size of common barn-yard fowls. Finding it impossible to escape, the male "at once slackened his pace and diverged some- what from his course; he again increased his speed, and with wings drooping so as to almost touch the ground, he hovered round us, now in wide circles and then decreasing the circumference till he came almost within pistol-shot, when he abruptly threw himself on the ground and struggled desperately to regain his legs, like a bird that had been badly wounded; having previously fired at him, I really thought he was disabled, and made quickly towards him; but this was only a ruse on his part, for on my nearer approach he slowly rose and began to run in an opposite direction from that of the female, who, by this time was con- siderably ahead with her charge." The young Ostriches are said to be remark- ably silent, but the old birds and especially the males have a hoarse, mournful cry, which is likened by some to the roar of the lion, and by others to the lowing of an ox. The omnivorous diet of the Ostrich is proverbial, though in a state of nature they are perhaps not more diversified in their choice of food than many other birds. They feed on herbage, seeds, fruits, berries, etc., varied with occasional insects, small mammals, birds, lizards, and snakes, but in captivity they will eat almost anything that can be swallowed, not infrequently taking substances that may cause their death. While they are capable of existing for long periods without water, they drink regularly whenever opportunity offers, and by some observers they are said to be fond of bathing, especially in very hot weather, when they may wade into a lake or even into the sea until only the head protrudes. They are very fond of salt, a certain amount of which seems to be essential to them. The fleetness of the Ostrich is also proverbial, it being perhaps the most rapid terrestrial animal in the world. A single stride is said to approximate twenty-five feet or more, and it often attains when it first sets out a speed of sixty miles an hour, and can thus easily outrun the swiftest of its four-footed companions ; indeed nothing would be able to overtake it were it not for its silly habit of run- ning in a circle. The latter peculiarity is often taken advantage of to effect their capture, the hunter on a swift horse simply riding the arc of the circle and thus approaching them. Other methods of capture consist of following them with fresh relays of horses or camels until they fall exhausted, in drawing a continu- ally narrowing cordon about them, or in urging them into skilfully concealed Ostrich Farming 65 pitfalls, while the Bushmen, "concealed in the sand or disguised in skins, shoot them with poisoned arrows." Ostrich Farming. — As a matter of fact, probably few if any wild Ostriches are now killed for their feathers since it has been discovered that they can be domesticated and a superior quality of plumes produced. The first attempts at domesticating the Ostrich were made in South Africa about 1864, but these were not entirely successful until several years later, or about 1867. Within less than twenty years the industry had grown to such proportions that $40,000,000 of capital was employed, and the annual income exceeded $5,000,000. In 1891 a rather careful census showed the presence in South Africa of 154,880 tame birds, which number had risen in 1904 to 357,970. In the early days large fortunes were made in the industry when feathers were worth $500 per pound and the plumes of a single bird sometimes brought $100, though the present average annual income in Africa is only about $18 per bird. Ostrich farming was first inaugurated in the United States in 1882, when twenty-two birds were success- fully imported from Cape Town to New York and shipped overland to Cali- fornia. During the next four years other parties ventured in the field of Ostrich farming, and from an importation of forty-four birds, made about 1890, fully eighty per cent of the approximately three thousand Ostriches in America have descended, the last importation — that of twelve Nubians — having been made in 1901. TJie industry is now successfully prosecuted in California, Arizona, Arkansas, North Carolina, and Florida, with the prospect of its enormous ex- tension in the near future. The following account of the industry is taken from Butcher: "A breeding pair of Ostriches will produce from ten to twenty chicks a year, which are worth, when six months old, $100 each; at one year, $150; at two years, $200; at three years, $300 to $350. They commence to breed when four years old, when, if prolific, they are valued at from $700 to $1000 per pair. Exceptionally fine birds sometimes bring as much as $1000 each. Good birds will produce from $35 to $50 worth of feathers each year, and exceptional ones from $75 to $90 annually. Plucking is done by putting the Ostrich in a V-shaped corral just large enough to admit its body, with room for the work- men. A hood, shaped like a stocking, is placed over the head of the Ostrich, when it becomes perfectly docile. The workman then raises the wings and clips the feathers that are fully ripe. Great care is exercised at this time, as a premature cutting of the feathers deteriorates the succeeding feather growth. There is no possibility of inflicting pain in plucking an Ostrich; not a drop of blood is drawn, nor a nerve touched. The large feathers are cut off, and in two months' time, when the quill is dried up, it is pulled out. By taking the feath- ers in this way it causes the bird absolutely no pain at all. An Ostrich is first plucked when it is nine months old, the third plucking being the full crop, which will weigh about one pound. Ostriches mate at four years of age and remain paired for life. The nest, which is simply a hole in the ground scooped out by the breast-bone of the bird, is about one foot deep by three and four feet in diameter. Eggs are laid every other day until about twelve or fourteen are deposited, each of which weighs from three to four pounds. The eggs are 66 The Ostriches turned daily in the nest by the birds, and are incubated forty-two days, the male taking the nest at five in the afternoon, where he remains on duty until nine the following morning, when the female goes on duty. The chicks, when hatched, are about the size of a domestic hen and present a mottled appearance. They grow about one foot in height every month, until they attain full growth, about seven to eight feet, when they will weigh from three to four hundred pounds. When fourteen months old the plumage generally changes, the female taking on a dull gray and the male a glossy black, both growing long white wing-feathers." CHAPTER IX THE RHEAS (Order Rhei/orrnes} N the New World the place of the Ostriches is taken by a somewhat closely related group of birds known as the Rheas, Nandus, or American Ostriches (Rhea). They are confined exclusively to the pampas of South America and are readily distinguished from the true Ostriches by the presence of three toes, a feathered neck, and practically no tail, though they agree with the Ostriches in the absence of aftershafts to the feathers. While there are numerous other differences in the skeleton and soft parts, it may be stated that the Rheas have the powerful legs and hence the similar tremendous speed of the Ostriches. Their habits, as will be recounted later, are also similar. The Rheas are divided into three quite well-marked species, the largest being the Common Rhea (Rhea americana) found in Bolivia, Paraguay, Uruguay, and the Argentine Republic. It is much inferior in size to the true Ostrich, although about fifty-two inches in total length. The general color above is slaty gray, with the head blackish and the neck whitish, becoming dark between the shoul- ders. The under parts are whitish with the exception of two black crescents on the upper breast. This Rhea was once abundant throughout the Argen- tine Republic, but with the advent of firearms it has disappeared from many localities. The following account is from the pen of Mr. W. H. Hudson, who had opportunity for many years of studying its habits: "The Rhea is par- ticularly well adapted in its size, color, faculties, and habits, to the condition of the level woodless country it inhabits ; its lofty stature, which greatly exceeded that of many of its enemies, before the appearance of the European mounted hunter, enables it to see far; its dim gray plumage, the color of the haze, made it almost invisible to the eye at a distance, the long neck being so slender and the bulky body so nearly on a level with the tall grasses ; while its speed exceeded that of all other animals inhabiting the same country. " The Rhea lives in bands of from 3 or 4 to 20 or 30 individuals. When they are not persecuted they show no fear of man, and come about the houses, and are as familiar and tame as domestic animals; sometimes, indeed, they become too familiar. When persecuted Rheas soon acquire a wary habit, and escape by running almost before the enemy has caught sight of them, or else crouch down to conceal themselves in the long grass. Their speed and endurance are so great that, with a fair start, it is almost impossible for the hunter to overtake them, 67 68 The Rheas however well mounted. When running the wings hang down like those of a wounded bird, or one wing is raised and held up like a great sail, for what reason it is impossible to say." FIG. 24. — Common Rhea, Rhea americana. The nesting season in the Argentine Republic begins in July, and several females lay in the same nest, which is simply a depression in the ground, each hen laying a dozen or more eggs. Hudson says: "It is common to find from 30 to 60 eggs in a nest, but sometimes a larger number, and I have heard of a nest Darwin's Rhea 69 being found containing 120 eggs." The incubation is conducted entirely by the male, who watches over the young with great solicitude. The eggs when fresh are a fine golden yellow, but they grow paler day by day, until finally they fade to a parchment white. Eggs are frequently laid away from the nest, scattered on the pampas, for after the male begins sitting on the eggs he drives the hens away furiously, forcing them to deposit the eggs at random. The Long-billed Rhea (R. macrorhyncha), a bird similar in size and habits to the one just described, is found only in northeastern Brazil. It is browner in color and has the crown darker and the bill longer. It must be quite rare. The smallest of the Rheas is known as Darwin's Rhea (R. darwini), the first specimen having been obtained by him while on the celebrated voyage of the Beagle. It is only thirty-six inches in length and is found in Patagonia, mainly south of the Rio Negro. "When pursued it frequently attempts to elude the sight by suddenly squatting down among the bushes, which have a gray foliage, to which the color of its plumage closely assimilates." It has much the same habit of holding up the wings when running as the Common Rhea, but usually it runs with its neck stretched forward, thus making it appear even lower than it really is. The nests are similar to those of the other species, each often containing 50 or more eggs. The eggs when first laid are a deep, rich green ; this fades to a yellowish, then a stone blue, and finally almost white. Many waste eggs are found at a distance from the nest. Darwin's Rhea was formerly very abundant, but the fluffy wing-feathers were exported in large quantities to be used in the manufacture of feather dusters, and as a result the birds have become extremely scarce except in the far interior. They were captured, as are the other species at the present time, by means of the bolos, the well-known South American sling. The one used for Rheas con- sists of two half-pound leaden balls connected by eight feet of twisted rawhide twine. When thrown with proper precision it entangles the legs of the birds, and they become an easy prey. The birds are approached on a fleet horse until within proper throwing distance, or sometimes a whole community of natives unite in enclosing a large area of country, driving the birds towards a constantly decreasing circle, when they are all captured. In recent years firearms have been resorted to, and it would seem that these splendid birds are likely to be wholly exterminated unless steps are taken to protect them. CHAPTER X THE EMEUS AND CASSOWARIES (Order Casuariiformes) HILE it is perhaps hardly correct to assert that the Emeus and Cassowaries, which comprise the present order, are actually the most primitive of the Ratites, it is beyond question that they must have arisen from the original procarinate stem at a point very near those which gave rise to the Ostriches and Rheas. In any event they now differ from them in a number of important particulars, such as the absence of the ambiens muscle and the possession of a distinct aftershaft to the feathers; in fact, the latter is so enormously developed as to be of practically the same length and size as the main shaft. Another of the important differences is the extreme reduction of the wing in the members of the present group, for, as Dr. Stejneger says, it "could hardly become smaller without disappearing altogether externally." There is but a single claw-bearing finger instead of three such as in the Ostrich, while the absence of the ornamental wing-plumes — and for that matter, of tail- plumes as well — serves to further distinguish them. They have very strong legs and feet with three toes, the hallux or hind toe being absent, while the three front toes are provided with claws and have the middle phalanges some- what shortened. The plumage is quite hair-like in appearance and somewhat harsh to the touch. The Casuariiformes embrace two families, the Dromaida, or Emeus, and the Casuariida, or Cassowaries, each with a single living genus.1 The Emeus are distinguished by their larger size, a feathered neck and head, by a broad bill, and the absence of a casque or helmet on the head. The bill has the culmen at the base elevated and sloping to the tip, which overlaps that of thejower mandible ; the oblong-oval nostrils are placed in a large membranous groove. The wings are entirely without remiges and the tail is not apparent, while the toes are un- equal, the inner one being the shorter, and provided with strong, obtuse claws. The second family (Casuariidtz) is distinguished by the smaller size, a long compressed and keeled bill, with the suboval nostrils in the middle of a broad membranous groove, while the head is ornamented by an elaborate bony helmet. The head and neck are destitute of feathers, the skin being brightly colored in life and the neck wattled. The wing bears about five long, stiff, rounded, webless quills, and the inner of the rather long toes is provided with a very long, powerful claw, the claws of the other toes being of moderate size, curved and obtuse. 1 A number of fossil Emeu-like birds have sometimes been set aside as a distinct family — the Dromornithidas, — but their consideration is omitted here. 70 Species of Emeus 71 THE EMEUS (Family Dromeeida) With the exception of the Ostriches, the Emeus are the largest of existing birds, a fully matured individual of the largest species attaining a maximum length of about eighty inches, and standing considerably over five feet high. They are exclusively confined to the deserts and plains of Australia, where they fill the place occupied in similar districts by the Ostriches of Africa and the Rheas of South America. They constitute as conspicuous and characteristic a feature of the Australian landscape as do certain of the larger kangaroos, and like them were being pushed back by the encroachment of civilization until actually threatened with extermination, though recent legislative enactment has done much to protect them. "The King of the Australian fauna" the bird has been called, and, adds Mr. Campbell, "whether seen in private reserves, parks, or in the open, the Emeu always attracts attention. Even the Bushman, who has seen hundreds of Emeus in the wilds, will always glance at the bird or remain to admire its handsome eggs." Before recounting the life history of these remarkable birds, a word of descrip- tion may be given of the several forms. As at present accepted the genus Dro- maeus comprises six nominal species, three of which are known from the Pleis- tocene deposits of Queensland and East Australia, and one (D. ater), which was exterminated some seventy-five years ago, while the remaining two are living. Of these, the largest species and the first to be made known, the Emeu par excel- lence (D. nov(E-hollandi(E), is found throughout Australia in general, though most abundantly in the eastern districts. At a little distance its coat has more the appearance of hair than feathers, due to the loose texture, while down the back there is a parting, where the plumage falls gracefully over on either side. The general color is obscure grayish brown, the feathers with black tips. The feathers of the head and hind neck are black, short, hairy, and recurved, and so thinly placed that the purplish blue color of the skin shows through. The female is similar in coloration to the male, being only somewhat lighter; in size she is slightly smaller than the male. The chicks are grayish white with two stripes of black down the back and two others on each side, each subdivided by a narrow middle line of white. The other living species is the Spotted Emeu (D. irroratus) of western Australia, which is easily distinguished from the other by its spotted plumage, the feathers being barred alternately with silky white and dark gray throughout their length, terminating in a black tip margined posteriorly with rufous. It is also much more slender in habit, the tarsi being longer and thinner, and the toes longer and more slender. The remaining species (D. ater}, now extinct, was very much smaller, attaining a length of only about fifty-five inches, and was darker in coloration. It was apparently confined to Kangaroo Island, South Australia, where it was discovered in 1803 by the French expedition under Baudin. The naturalist of the expedition, Peron, captured three of these Emeus alive and took them to Paris. "A pair was sent to the residence of the Empress Josephine, and the remaining one to the Jardin des Plantes. In 1822 two of the The Emeus and Cassowaries Habits of Emeus 73 birds died. One was stuffed and the other mounted as a skeleton," and until a few years ago this was supposed to represent all that was known of the species. In 1901 a skeleton, believed to be that of the other bird brought back by Peron, was found in the Zoological Museum of Florence, thus closing the melancholy history. Habits. — As the habits of the two living species are similar, the following account is mainly that of the principal species (D. nov