Sy oe lesbo jean Pont ive Se Dao est eee : = Sa a Se = oo ee *} i at. Ses i Pilate Hite ety : Property: of | Whitney Studio Club LABORATORY OF ORNITHOLOGY LIBRARY @&sS ry “ZY C.e4 o¥ V; rq nid. S holt2 CORNELL UNIVERSITY LIBRARY Cornell University The original of this book is in the Cornell University Library. There are no known copyright restrictions in the United States on the use of the text. http://www.archive.org/details/cu31924022546406 LABORATORY OF ORNITHOLOGY © CORNELL UNIVERSITY ~~; ITHACA, NEW YORK - CONCEALING-COLORATION IN THE ANIMAL KINGDOM pay Gy/ “ Varguuce Ce lee ao Jileg 1/96 /° EXPLANATION OF PLATE I i yo, PEACOCK IN THE WOODS. Painted by Abbott H. Thayer, assisted by Richard S. Meryman The Peacock’s splendor i is the effect of a marvellous combination of ‘obliterative’ designs, in forest-colors and patterns. From the golden-green of the forest’s sunlight, through all its © ; tints of violet-glossed leaves in shadow, and its coppery glimpses of sunlit bark or earth, all imaginable forest-tones are to be found in this bird’s costume; and Shey ‘melt’ him into the scene to, a degree past all human analysis. Up in the trees, seen from below, his neck is at its pine” ‘and ‘when sunlit, perfectly represents blue sky geen through the leaves. Looked. down on, in the bottom shades ‘of the jungle, it has rich green sheens which ‘melt’ it into the surrounding foliage. His back, in all lights, represents golden- green foliage, and his wings picture tree-bark, rock, ‘éte., in sunlight and in shadow. His green-blue head is equipped with a crest which greatly helps it against revealing its contour when it moves. Accompanying its every motion, this crest is, as it were, a bit of background moving with it. The bare, white cheek-patch, on the’ other hand, ‘cuts a hole,’ like a lighted foliage-vista, in the bird’s face. The tail, when ce -spread—or even when shut—‘thingles’ in a thousand ways with its jungle surroundings. The ocelli, guaranteed by their forest-scenery colors to: vanish into the background at a short distance, have one peculiarly fantastic use. Smallest and dimmest near the body, and growing bigger and brighter in even progression toward the circumference of the tail, they. inevitably ' lead the eye away from the bird,’ till it finds itself straying amid the foley beyond the tail’s evanescent border. The apread tail looks also very much like .asbrub bearing some kind of fruit or flower. Its coppery ground-color (in a front view) represents ‘perfectly that of the bare. ground and tree-trunks seen between ‘the leaves. The very positiveness of the design in such details as an ocellus, works to conceal the wearer, on the principle explained | in the Introduction by the quotation from Stevenson. The forest i is so full of highly : individualized vegetable forms, and of many-colored spots and streaks made by ‘their. confused outlines, that the predator’s eye, watching mainly for motion, doubtless gives. but slight attention to any of them, or to anything that looks like one of them. In addition to all this, every changed point of view on the beholder’s part makes all the bird’s details assume new colors and new correlations to each other and to the scene.—A. H. T. iy CONCEALING-COLORATION IN THE ANIMAL KINGDOM An Exposition of the Laws of Disguise Through Color and Pattern: Being a Summary of ABBOTT H. THAYER’S DISCOVERIES By ~ GERALD H. THAYER WITH AN INTRODUCTORY ESSAY BY A. H. THAYER ILLUSTRATED BY ABBOTT H. THAYER GERALD H. THAYER RICHARD S. MERYMAN AND OTHERS AND WITH PHOTOGRAPHS NEW YORK THE MACMILLAN CO. 1909 LABORATORY OF ORNITHOLOGY CORNELL UNIVERSITY ITHACA, NEW YORK - ae arr sone te RE SISCOG CopyRIGHT, 1909, BY GERALD H. THAYER ALL RIGHTS RESERVED THE TROW PRESS, NEW YORK LITHOGRAPHS AND HALF-TONES BY A. HOEN & CO., BALTIMORE PREFACE HE first publication of Abbott H. Thayer’s discovery of ‘‘The law which underlies Protective Coloration” was in the American journal of ornithology, The Auk, in April, 1896. This was followed in the next issue of the same magazine by a supplementary article, “Further remarks on the law which underlies Protective Coloration.” The two essays were illustrated by diagrams, and photographs, chiefly of dead birds. They were republished together by the Smithsonian Institution in its “Yearbook” for 1898. A condensed revision of their text, with an introduction by Prof. Edward B. Poulton, was published in the English magazine, Nature, in 1902. Mr. Thayer has also given practical demonstrations of his discovery before various congresses of naturalists, both in the United States and in Europe, and has placed models illustrating it in several European museums (Oxford, Cambridge, and South Kensington, England, and Florence, Italy). Thus this newly discovered basal principle of Protective Coloration has been brought to the attention of most of the world’s best naturalists, and the bare rudiments of the matter have become to some extent current knowledge among them,— though comparatively few of them have yet given proof that they perceive how completely this and certain parallel subsequent disclosures have revo- lutionized the study of Protective Coloration, and supplanted former theories. In the last few years, however, this discovery has been rapidly gaining recog- nition, and mention has been made of it in many writings on Natural His- tory, both popular and scientific, especially in England. Yet the subject is still very far from receiving its destined full and universal appreciation by nature students in general, and much of the current writing about the colors of animals is worse than useless, inasmuch as it works for the retention of antiquated delusions. Indeed, although the study of Protective Coloration vii is now generally acknowledged to be one of the most important branches of zoological science, there still exists among the otherwise well informed a complete ignorance and misconception of the main laws on which Pro- tective Coloration is based. The present book has been constructed for two main purposes: First, to lay before the comparatively few naturalists and others who have duly appre- ciated the original articles on the subject, the results of my father’s further researches, with examples of the working of the newly revealed laws in many branches of the animal kingdom; and second, to present the matter, both in its simplest terms and variously elaborated, to a wider circle of readers. We hope thus to clear the way to a more general understanding and more intelli- gent study of the relations between animals’ costumes and their environments. As the book stands, although it has a far wider scope than the previously published articles, it must be considered merely a fragmentary introduction to the huge and fascinating subject of Protective Coloration. Fundamental principles are defined, and many examples are given, both by illustrations and in the text, of the workings of these principles on actual animals; but nothing like an exhaustive examination of the species of any branch of zoélogy has been attempted. For the most part, we do not draw hypothetical conclusions from facts; but we reveal certain beautiful facts hitherto unknown; we disclose and ex- plain the remarkable power of several naturally applied laws of optical illu- sion—as these applications stand, by whatever causes produced, and as all may see them. That is, we show and analyze the concealing-power of the colors of animals as they exist to-day. The illustrations are of particular importance, inasmuch as they include what we believe to be the first scientific paintings ever published of animals lighted as they actually are in Nature. This will be explained in detail later on. The colored pictures have been painted either from mounted specimens, as in the cases of the Grouse, the Wood Duck, and the Peacocks, or from live captives, as in the cases of the Snake and all the Caterpillars. The pic- viii ture of the Grouse is a faithful copy of a specimen in a house-lighting arti- ficially arranged to correspond to that which the live bird in the forest would normally have; while the background was painted from photographs and outdoor color sketches. The Snake is the joint production of A. H. Thayer, Rockwell Kent, and G. H. Thayer. Three of the caterpillar pictures are contributed by Louis A. Fuertes. The Bird of Paradise sketch is largely the work of Mrs. A. H. Thayer; likewise most of the background in the rab- bit picture, the diagrams of ‘ruptive’ coloration, and two or three black-and- white diagrammatic drawings; besides a good deal of contributive work here and there on other paintings; and an immense amount of miscellaneous labor, invaluable advice and criticism, at almost every point. The various photographs of live birds and mammals which appear in the book have been gleaned from periodicals, or secured by special advertising. We are particularly indebted for valuable pictures to the late Mr. Evan Lewis, of Idaho Springs, Colo.; to Mr. Edward R. Warren, of Colorado Springs; to Prof. F. A. Herrick, to Dr. T. S. Roberts, to Mr. George C. Embody, to Prof. F. A. Lucas, and to Mr. C. Wm. Beebe; also to Mr. R. L. Ditmars, Curator of Reptiles at the Bronx Zodlogical Park, New York, for the loan of a live Copper- head snake, and other favors. ix TABLE OF CONTENTS Intropuction: sy Assotr H. Taaver. An Essay on the Psychological and other basic Principles of the Subject - - - - «© - © «© «© © © 2 6 CHAPTER I Outline of the book’s scope. ‘The Law which underlies Protective Coloration” introduced andanalyzed. Poulton cited . . .« ~~ - -© «© © © © «© © | CHAPTER II Definition of terms. Obliterative Shading, pureandsimple - . . . . «. - CHAPTER III First principles of the use of markings with obliterative shading. ‘Picture-patterns’ . . . CHAPTER IV Picture-patterns, with obliterative shading, on birds. American Woodcock, and Snipe . CHAPTER V Picture-patterns on obliteratively-shaded birds, continued. Terrestrial Goatsuckers (Whip-poor- willsete) 3 ws «S & 8 & @ = mo ce ko & S w « «& ~ CHAPTER VI Picture-patterns on counter-shaded birds, continued. Forest Grouse, Owls, European Wood- COCK Yop oth. la? co CAE Beladeds, Sel Jot) GP ce tee Se ee Ee ee CHAPTER VII Picture-patterns on counter-shaded birds, continued. Grass-patterns, heather-patterns. Spar- rows, Waders, Ptarmigan, et. . - . . . . . . «2. 2... CHAPTER VIII Picture-patterns on counter-shaded birds, continued. Scansorial (Climbing) birds. Creepers, Wrynecks, Woodpeckers, etc. 9. 7 ee ee xl PAGE 13 24 39 33 35 38 49 CHAPTER IX Picture-patterns on counter-shaded birds, continued. Shore-birds—Sandpipers, Plovers, etc. Beech-sand-, pebble- and grass-picturing patterns. Generalizations and comparisons . CHAPTER X Picture-patterns on counter-shaded birds, continued. Reed-patterns, etc., of Bitterns. Other Herons: water-colors and patterns . - . . . . . . 2. 2. «© CHAPTER XI Background-picturing on counter-shaded birds, continued. Marsh-birds: Water-birds (Galli- nules, Rails, Ducks, etc.): detailed analysis of the Wood Duck’s consummate picture- patterns: 2, Se ce Se! Ge ee RRO. Uc ee Se CHAPTER XII Background-picturing on counter-shaded birds, continued. Birds of the ocean. Sky- and water-matching costumes. Gulls, Terns, Gannets, etc. re CHAPTER XIII Birds, etc. The inherent ‘obliterative’ power of markings. ‘Ruptive’ and ‘secant’ patterns, ets ck | Bs ee et, Bg GO Rs a CHAPTER XIV Birds, etc. Special functions of markings. Circle-banded flight-feathers of Hawks and Owls. Eye-masking patterns: eye-blazoning (?) patterns. The coloration of nestling birds - CHAPTER XV Birds. Masking of bill and feet for offensive purposes. The “pantaloons” of Hawks and Owls. Gaudy bills and feet of Water-birds: red and yellow on many water-animals: Belt cited. Jacanas, Anhingas, Herons, etc. Po ee CHAFTER XVI Birds, etc. The manifold obliterative power of iridescence. Changeable colors in general: their part in water-picturing costumes, etc.; (Peacock), Jacamar, the “speculum” of Ducks, ‘jewel-spots,” etc. 2. eee ee CHAPTER XVII Birds, etc. Appendages, and their part in ‘obliteration’: Resplendent Trogon: Pheasants and their long, transversely-banded tails: consummate obliterative equipment of the Birds-of- Paradise: ose Ge eG em CHAPTER XVIIT Birds: miscellany. ‘‘Mimicry” (vs. ‘obliteration’). The gorgeous head-gear of Humming- birds not mimetic; its obliterative functions, etc. Sexual differences of costume a) J xii PAGE 52 56 59 72 77 80 84 87 95 100 CHAPTER XIX Birds, concluded. The birds of tropical forests: brown ground-birds: gaudy perchers on tree-tops: tree-top skulkers, etc.: Parrots and parrot-tails: Toucans: ruptive patterns, iridescence, appendages: extreme color-contrasts: juxtaposition of complementary colors: green light: Trogons and Tanagers: Chapman cited; etc. Winter birds of the snowy North: Blue Jays, Magpies, Goshawks, Titmice, Woodpeckers, cone-birds, etc. White in birds’ costumes. Generalizations and comparisons 2 oe. Be a) Ge a Pet a CHAPTER XX Mammals. A running survey of the coloration of mammals, from bats to whales. Full oblitera- tive shading almost universal among them. Exceptions considered . . CHAPTER XXI Mammals, continued. The markings of counter-shaded mammals: the main types of their obliterative picture-patterns. Leopards, Giraffes, Zebras, Tigers, Antelopes; Hares, Ground Squirrels, etc, etc... ee ee CHAPTER XXII Mammals, concluded, etc. Patterns of mammals that are not counter-shaded. Sky-matching patterns of mammals. ‘Sky-pictures’ on the backs and fronts of Skunks, Zorils, Teledus, Ratels, Ant-eaters, etc. White snow-animals: black markings on white: Ptarmigans, Weasels, etc. Sky-matching white rumps and tails of many fleet ruminants and rodents (Deer, Antelopes, Hares, etc.). Flamingoes, Spoonbills, etc., and morning and evening skies. Other examples of sky-picturing on birds, compared with mammalian sky-picturing. ‘Dazzling-marks,’ fixed and eclipsable; and other special phases of pattern-use. Merriam cited. Generalizations and comparisons . - cs Aig Bs Ba: ae 82 CHAPTER XXIII Fishes. Counter-shading universal among them: exceptions: deep-sea fishes: cave-fishes. The two great divisions of daylight fishes: free-swimmers and the haunters of submerged land. Flat-fishes: Crabs: Rock-fishes. ‘Paradise’ fishes of the tropics. ‘Mimicry” among fishes. “Chameleonism” in fishes. Fresh-water fishes. Trout and “trout-spots.” and Fishes seals. Summary . . oa f SD ca. CHAPTER XXIV Reptiles and Amphibians. Counter-shading universal among them. Tree-snakes and -Lizards. Grass-snakes. Unmarked, striped, and banded snakes. Rattlers, Copperheads, Puff Adders, etc. Markings of lizards, and chameleonism. ‘“Mimicry” (?) among snakes and lizards. Crocodilians. Tortoises and Turtles. Frogs and Toads. Elaborate obliterative coloration—counter-shading and picture-patterns—of certain frogs, toads, and tree-toads. ‘‘Mimicry” amongthem. Newts,Salamanders,etc.. . . xill PAGE 107 119 132 147 160 172 CHAPTER XXV A PAGE Caterpillars. Manifold variations of form and habit: manifold variety of devices for conceal- ment. Predominance of counter-shading: ‘“‘Mimicry”: ‘Obliteration’ and “Mimicry” com- bined. Inchworms. Luna, Poléphemus, Sphinxes. Leaf-edge caterpillars (on maple, birch, beech, oak, etc.). ‘Mirror-backed’ caterpillar. Plumed dead-leaf caterpillar. Dead-leaf-mimicking sphinx. Pine-tuft sphinx. Lappet caterpillar. Concluding re- Marks. Go .d> ee oe ce Ge we: a gt el SR! Ge Ee Ge ee 8H CHAPTER XXVI A glance at Insects other than Lepidoptera (Grasshoppers, Crickets, Beetles, Bees, Wasps, Flies, Dragon-flies, etc.), and at Spiders. Obliterative shading and picture-patterns on terrestrial locusts, etc. ‘Dazzling’-colors. ‘Obliteration’ and leaf-mimicry among grasshoppers. Ob- scure coloration of crickets. Iridescence, ‘ruptive’ patterns, etc., of beetles. Counter- shading and bark-patterns of cicadas. Plant-lice. Water-insects. Obliterative patterns of wasps and bees: iridescence. Dim colors and obliterative markings of the Diptera (Flies, gnats, etc.). Ants. Beautiful obliterative costumes of the dragon-flies: (counter- shading, vivid colors, iridescence, picture-patterns). ‘Mimetic’ dragon-flies. Larval and pupal insects . - - - - - «. | . eo. 8 a oe 2 ee t98 CHAPTER XXVII Butterflies and Moths. Their costumes all concealing, from the gaudiest to the dullest. Changes - in environments: tropical forests. Earlier estimates of the subject: our limitations. Essay in English Entomological Society’s “Transactions” cited. ‘‘Mimicry, Common Warning Colors, and Sexual Selection.” The comparatively small part played by counter-shading. Immense variety of background-pictures. ‘Sedentary’ and ‘aerial’ butterflies. Kallima imachis. Other types of leaf-mimicry. Heliconius melpomene: its flight-pattern: its re- markable roosting-habits. Dainty leaf- and flower-pictures; Metamorpha, Euchloe. Bark-butterflies: wing-folders; Grapta, Vanessa, Calligo, etc. Ground-butterflies: of the fields: of the forest. Wing-waving. ‘Intermediates.’ Shadow-color: sunlit-foliage color. Papilionide. Sun-flecks: sun-streaks: Heliconius charitonia: shimmering foliage. ‘Rup- tive’ flight-patterns. Hummingbird-Papilios. Heliconius melpomene again. ‘‘Batesian and Miillerian Mimicry groups.” Clear-winged butterflies: Bates quoted. Iridescence: major: minor. Morphos: of the tree-tops: of the forest: ‘dazzling’ effect. Obliterative patterns analysed. ‘Ruptive’ patterns again. Flower-like-ness. The ocellus. Owl (?) butterflies. Major and minor ocelli. Appendages. Enormous size of butterflies’ wings, relative to their weight: comparison with bees and birds. ‘Obliteration’ of butterflies’ bodies. Erratic flight. Moths. Urania: ‘target-marks.’ ‘Flat-folding.’ Bright hind wings and masking fore-wings. Marvelously detailed picture-patterns. Near backgrounds. Flat-folding butterflies. Grass-moths (like ptarmigans and grass-frogs). ‘Obliteration’ and “mimicry.”’ Perpendicularly- and cylindrically-folding moths. Extreme types of bark-picturing, and peculiar habits accompanying some of them. Dead-leaf moths. Duality of moths’ and butterflies’ patterns. Nature’s picture-painting again: con- cluding remarks 2 2) ee eee xiv LIST OF ILLUSTRATIONS COLORED PLATES PLATE I—Peacock amid foliage . . - - - JI.—Male Ruffed Grouse in the forest a, te III.—Two sketches of male Wood Ducks, in the water Se ct IV.—Male Wood Ducks. . . .. - - V.—Colored diagram illustrating the use of ‘ruptive’ coloration : Frontispiece VI.—Blue Jays against snow, and Birds-of-Paradise in the tropical forest . . .« VII.—Cottontail Rabbit among ferns and moss and grasses VIII.—Roseate Spoonbills, and the skies they picture . F IX.—Roseate Spoonbill, Red Flamingoes, and twilight sky —- X.—Flamingoes, at dawn or sunset, and the skies they picture XI.—Copperhead Snake on dead leaves a. XII.—Caterpillars (Luna and green sphinx)... XIII.—Caterpillars (of beech-, birch- and elm-leaf-edges) XIV.—Caterpillars (of beech- and oak-leaf-edges, etc.). . . XV.—Caterpillars. (Mirror-back larva, dead-leaf sphinx, frond-bearing Jarva) . . XVI.—Caterpillar, and spider. (Pine-tuft sphinx, porcelain-white spider) 3. Ses OK BLACK-AND-WHITE FIGURES (Photographs from Nature, etc., and diagrams.) Diagram in the text, 3 figs, Chap.I . . . FIGURE 1.—Models illustrating the use of counter-shading. 2.—Model illustrating the use of counter-shading. 3.—Models illustrating the use of counter-shading. 4.-—Models illustrating the use of counter-shading. 5.—Models illustrating the use of counter-shading. Photograph Photograph Photograph Photograph Photograph 6.—Plymouth Rock hen conspicuous against Plymouth Rock hen skins. XV Photograph . FACING PAGE - 38 - 59 « 90 - 497 - 107 - 19 - 147 - 156 - 156 « 172 - 183 - 188 - 192 + 104 - 196 FACING PAGE - %4 - 24 24 24 24 2 24 - 26 FIGURE 7-—White fowl against white cloth. Photograph. - . . . . 8.—White-tailed Ptarmigan in winter plumage, on snow. Photograph - 9.—White-tailed Ptarmigan in winter plumage, off snow. Photograph . 10.—White-tailed Ptarmigan in winter plumage, on snow, but strongly shadowed. Photograph II.— 12,— pPhotographs of the flat skins of birds and mammals ee Se 13.— 14.— TS. , eee Bird-models illustrating the first principles of pattern-use. Photographs 17.— 18.—Pattern perspective. Diagram ms By o-i: 1g.—Pattern perspective. Diagram. .- . . . 2. «© « . 20.— or. — (Nesting American Woodcock. Photographs ei Ge cer ok 22.—Nesting American Woodcock. Photograph . . . . . . 23.—Dead Woodcock, with the counter-shading painted out. Photograph 24.—Dead Woodcock on its side, back-view and front-view. Photographs 25.—Nesting Wilson’s Snipe. Photograph . . . . . 26.—Jack Snipe feeding. Photograph . . . . . . 27.—Nesting Whip-poor-will. Photograph -. . . .« .« - . 28,—Nesting Whip-poor-will. Photograph . . . . - «. . 29.—Nesting Nighthawk. Photograph - . . - -. | . 30:—Nesting Nighthawk. Photograph - - - - - = - 31.—Ruffed Grouse walking. Photograph - - +. ~ . 32.—Nesting Ruffed Grouse. Photograph ee we Be 33.—Nesting Ruffed Grouse. Photograph -. . ae) eae 34.—Dead Ruffed Grouse on its side, back-view. Photograph . 35.—Dead Ruffed Grouse on its side, front-view. Photograph. - . 36.—Bit of Great Horned Owl’s wing, and bit of pine forest. Photographs 37.—Stuffed Long-eared Owl in pine-woods. Photograph s 38.—Stuffed Long-eared Owl among evergreen twigs. Photograph 39.—White-tailed Ptarmigan in transitional plumage. Photograph 40.—White-tailed Ptarmigan in summer plumage, nesting. Photograph - 41.—White-tailed Ptarmigan in summer plumage, nesting. Photograph . 42.—White-tailed Ptarmigan in summer plumage, with chick, among rocks. xvi Photograph FACING PAGE 26 26 26 26 28 FIGURE 43.—Sage Grouse. Photograph a ae ane 44.—Scotch Grouse (Ptarmigan), nesting. Photograph 45.—Scotch Grouse (Ptarmigan), nesting. Photograph 46.—Young Meadowlarks in the nest. Photograph 47.—Female Eider Duck on her nest. Photograph 48.—Young Short-eared Owls in the nest. Photograph 49.—Yellow Wagtail amid grasses. Photograph .- 50.—Male Bobwhite, nesting. Photograph . 51.—Golden Plover, with chick, in grass. Photograph 52.—Nesting ‘Upland Plover.” Photograph 53.-—Nesting American Bittern. Photograph . 54.—Nesting Virginia Rail. Photograph. . . . 55.—Nesting Wilson’s Tern. Photograph “56.— 57-— 58.—Chestnut-sided Warbler feeding young. Photograph 59.—Chestnut-sided Warbler (and Catbird). Photograph 60.—Blue Jays amid foliage. Photograph . 61.—Chickadee at nest-hole. Photograph 62.—Oyster-catcher on rocks. Photograph 63.—Guillemots on rocks. Photograph .- . . 64.—Stuffed Goshawk against pine-tops. Photograph 65.—Tip of Goshawk’s wing against pine branches. Photograph Photograph 66.—Stuffed Goshawk on its back on the forest floor. 67.—Baby Golden Plover. Photograph . 68.—Ringed Plover, at its nest. Photograph. . 69.—Lapwing on its nest. Photograph . . 70.—Killdeer Plover on its nest. Photograph 71.—Killdeer Plover at its nest. Photograph 72.—Baby Killdeer Plover, crouching. Photograph 73.—Nighthawk chick, on the ground. Photograph 74.—Nighthawk chick, on the ground. Photograph 75.—Baby Common Gulls. Photograph 76.—Baby Curlew. Photograph 5 77.—Baby Crested Grebes. Photograph. . . 78.—Baby Red-breasted Mergansers. Photograph xvii } Aric monochrome butterflies, against light and dark. Photograph FACING FIGURE PAGE 79.—Glinting pool amid grasses. Sketch. . - . -». . « « «© © « «= 82 80.—Baby Horned Grebes on their nest. Photograph. -.- . - . . « - 82 ce dh S238 92.—Cardboard zebra, No. 3. Photograph, retouched. . . . a aie ee Ae ES: 93.-—Chipmunk among dead leaves. Photograph. - . . . . . . . - 138 94.—Mbega Monkey. Photograph - - -~ .~ . .«. . . . « « « . 1346 95.—Common Skunk against sky and bushes. . Photograph (stuffed skin) we - 148 96.—Common Skunk against sky and bushes, side-view. Photograph (stuffed skin) - 148 97.—Common Skunk against sky and bushes, nearer view. Photograph (stuffed skin). . 148 98.—Common Skunk against dark. Photograph (stuffed skin) - . « 148 99.—Prairie Skunk against the sky-line. Photograph from stuffed skin ud. Re 148 100.—Prairie Skunk against dark. Photograph from a stuffed skin sw os wo a48 1o1.—Spilogale against sky-line. Photograph from stuffed skin . 2 150 102.—Spilogale against the ground. Photograph from stuffed skin. E 150 103.—A compound picture, of Skunks and Hares. Photographs (and or : 150 104.—Diagram illustrating the use of ‘dazzling’-marks. Photographic ¢ RE. cs - 152 105.—Diagram illustrating the use of ‘dazzling’-marks. Photographic 3 - 152 106.—Diagram illustrating the use of ‘dazzling’-marks. Photographic . -. -. . . 82 107.—Stuffed Prong-buck, rear-view, against sky. Photograph a ee ee 154 108.-—Stuffed Prong-buck, rear-view, against ground. Photograph . . 5 154 109.—Stuffed Prong-buck, half side-view, silhouetting against sky. Photograph - 154 110.—Prong-buck as in Fig. 109, but photograph shaded to suggest night-effect. PhetieraDs retouched Be Se oe os P 3 - 154 111.—Deer or Antelope aithanateea against ign sky. Sketch e 4 . - 154 112.—Dead Hare, rear-view, against sky. Photograph = OF An UB el OS oa ae gy 113.—Dead Hare against ground. Photograph er ge ve EE ce cep CS) NTEY xvill FIGURE 114.—White card againstsky. Photograph . . . . . 115.—-White card against ground. Photograph 29 oe cha 116.—-Imitation Egret, without plumes. Photograph 117.—Imitation Egret, with plumes, against dark. Photograph 118.—Imitation Egret with plumes, against white. Photograph 119.—Diagram illustrating the effect of certain patterns. Drawing 120.—Fifty little pictures, mainly photographic, of real holes, and of counterfeit holes in animals patterns) om Ge) em wm ae 121.—Green Snake, right-side-up. Photograph - 122.—Green Snake, inverted. Photograph ese 123.—Rattlesnake among stones. Photograph and drawing . 124.—Brown Lizard on apple-tree bark. Photograph . . . oa } Brown Wood Frog among dead leaves. Photographs 126.— 127.—Common Garden Spider on its web. Photograph Se 128.—Orange-tip Butterflies on cow-parsley. Photograph . . 129.—Butterflies on vegetation. Photograph . . 130.—Light butterfly with shadow-colored fore-wing borders. Photograph . 131.—Small Tortoise-shell Butterfly on pebbles. Photograph 7 132.—Ocellus on a butterfly-model. Photograph . os ¢ 133.—Moths, Butterfly, and Pheasant’s tail, on dead leaves, etc. Photograph . 134.—Two Grass-moths, on grass. Photograph . 135.—Tiger-moth on sprig of Box. Photograph ee 136.—Four Bark-moths, on Maple bark. Photograph . . . 137.—T wo Bark-moths on Pitch Pine. Photograph . . . 138.—Three Bark-moths, on Gray Birch. Photograph. . . 139.—Pandorus Sphinx Moth on a White Birch tree. Photograph 140.—Bits of sphinx-moth pattern and of bark-pattern intermingled. xix Photographic : ¥ FACING PAGE 154 154 156 156 156 159 159 174 174 174 180 180 180 216 216 216 216 230 230 235 235 235 235 235 237 237 CONCEALING-COLORATION IN THE ANIMAL KINGDOM INTRODUCTION HILE man has gone on wresting from Nature one deep-buried secret after another, the whole field of protective coloration has lain un- concealed, inviting recognition, resplendent with wonderful and beautiful phenomena. Yet of these he has remained uncognizant, or caught only fragmentary glimpses, piecing together the fragments with the aid of false hypotheses, which have presented such a spectacle of inconsistency as to bring the whole subject into widespread contempt. The entire matter has been in the hands of the wrong custodians. Apper- taining solely to animals, it has naturally been considered part of the zodlo- gists’ province. But it properly belongs to the realm of pictorial art, and can be interpreted only by painters. For it deals wholly in optical illusion, and this is the very gist of a painter’s life. He is born with a sense of it; and, from his cradle to his grave, his eyes, wherever they turn, are unceasingly at work on it,—and his pictures live by it. What wonder, then, if it was for him alone to discover that the very art he practices is at full—beyond the most delicate precision of human powers—on almost all animals? Fortunately, although this search, like all others, requires a specialist, the beautiful things discovered are appreciable by all men; and our book presents, not theories, but revelations, as palpable and indisputable as radium or X-rays. Naturalists have not understood the principles of objects’ distinguishability. Let us first consider the part distinguishability plays in animals’ lives. Sight, in the great majority of cases, is the sense by which at the last moment the quarry’s fate is decided. Had the cougar, wolf, or fox no eyes, he would starve. Had the hare no sight, he could not tell when to abandon his squatting and spring away, or which way to dodge the murderous leap that would follow. Scent brings the predator along the trail or up-wind nearly to the game, but were this pursuer blind, he would seldom (except in 3 holes) * catch anything more active than a tortoise, as everyone knows who has watched a cat, dog, or ferret falteringly nosing out the whereabouts of a bit of flesh, or a setter pointing a bird. The dog commonly points the stream of scent that is passing his nose, without the slightest appearance of knowing where the bird is. In fact, for the purpose of knowing just where their game is, scent offers animals no immediate aid; and the same is true of sound. For scent and sound can go round corners, whereas sight operates solely in a straight line. Sight is also out of all proportion the swiftest; for while scent moves practically only at the air’s rate, and sound only 1,121 feet a second, light, which means sight, travels 182,000 miles a second! This combined straightness and swiftness gives sight, and sight alone, the power to tell the predator exactly where his quarry now is, and the quarry where his enemy is. Thus, at these crucial moments in the lives of animals, when they are on the verge of catching or being caught, sight is commonly the indispensable sense. It is jor these moments that their coloration is. best adapted, and, when looked at jrom the point of view of enemy or prey, as the case may be, proves to be ‘ obliter- ative.’ All experiment corroborates our supposition that human and animal eyes bear essentially similar relations to light vibrations. (And, in fact, almost all theories about the functions of animal’s colors are based on this hypothesis.) All naturalists perceive the wonderful perfection of the twig mimicry by an inchworm, or of bark by a moth, or of a dead leaf by the Kallima butter- fly. It is now apparent that almost equally marvelous concealment-devices, in one shape or another, are general throughout the animal kingdom; the most gorgeous costumes being, in their own way, climaxes of obliterative color- ation scarcely surpassed even by moths or inchworms. This discovery that patterns and utmost contrasts of color (not to speak of appendages) on animals make wholly for their ‘obliteration,’ is a fatal blow to the various theories that these patterns exist mainly as nuptial dress, warning colors, mimicry devices (i. e., mimicry of one species by another), etc., since these are all attempts to explain an entirely false conception that * In the case of the weasel family, this exception is doubtless a large one. 4 such patterns make their wearer conspicuous. So immeasurably great, in the case of most animals, must be the value of inconspicuousness, that such de- vices as achieve this to the utmost imaginable degree, upon almost every liv- ing creature, demand no further reason for being (although doubtless serving countless other minor purposes). The theory of Natural Selection is based on the belief that organisms are susceptible of modification limited only by the duration of the circumstances causing it, or by the attainment of ultimate perfect fitness to environment. Now, since the same circumstances would always be best met by the same characters in an organism, we are not surprised to find all animals, of how- ever widely different orders, resembling each other in shape and color in evi- dent proportion to their degree of having the same habitat and habits. The whole class of mammals, dwelling mainly on the ground, have mainly ground color, and a form varying no more than their situations and habits. The same thing is equally true of thousands of species of birds, of fishes, reptiles and insects; even mammals, if they lead a fish’s life, like the cetaceans, have the general shape and color of fishes. (A parallel case is that of humming- birds and hawk moths.) No fish of the open ocean is permitted by Nature to wear any essential color-distinction from his hundreds of neighbor species. He has, for all we know, the same need of ‘‘ warning colors,” “‘banner marks,”’ etc., as any land animal; but Nature vouchsafes him no pin-point of color be- yond that of the sky-lit deep-sea water. ‘The same is true of the inhabitants of the aérial ocean spaces. Save for a good many small, bright-colored dec- orations, mainly of the beaks, worn by such species as breed where such col- ors abound, Nature allows them no colors which are not those of sea surfaces, clouds and sky, or of somber cliffs; or, for the diving ones, dim water-colors, more like those of the fishes themselves. In short, the so-called “nuptial colors,” etc., are confined to situations where the same colors are to be found in the wearer’s background, either at certain periods of his life, or all the time. Apparently, not one “mimicry” mark, nor one “warning color” or “banner mark,” nor one of Gadow’s light-and-shadow-begotten marks, nor any “‘sex- : ually selected” color, exists anywhere in the world where there is not every reason to believe it the very best conceivable device for the concealment of its wearer, either throughout the main part of this wearer’s life, or under certain peculiarly important circumstances.* These deceptive patterns, painted by Nature on the exteriors of almost all animals, will prove to be an inexhaustible field for studying their psychology. Stevenson makes Alan Breck say ‘“‘Them that cannae tell the truth, should be aye mindful to leave an honest, handy lee behind them. If folk dinnae ken what ye’re doing, Davie, they’re terrible taken up with it; but if they think they ken, they care nae mair for it than what I do for pease porridge.” The psychological principle in this lies deep in Nature’s artifices for concealing animals. Wherever, for instance, the animals are habitually to feed amidst brilliant vegetation, she is apt to give brilliant marks rather than simply equip- ping them to match the soberer interstices amidst the brilliant details. The principle is, evidently, that amidst a large number of similar striking objects, an imitation of these has the support of the credit of all the real ones. ‘There are before the eye so many obviously real ones, that the mind refuses to take the trouble to suspect any. For a red mark on a bird, fish, or butterfly to pass itself off for a red flower among many red flowers is like Alan’s telling the passer-by that his errand is such a familiar one as the search for a runaway horse; while, in such a situation, to try to escape notice by imitating a dusky place, may be as much more risky as for Alan to assert merely that he is not on a mysterious errand.t The so-called “‘nuptial’’ costumes of animals are * Plainly, most details of an animal’s body serve many purposes; and whatever law develops the detail’s main characteristics,.doubtless causes it also to be modified to meet each minor use, in the degree of its relative importance. To illustrate with human experiences, the hunter’s rifle, besides its main use, serves also at times the purpose of a balancing-pole, or even a club; and, carried over his shoulder as he goes away, it serves to show his family that there may be venison for dinner; yet its essential purpose is to Rill that venison,—for this, nothing but a rifle would serve. In the same way animals’ markings doubtless serve in various lesser degrees most of the purposes that have been attributed to them. + Another good analogy is the universal human propensity to trust circumstantial evidence too much; to believe any accused person guilty, because the sin he is accused of is a common one. 6 demonstrably an increase of such potency of obliterative coloration as belongs to all gorgeously varied costumes, and this at the very period when concealment is most needed. It is of great importance to understand that skill and strength are not all confined to predators. It is plain, upon any hypothesis whatever which rec- ognizes the existing fitness of all forms of life to their uses, that this fitness is presumably just as great in the quarry’s case as in the hunter’s. The fleet- ness and alertness of the hare are a good match for the stealth and power of the lynx, etc., and the consequent balance between predator and prey is doubtless known to the instincts of each animal. The lynx’s obliterative col- oration just as much increases his dangerousness to the hare, as that of the hare adds to the lynx’s difficulty in catching him. Although inconspicuousness is merely an approach to indistinguishability (of course this positive term refers only to occasional effects), yet the practical workings of the two are worth considering separately. Indistinguishability enables predators to ambush their prey, and, on the other hand, it protects any quarry to the windward of which the predator may pass (if he is not trail- ing it). Mere inconspicuousness of the predator causes him to be less avoided by the animal he preys on, while for the prey it means a minimizing of the stimulus he gives to his enemy’s rapacity. Also, at the ultimate moment both sides profit by showing as indistinctly as possible, so that the rapacious animal is harder to dodge, and the prey a fainter target to strike at. Sports- men, insect-catchers, and tennis players will understand this. Again, in a very large class of cases the question is not whether the hawk, for instance, can espy, or the fox, scent, his game, but whether there appear to him, at the moment, sufficient advantages on his side to stimulate him to an effort such as has far more often failed than succeeded. Also, a single instant of success- jul disguise suffices to protect an animal from a swiftly passing marauder, a hawk, for instance. In a rapacious animal’s case there must be an eternally shifting balance between greed and imertia. Doubtless a sufficiently strong incentive—a very obvious chance—might rouse even the most gorged of 7 hawks to attempt another capture; while, on the other hand, one that was starving, or whose young were, would achieve marvels of daring and power. Watch an Accipiter sitting amidst the usual abounding bird life of summer woods. You will often look long for any sign that the small birds fear him, or that he threatens them. One evidence that this balance of circumstances is what keeps the two classes of animals so peaceful in their general demeanor toward each other is to be found in the alacrity with which predatory animals rush to investigate an imitation of a bird’s or mouse’s cries of distress. So, too, a pickerel, after long listlessly watching your bait, with the barest signs of interest, will often seize it the moment it gets foul of a lily pad and seems in difficulty. Other things being equal, animals that hunt by sight (i. e., do the whole thing by sight, as hawks do in distinction from most rapacious quadrupeds) would try for the most conspicuous prey, just as a sportsman is almost irresistibly drawn to shoot at the best mark in a flock of birds—so much so, that, if he be a beginner, he may let them all go by, after swinging his gun upon one after another of them, unable to keep to the one first se- lected, when another has become more conspicuous. Just as men who live amidst constant danger have powers of instantane- ous action unknown to farmers and shopkeepers, so the hare and the deer have acquired in their hard school similar alertness and speed. In terms of the theory of natural selection, the quarry has had just as many centuries to learn his part, as the predator to learn his. Evidently, the hawk’s nerves know this so well that, instead of wasting energy, they, so to speak, ‘take into their own hands’ the business of being ever ready to hurl him like lightning on a disabled or preoccupied victim. Since we may assume that there zs this closest balance between the respect- ive powers of predaceous animals and their game, it follows that, in the long run, smallest advantages will tell. And if they do tell, the same process, what- ever it be, that has adjusted moths to bark and made inchworms look exactly like twigs, must be everywhere at work, carrying each advantageous trait to similar perfection. In the days of swordsmanship, there was little difference between fine fencers, yet the best one would, by the most delicate shades of superiority, get his sword through his opponent’s ribs in one fight after another till all men feared him. That such things are more than luck is well known to life- insurance companies and army recruiters. Why do they take no chances, but, instead, calculate averages, and reject each applicant whose defects exceed the limit, even in cases where this applicant has a great many chances of con- tinued health—where he may outlast sounder men? If war departments know that minute defects in individual soldiers will affect even a single cam- paign, how is it conceivable that, in the animal kingdom (if there be natural selection at all, or any corresponding principle), hundreds of thousands of years should leave any sifting unperfected, any slightest adaptation incom- plete? All characters, barely noticeable by us, but which are in the long run of more use than harm, must develop. This book demonstrates that the colors, patterns, and appendages oj ani- mals are the most perfect imaginable effacers wnder the very circumstances wherein such effacement would most serve the wearer. For any particular animal to be seen looking conspicuous means no more than that he is not at those moments looked at under the circumstances for which his concealing-colors are effective; and man’s persistent misconception that bold patterns, etc., make the wearer conspicuous, is based on a psychological principle. Let us imagine one hundred butterflies of the same species within range of a nat- uralist’s sight, and ninety-nine of them concealed from him by the effect of their bold patterns, while the hundredth happens to be noticed by him, and, of course, identified by all its attributes, bold pattern and all. What impres- sion about the species has this naturalist gained through this experience? He carries away simply one more mental picture of a butterfly of this boldly patterned species, and mistakes its specific recognizability for intrinsic con- spicuousness. ‘The ninety-nine successful disguises have made no impression at all. So he goes on, accumulating a conviction that the species is conspic- uous. He can tell you a long list of cases to prove it:—while the actual case 9 is, that for every one he saw there were as a rule scores, within range of his sight, concealed by the very patterns which he believes to make the species conspicuous! I had, lately, a chance to prove all these things upon a natural- ist who believed, as has always been held, that ‘‘conspicuous”’ patterns, etc., make conspicuous objects. Of each species that he declared to be a con- spicuous one I arranged either a stuffed specimen or a good imitation, and placed it full in his sight, out of doors, in the most natural of situations. And each time he was amazed at failing to find it conspicuous. In every case of a series of such tests, he discovered the specimen only after a more or less long search. One case is enough to cite here. He declared a coral snake, with its red, black, and gold rings, to be ‘‘the most conspicuous object in Nature.” I placed on bare ground some imitation snakes—one black, one scarlet, one gold, one earth-color, and one good facsimile of a coral snake, with its bright scarlet, gold, and black rings, and the counter shading universal among snakes, and invited him to look at them from a distance of about twelve yards. He saw at once all but the coral snake, and would never have known the latter was there had he not been told. Yet in this case he had been told just where to look, on a bare open space of flat ground. I asked him if he still believed that a naturalist’s eye takes in most of the coral snakes that come within its range in the complex scenery of the jungle! By such experiments all his beliefs on the subject were one by one confuted,— as, in the end, he most openly and generously acknowledged. Concealing-coloration means coloration that matches the background. But since an object’s background varies with the point of view, there can be no such thing as complete, intrinsic inconspicuousness. ‘The means of ob- jects’ recognizability, no matter how they are colored or marked, is almost always their silhouette—i. e., their outlines in ‘relieving’ darker or lighter or differently colored against their background. If an object moves about— or, what amounts to the same thing, if the beholder moves about—the object is bound to silhouette in various ways against various backgrounds. If the 10 object moves about ouddoors, in sunlight and in shadow, this versatility of silhouetting becomes extreme. Day’s vast chiaroscuro can make the black- est objects ‘relieve’ bright against dark shadows, and the whitest objects ‘relieve’ shadowy dark against the light. Given a sufficient freedom of motion on the part of object or beholder, and, aside from changes in the object’s own illumination, its backgrounds are bound to range through this whole scale of variations and contrasts, from earth and its darkest shadows to sky and its brightest lights. Patterns on animals’ coats are the utmost that Nature can do in opposition to these potent vicissitudes of silhouetting. ‘This is the point at which Darwin, Wallace, and others went wrong; and this in spite of the fact that their supposed ‘‘conspicuous” species are, doubtless, more easily detected, in the long run, than their “cryptic” species. It is true that if one sits still in a wild place one will usually detect more individuals of the so-called conspicuous kinds. But this is because they are mostly ar- boreal or aérial species which a terrestrial observer is apt to see against a much wider gamut of background than that to which the so-called cryptics are sub- jected. ‘They are the ones that have to move about most freely in sunlight and in shade, and against all manner of backgrounds, from shining sky to the darkest forest shadows. Their bold coloring, however, minimizes, not increases, their conspicuousness in this difficult situation, where the more nearly monochrome so-called cryptics, adapted for ‘‘sticking close” to tree trunks or the brown ground, would be comparatively conspicuous. One animal most needs to escape observation from above, another from below, and others equally from all directions. It follows that some must be colored to match brown ground, some to match the sky, or sky and foliage, while some must have costumes combining these extremes; and just such wonder- ful adaptations, in highest development, prove to be universal. Animals, therefore, are conspicuous when seen from any but the right view point—white sky-matchers showing bright against the ground, brown earth-matchers sil- houetting dark against the sky, etc.,—with all the magic of their concealing- costumes lost. Again, it follows that we should be inclined to count con- II spicuous those species which we most commonly see against the wrong back- ground. This is what Darwin and Wallace did,—and, failing to understand the effect both of pattern and of visibility through contrast and silhouette, they made the fundamental mistake of ascribing the conspicuousness to the very thing which opposes it. Their immense prestige has so riveted this error in students’ minds as to have doomed the whole subject, hitherto, to confusion and neglect. Naturalists repeatedly experience the difficulty of detecting brilliantly colored birds and strongly marked quadrupeds—commonly recording each case as surprising or inexplicable under the supposed circumstances, or some- times manifesting a true apprehension of some one particular case, without seeing that they are dealing with a universal principle.* Among the aboriginal human races, the various war-paints, tattooings, head-decorations, and appendages, such as the long, erect mane of eagle feathers worn by North American Indians,—all these, whatever purposes their wearers believe they serve, do tend to ‘obliterate’ them, precisely as similar devices ‘obliterate’ animals. The color-relations of earth, sky, water, and vegetation are practically the same the world over, and one may read on an animal’s coat the main facts of his habits and habitat, without ever seeing him in his home. ApBBott H. THAYER. Monapnock, N. H., December 15, 1907. * Here is a simple way to discover whether one has the full color sense necessary as a basis for studying obliterative coloration. If, like a multitude of people, one cannot see that shadows on an open field of snow, or on a white sheet, under a blue sky, are bright blue like the sky overhead, one will probably prove more or less defective in all color-perceptions. To prove that such shadows are sky colored, lay a colorless mirror on the snow in such a shadow,—its reflected sky will match the surrounding snow. 12 CHAPTER I GENERAL OUTLINE OF THE BOOK’S SCOPE. THE ‘‘LAW WHICH UNDERLIES PROTECTIVE COLORATION”? INTRODUCED “ FYROTECTIVE COLORATION,” with its achievement of the wonder- ful inconspicuousness of many wild animals in their native haunts, has been recognized since the earliest days of Natural History study. But the true character of this phenomenon has been ignored or misinterpreted, and the phenomenon itself has been observed only in one small corner of its wide field of action. It has waited for an artist, in the last years of the nineteenth century, not only to recognize the basic working lcws of protective colora- tion, but to perceive that the many animals of supposed “cor picuous” attire are almost all colored and marked in the way most potent to conceal them. We will begin with an exposition of the long-ignored laws involved in such protective coloration as has been generally noticed, leaving to be developed in later chapters the revelation of its larger scope. Since time immemorial, human hunters must often have been aware of the strange elusiveness of motionless deer in a brown landscape, or of hares or partridges squatting on the ground. ‘Those who stopped to seek the cause of this, perceived that the deer or partridge looked almost exactly like the land- scape or the ground in color, and were satisfied with this explanation; and thus was evolved that stock phrase of nature students, which has found a place in almost all books about animals, that these inconspicuous creatures are “colored like their surroundings.’”’ But it is our first task to. show that this logical-seeming and universally accepted explanation is inadequate and misleading, and to vindicate the paradoxical-sounding statement that if crea- 13 tures were purely and simply “colored like their surroundings” they would not be inconspicuous at all. This has already been explained by articles in several scientific and popular magazines, but the explanation must be repeated here in full for the benefit of those who have not seen the former expositions of the discovery. What people commonly fail to perceive in connection with this matter, is that the exposition is really that of a discovery, i. e., of an indis- putable optical fact, hitherto unnoticed, and not merely that of one more theory. It is the revelation of how animals’ wonderful inconspicuousness in their normal haunts, recognized for centuries but in its essence never under- stood, is really achieved. That is, not a description of any course of evolution or process of pigmentation, but the revelation of the manner in which the existent system of coloration renders animals nearly invisible on their native heath. I will quote, with slight modifications, from the original article published in 1896, and from that published in Nature in 1902. “The newly-discovered law in its application to animals may be stated thus: Animals are painted by Nature darkest on those parts which tend to be most lighted by the sky’s light, and vice versa. The accompanying diagram illustrates this statement. ‘‘Animals are colored by Nature as in A, the sky lights them as in B, and the two effects cancel each other, as in C. The result is that their grada- tion of light-and-shade, by which opaque solid objects manifest themselves to the eye, is effaced at every point, the cancellation being as complete at one 14 point as another, as in C of the diagram, and the spectator seems to see right through the space really occupied by an opaque animal.” In the Nature article this was reworded and emphasized as follows: “If an object be colored so that its tones constitute a gradation of shading and of coloring counter to the gradation of shading and of coloring which light thrown upon it would produce, and having the same rate of gradation; such object will appear perfectly flat;—retaining its length and breadth, but losing all appearance of thickness; and when seen against a background of color and pattern like its own will be essentially indistinguishable at a short distance. All persons who have seen the models which illustrate this, know that they prove it. Now, if this stands proved, the fact that a vast majority of creatures of the whole animal kingdom wear this gradation, developed to an exquisitely mi- nute degree, and are famous for being hard to see in their homes, speaks for itself. It is plain that their color-gradation can no more escape effacing their look of solidity than the law of gravitaticn can escape drawing a pro- jectile to the earth. This is so obvious, that one hears on all sides expressions of wonder that it was so long unnoticed. I may add that all persons of trained sight, such as artists, perceive it everywhere among wild creatures. Other people supplement their undeveloped sight-sense by their other senses, and if they know an animal 7s solid, think he Jooks solid. “Let anyone look at a ball, or egg-shaped object, anywhere out of doors, and when he has recognized its shading, from its light side to its dark, try to so color it, where it stands, as to efface this shading. If he succeed, he will find that Nature has swiftly guided him through the same process which has taken her so long on the coats of animals, and that he has given the object the counter-gradation I speak of; and it will have dawned on him that so long as light makes its one gradation on objects, there is only the one way to neutralize it. In short, I simply prove that this arrangement of animals’ colors is what so marvellously effaces them, and leave it to others to discuss the question whether concealment be a benefit to an animal, and whether the fact that it is a benefit be the cause of his being concealed. All who believe in Natural 15 Selection, however, will of course feel that this color-law is its work; and since it is so almost universally in use, and accounts, apparently, so almost exhaustively, for all the attributes of graded animal coloring, I believe it will ultimately be recognized as the most wonderful form of Darwin’s great law.” The foregoing extracts together fully state the newly-revealed principle, which in its various elaborations is the foremost subject of the present book. But it may be well before going further to dwell at greater length on the sim- plest aspect of this fundamental principle. No one who has studied animals in nature can have failed to notice either their frequent wonderful inconspicuousness, or the fact that ninety-nine per cent of them are dark colored on the back and light colored on the underside. On the other hand, even school children are daily taught that the only way to draw a representation of a ball or cylinder is to shade it from a bright central point or middle line to dark borders—or, if the object is to be shown in side view, under a top light, to shade it from very bright above to deeply dark below. Yet the obvious conclusion that the contrary gradation of shades, as it exists on the rotund bodies of animals, is the cause of their wonder- fully unsubstantial appearance, has never been drawn till now, and even now is but slowly accepted by most people. This is because few people recognize the vast part played in the visible world by light-and-shade. As has already been said, the known fact of solidity suffices, to many minds, without any inquiry into the means by which that solidity is manifest to their sight. Light- and-shade, color, and line, are the three great factors of visibility. Line perspective enables the eye to judge to a large degree of the forms of objects, and the various distances of their different parts, especially in the case of large ones of elaborate shape, such as buildings; but the visibility of line is de- pendent on color, and still more on light-and-shade. I here use ‘line’ to mean the visibility of the boundaries of material surfaces and their parts. It is obvious that this is dependent on color, since if a monochrome flat sur- face is so placed relative to the eye of an observer that one of its boundaries is against another flat surface of precisely the same color, and similarly lighted, 16 that boundary will be invisible; and it is just as evident that it is dependent on light-and-shade, since two objects of like color can be differentiated, and two of different colors can be made to appear to blend together, by effects of shadow and light. Light-and-shade is more important than color, because it is primarily an attribute of form, while color is only secondarily so. The reader should look at his hand, or any other small object of elaborate form, and consider the factors of its appearance which enable his eye to perceive it, in its entirety and its details. The form and position of the various por- tions are revealed by the lines of perspective, and by the light-and-shade, that is, the shadows on those parts which are most averted from the prevailing light, and the points of high-light on the reverse portions. We have already seen that these main factors are interdependent on each other. Color, the third factor, plays a much smaller part. A projecting portion, for instance, may be of a different color from the rest, and will then be distinguishable from it by its color alone, but without the line and light-and-shade it would appear merely as a spot of color on the general surface—the projection would not show as such, except in so far as its peculiar color revealed its character- istic outline,—when, as in the case of the counter-shaded animal, the fact of its solid form would be mentally inferred, rather than actually seen, by the observer. On the other hand, there is the color difference between the sur- faces which more directly catch the bluish sky-light, and the relatively orange- colored shadow-portions, etc., aside from other possible color incidents of reflected light; but these are secondary factors, since if the whole object were of a uniform neutral tint, and the color effects of the light were eliminated, the visibility of its various parts would scarcely be decreased. (Drawings in black and white, and photographs, are excellent exponents of this principle.) In just this way the form-variations of all solid objects are revealed to the eye —according to the simple law, that depressions lose light and are therefore darker, and elevations gain light and are therefore brighter; surfaces averted from the prevailing light being equivalent to depressions, and those turned toward it to elevations. It is, then, primarily by the light-and-shade on solid 17 objects, that the eye is made aware of their existence, their main form, their position, and all their minor modelings. Now, since this is the case, it follows that animals, however colored, would always be more or less conspicuous in their natural environment, and all the details of their form would be dis- tinctly visible, unless their surfaces bore such an arrangement of light and dark shading of the colors as could counteract the shading which the de- scending daylight applies to their solid bodies. This counter gradation of shades, from dark mid-backs to white mid-bellies, is, as we have seen, pre- cisely the system of coloration (‘Mimicry’—vide Chapter II—aside) of almost all protectively colored animals. The ghostly elusiveness of a counter-shaded creature’s appearance is at its best under a diffused sky-light, such as that in the forest, or the open fields on a cloudy day, because no color gradation can adequately cope with the full and concentrated light of the sun itself, which produces sharply contrasted areas of light and shadow, rather than a graduated shading. Even in full sunlight, however, the light from the wide expanse of sky is still the principal factor. To understand this, the reader should compare the difference between a sunlit patch of ground and a neighboring one which is cut off from the direct sunlight, with the difference between the latter and the mouth of a deep hole which is cut off from both sun- and sky-light. The one is the slight difference between a sunny and a shady spot, the other is the vast difference between night and day. A patch of bright sky no bigger than the sun is far less brilliant, but the vast sum of such patches which the entire expanse of sky contains, yield a far greater light than the sun itself. (This is analogous to the principle of sound, which makes the sum of the concurrent echoes of a clap of thunder far louder than the initial sharp electrical report itself.) An animal’s counter shading, then, is effective even on open ground on a sunny day, although the superadded direct sunlight interferes with the perfection of its working. On this basis of the obliteration of the light-and-shade aspects of a solid creature, the most exquisite color resemblances to the creature’s background 18 are achieved; on no other basis could they be achieved, or would they greatly avail the animal. (See, however, the definition of Mimicry in Chapter II.) The reader who has assimilated what we have said thus far, is now in a position to perceive the fallacy of the statement, prevalent in former years, and still made by certain writers, that a protectively colored animal of the type described above escapes detection because, being of a dull-brown color like the ground and the bushes, it looks when it sits motionless like a clod or a stump—or some such inanimate thing. For clods and stumps are solid objects of a uniform tint, and manifest to the eye, by the laws of light-and- shade, not only their solidity, but all their smaller modelings. They are not inconspicuous, except in so far as their great abundance makes the eye in- attentive to individual ones. The protectively colored animal, on the other hand, is, as it were, obliterated by his counter-gradation of shades, and in the cases where he escapes notice, it is by virtue, not of the eye’s perceiving his solid form, and taking it for that of an inanimate object, but of its failure to recognize it as a solid object of any kind, seeming, if it rests on it at all, to see through it to what is beyond. For the animal looks at most like a flat plane interposed between its background and the observer; and since actual flat foreground-planes of this kind at right angles to the earth do not com- monly exist in the woods and fields, the eye usually interprets the animal’s surface as part of the scene, ground-plane or wood mass, simple or com- pound, which lies beyond it. If these animals were merely brown or gray like clods and stumps, they would not be concealed, because their structural forms are too distinct, and the eyes of enemies are keen to detect their charac- teristic ‘modeling’ and outlines. On the other hand, a perfect shade- gradation, even of some rankly brilliant color, would go far toward concealing an animal, for he would still have no appearance of solidity; and any varied landscape, especially a sunlit one, even in the dingy temperate zone, is full of patches of brilliant color, as all artists know.* * A large expanse of any strong color, as the green of the foliage, begets in its interstices and on its borders an appearance of its ‘‘complementary.” It is partly for this reason, as an American 19 A striking revelation of how completely the inconspicuousness of counter- shaded creatures depends upon their counter shading, may be had even more easily than by experimenting with models, merely by holding such a creature upside down, in its normal lighting, and against its normal background. It will be seen not merely that its ghostly dimness has vanished, but that it is extraordinarily conspicuous—just doubly as conspicuous, in fact, as any stick or clod placed in the same position would be. For an inverted animal not only lacks counter shading, as a stick or clod does, but is even fully shaded the wrong way—brightest where it catches most light, and darkest where it catches least. No other conceivable arrangement of colors could make an object as conspicuous as this. Yet an animal held thus inverted is, materially, as truly “colored like his surroundings” as he ever was. It might be thought that such creatures are usually seen from above, so that their light-colored undersides are out of sight, and that only their wpper parts, which always show, are supposed to be colored like their surroundings. ‘To this there are two cogent answers: In the first place, many of these creatures, such as the various forest Grouse, are at their best when perched high above the ground, so that the under side is at least as fully exposed as the upper. In the second place, the colors of those which stay on the ground must surely serve as a protection against the ground animals, which move about on their own level, as much as against those which see them from above, as do hawks and men. This last is a very important consideration, with which we shall have to deal again later in the book. In speaking of the elements of visibility, I have already referred to the fact that color—apart from light-and-shade—is a secondary factor in the visibility of the ‘modeling’ of solid objects, and have spoken of the tendency toward a bluish coloring of the more directly sky-lighted portions, and an orange coloring of the reverse ones. The working of this principle on the bodies of animals is very pronounced, and the counter gradation of their tones would ornithologist, Mrs. F. H. Eckstorm, has very truly said, that the gorgeous Scarlet Tanager is not conspicuous in the green woods. 20 not be perfect if it did not include a delicate gradation of actual color, from brownest above to bluest below, to cancel the effect of the bluish sky-light and shine on their upper surfaces, and the brownish shadow, with brown earth- reflections, on their lower. Cold white is usually required for the bright climax of the shade gradation, and cold white amply meets the color require- ment also. It is likely that few but artists will feel the validness of our state- ment of this subtler element of the principle, although anyone can learn to see the existent gradation of ‘color’ on most counter-shaded animals. The reader has now been given a fairly exhaustive description of the main elements of the new principle, which through its various windings and with its various remarkable concomitants we are about to follow into several branches -of the animal kingdom. Among the lower orders, it is more or less largely supplanted by another great principle, namely, that of Mimicry, which we will define and differentiate in Chapter II. Before closing this introductory chapter, however, we must give an account of the earlier, independent partial discovery of the principle of counter shading in the animal kingdom, by Prof. Edward B. Poulton, of Oxford University. Professor Poulton has been one of my father’s most enthusiastic listeners, and is one of the few naturalists who have given proof of completely under- standing the subject. In his introduction to my father’s article in Nature he generously seeks to minimize the importance of his own partial predis- covery of the principle. The case is thus stated by my father in the above-mentioned article: “Since publishing my papers in ‘The Auk’ for April and October, 1896, I find that Prof. Poulton perceived years before their appearance the power of a counter-grading of light to make the round surface of a pupa appear flat, and in another case the power of light color in a depression to make the concavity disappear. In both of these cases he perceived the very Law of Light-and-Shade on which the fact of Protective Coloration rests, and recognized the fact itself in these instances. In his ‘Notes in 1886 upon Lepidopterous Larve, etc.,’ read April 6, 1887, he says (Trans. Ent. Soc. Lond., 1887, p. 21 294), ‘Although the cleft (between the posterior part of the body of the larva of Rumia crategata and the branch) is largely filled up, . . . a considerable furrow remains, but this is not apparent because of the light color of the fleshy processes, which prevent the attention from being directed to the shadow which would otherwise indicate the position of the groove. The processes, therefore, attain the object of softening the contact between the larva and its food-plant in a two-fold manner, by partially filling up the cleft and by neutralizing the shadow in the groove which remains. I have also noted the processes in the larva of A. betularia, and I believe that they are of very general occurrence in Geometre.’ “His other case is to be found in his ‘Notes in 1887 upon Lepidopterous Larve, etc.,’ read October 3, 1888. He says (Trans. Ent. Soc. Lond., pp. 595-6), ‘The most extraordinary thing about this resemblance (of the pupa of A patura iris to a sallow-leaf) was the leaf-like impression of flatness con- veyed by a pupa which was in reality very far from flat. Thus the length of the pupa was 30.5 mm.; the greatest breadth (dorso-ventral diameter) 11.5 mm.; the greatest thickness (from side to side) 8.5 mm.;... But exactly in these places, where the obvious thickness would destroy the re- semblance to a leaf, the whole effect of the roundness is neutralized by the increasing lightness of these parts—a lightness which is so disposed as to just compensate for the shadow by which alone we judge of the roundness of small objects. (Much larger objects can be judged of by the change of focus, which becomes necessary as their near or distant parts are observed.) In shading the drawing of an object so as to represent roundness, the shade is made to become gradually less and less deep as the tangential planes repre- sented come nearer and nearer to a right angle with the axis of vision. So here, the converse of shading—the whiteness neutralizing the shadow which shading is intended to represent—dies off gradually as the (representation of the) mid-rib is approached. “The whiteness is produced by the relative abundance of white dots and a fine white marking of the surface which is present everywhere, mingled with 22 the green. The effect is, in fact, produced by a process exactly analogous to stippling. “*By this beautiful and simple method a pupa, which is 8.5 mm. from side to side in its thickest part, appears flat and offers the most remarkable resemblance to a leaf which is a small fraction of 1 mm. in thickness.’ ”’ 23 CHAPTER II DEFINITION OF TERMS. ILLUSTRATIONS OF OBLITERATIVE COLORATION EFORE going further we must clearly establish and define the special descriptive terms which are to be used in the course of the book. The term, ‘‘the law which underlies protective coloration,” as applied to counter shading, was inexact, since ‘‘ Protective Coloration” of course includes not only concealing-colors based on this newly disclosed principle, but many branches of the entirely different principle of Mimicry, as well.* A name even more to our present purpose than Protective Coloration, for the com- prehensive meaning, would be one which should include all modifications of the bodies of animals, both those of form and those of color, whose ob- ject seems to be visual deception of any kind. This would make room for offensive as well as defensive mimetic resemblances, etc., and for the many curious cases of protective form modification, most common among the lower orders of animals. But we are to have so little to do with these partially extraneous principles that we need not discard the old and familiar term, Pro- tective Coloration. Interchangeably with it, however, we shall use others some- what more comprehensive, viz., Disguising Coloration and Disguising Costumes. * Throughout our book we shall use the word Mimicry in a wider and perhaps looser sense than that in established use among zodlogists, and we herewith offer an apology for this innovation. In order to emphasize tersely the fundamental difference between ‘Obliterative Coloration’ and both the principles involving imitation of definite objects, which principles have been known re- spectively as Mimicry and Protective Resemblance, we have found it necessary to join the two last mentioned under the general head of Mimicry. Derivatively, the name is nearly as applicable to one as to the other, and the limiting it to the simulation of the colors and forms of animate creatures by those of other animate creatures, in contradistinction to the imitation of inanimate objects, is more or less arbitrary. The two phases are closely related, and for our present purposes must be consid- ered as different branches of one principle, which can only be called Mimicry. 24 Fic. 1. Two bird-models, just alike cxcept that the one on the left is counter-shaded, the other’ not, though covered uniformly with the very iaterial of its background. This right-hand model, therefore, is actually as light below as above. Fie, 3. ie, 2. Obliteratively-shaded bird-model, as in Fig. 1A, but inverted. (Somewhat side-lighted, ) Fic. 4. Two hird-models as in Fig. 1, but out of doors against bare ground. The one ou the right is obliteratively-shaded, the other not, Fic. 5. Two bird-models precisely as above save that the right hand one is still better ‘obliterated.’ The reader will have to take it on faith that this isa genuine photograph, and that there 7s a right-hand model of the same size as the other, unless he can detect its position by its faint visibility in Fig. 4. Bird-models as in Fig. 1, but with the top-light eut off from the obliteratively-shaded one, A. Protective or Disguising Coloration, then, as we define it, falls into two main divisions; the one including concealing-colors mainly based on counter shading, and the other including Mimicry, in almost all its branches. As has already been explained, the goal of the former principle is the rendering animals invisible in their normal haunts. Mimicry, on the other hand, aims at deceptive visibility; it makes an animal look like something else than what it really is. It will be seen that the latter principle is open to unlimited varia- tions of method and result, whereas the former, as we have proved, is in its main essentials strictly limited. ‘There are innumerable kinds of solid objects for animals to simulate in appearance, but there is only one way to make a solid object in a natural lighting cease to appear to exist. Both these are principles of disguising costume, and both are protective, yet they are funda- mentally unlike. It becomes necessary to find a fully adequate name for the stricter principle—a name less technical and more explicit than “counter gradation.” Obliterative Coloration is a phrase that will fit the general principle, and Obliterative or Counter Shading may be used as a stricter term for the essential root of it. We have, then, Obliterative Coloration, and Mimicry, as the two main prin- ciples of Protective Coloration. Of the well-known and well-studied prin- ciple of Mimicry, we shall give but few examples, and these chiefly from among the lower orders. In the higher orders, it seems, as we have said, to play a very insignificant part. Figs. 1-5 illustrate obliterative shading, pure and simple. Fig. 1 shows an obliteratively shaded artificial model, contrasted with a monochrome one which is colored precisely like the background, being covered with the very same material; Fig. 2 shows a counter-shaded model inverted, and Fig. 3 the two models in the proper position, but with the direct top-light cut off from the counter-shaded one. Fig. 6 shows a Barred Plymouth Rock hen, a bird which completely lacks obliterative shading, photographed, out of doors, against a background made wholly of the flat skins of similar hens. A more striking demonstration of 25 the powerlessness of mere similar colors to conceal could hardly be devised. So, were it not for his obliterative shading, would the leopard or jaguar show up in the forest, despite his richly spotted forest-pattern. Fig. 7 shows a pure white hen, photographed against a white cloth, an- other illustration of the ineffectuality of mere color-resemblance. The hen is conspicuously solid, her back showing light and her belly dark against the flat white plane of the cloth. Every part of her surface, in fact, except for a few mere points of transition, is either too dark or too light to match her back- ground. A ptarmigan in winter plumage lacks the advantage of counter shading, and must needs lack it, since even the middle of its back has to be white to match its pure white snowy background,-and nature can furnish nothing Jighter than white feathers for the bird’s underside. But the up- ward reflection from the snow itself goes far toward canceling the shadow on such animals. (See Figs. 8-10.) In the same way the reflection from bright sand codperates with the delicate counter shading of desert animals, which are usually very light colored. Such creatures are also as a rule al- most unmarked, and thus furnish good examples of the use of obliterative shading, pure and simple. It is on a delicate scale, however, since there is but a short range of shade between pure white and the delicate brown re- quired to make the animals’ backs ‘coalesce’ with the sand. Desert animals are of course habitually exposed to full sunlight, but the excess of shadow which the undersides of sunlit animals normally bear,* is in this case almost or quite counteracted by the light-reflecting power of the bright desert sand. Many forest animals, on the other hand, wear a slight counter shading at the dark end of the scale—that is, from some dark color to a very slightly lighter tone—because of the extreme diffuseness of the light in shady forest recesses, whose colors are mainly dark and rich. The need of extreme counter shading —from very dark to purest white—seems restricted mainly to high-standing animals which live in the open on dark ground. On such a one the direct sky-light makes its full graduated shading, and the shadow of the undersides *See p. 18, Chapter I. 26 Fic. 6. Plymouth Rock hen—a bird which lacks counter-shading—against a flat background of Plymouth Rock hen skins, demonstrating the same thing as Fig. 7. Photographed from life. Fi. 7. White fowl, lacking counter-shading, against a flat white cloth rome object can not be ‘obliterated,’ no matter what its Clemuad: CE Se eee Photographed from life. i ¥ 4 j hy y 4 Lot Fic. 8 Rocky Mountain White-tailed att in winter plumage, on snow, and favorably lighted for inconspicuousness. Rotundity as dimly apparent as is possible ri without counter-shading. Photographed from life by Edward R. Warren. Fic. 9, Rocky Mountain White-tailed Ptarmigan, in winter plu- mage, off snow. Their rotundity, revealed by their lack of counter- shading, ismarked. But they may still pass for lumps of snow. Photographed from life by E. R. Warren. Fic. 10. Rocky Mountain White-tailed Ptarmigan in winter plumage, on snow, but unfavorably lighted for inconspicuousness. : Photographed from life by E. R. Warren. is not alleviated by upward reflection; while the highly illuminated back has to be of a very dark tone to coalesce with the dark earth, rock, or whatever it may be that forms the animal’s normal background. These examples serve to illustrate the law, almost or quite infallible, that the range and scale of an obliteratively colored animal’s counter shading de- pend on the ratio of the average brightness above it to the average darkness beneath it, in its normal haunts. Thus, to recapitulate, we find on sandy deserts birds, mammals, and reptiles counter-shaded from sand-color to white, while on dark-colored open ground we find them shaded from very dark to white. (Of this last class the smaller Wood Sandpipers (Totanus), which live on muddy stream and pond banks, are excellent examples. So also, in a cruder form, are some of the Oyster-catchers (H@matopus) and Stilts (Himantopus), whose counter shading consists of two tones only, black and white. Among mammals, examples are the darker-backed hares, deer, kangaroos, etc., which live more or less fully exposed to the sky-light on rather dark ground.) Where the sky-light is intercepted and diffused by foliage or other natural obstructions, as on the ground under grasses, bushes, etc., on marsh-land under reeds and rushes, and, most of all, in the forest, we find many rich or dark-colored animals with a weak obliterative shading (one, namely, whose bright climax comes more or less short of white, being even in some cases but slightly lighter than the tone of the back). Many of the for- est-inhabiting passerine birds of Europe and America wear this form of coun- ter shading, as do also certain forest grouse, as well as squirrels and other mammals; while among tropical birds it is well represented by many green parrots and parrakeets, etc., and also by many brown species that inhabit the gloomy interiors of the great forests. Some of the ground sparrows, and the rails, are good examples of the grass and swamp forms, while the female of the European Blackbird (Merula), and the North American Catbird (Galeo- scoptes) may be cited as examples of the thicket-haunting form among fa- miliar birds. This indisputable fact, that animals tend to be dark in thickets and dusky forests, and pale on the glaring desert, and on ocean beaches, is a 27 complete refutation of the theory that the counter shading is due to the tan- ning effect of light. On the other hand, the idea that the paleness of desert creatures is due to bleaching, is equally well answered by the fact that their shadowed undersides are still the lightest, as in the case of almost all other animals. Figs. 11-13 show photographs of the skins of various birds and mammals, split longitudinally through the lower median line, and spread out flat. This is a simple and adequate way of exhibiting the exact character of the obliter- ative shading of animals. The names of the species thus represented are given under the pictures. It will be seen that some beasts which are usually considered practically monochrome, such as the Mink (Putorius vison), have in reality a slight counter shading. (See footnote, p. 123.) Pictures of protectively colored wild birds and mammals in situ cannot be really true to Nature if they represent them as having the light-and-shade of normal solid objects—a fault usually committed by illustrators, who study them in unnatural situations, such as the cages of a menagerie, or other places where the illumination fails to codperate with their counter shading. These paintings of ours (grouse, rabbit, snake, caterpillars, etc.) are intended as examples (outside the field of photography) of trwe animal illustration—ren- dering instead of defeating the wonderful obliterative effects of their counter shading.* . Of course so new a lesson cannot be learned all at once by the world at large. But when the truth on any subject has once been started, it cannot fail gradually to supplant the previously existing errors. It will be many * Japanese and Chinese art almost entirely dispenses with light and shade, dealing solely with line and color. Japanese pictures of birds and mammals, therefore, represent, approximately, the animal’s actual color tones, quite irrespective of shading. A white belly, for instance, is painted as bright as a white back. Thus these Oriental renderings of animals are actually, in one sense, more realistic than the Occidental, because by their complete lack of shading they approximate the won- derfully unsubstantial look of the birds and beasts in Nature. An object which shows lighter on its lower border than its upper, under the light of the sky, cannot possibly look solid. It looks at most like a party-colored flat (or concave) surface, rather than a rotund body. 28 Fie. 11. Fie. 12. Fies. 11 and 12, Mammals’ skins spread out to show oblit- erative-shading. Fic. 11. Spotted Seal (Phoca vitulina.) Fie. 12. Cotton-tail Rabbit \Zavus floridanus transitionalis. ) [Cf above.] Fic, 18, Birds’ and mammals’ skins spread out to show obliterative-shading, continued. The species are as follows: Beginning above, left, Blue Jay (Cyanocitta cristata), Tree Swallow (Tachycinetia bicolor), Pine Grosbeak (Pinicol leat densis, female), Common Chipmunk (Tamias striatus) Mink (Putorius vison), English Sparrow (Passer domesticus, female), Lesser Whitethroat (Sylvia cur TUCH) , two kinds of shrew-mole, names (?) jumping mouse (Zapus hudsonius, stuffed skin, side view) Am, Siskin (Spinus pinus), Gray Squirrel (Sciwrus carolinensis), Muskrat (Fiber zibethicus) and sharp— shinned Hawk (Aceipiter velox, young female). years, no doubt, before a drawing with conspicuous light-and-shade of a live sandpiper or rabbit in Nature is looked upon as an absurdity—and yet that time must surely come. Having considered obliterative shading, pure and simple, we will now advance to the next stage in the study of obliterative coloration, namely, the use of markings on counter-shaded animals. The first few chapters will deal chiefly with artificial models. 29 CHAPTER III FIRST PRINCIPLES OF THE USE OF MARKINGS WITH OBLITERATIVE SHADING HE need of markings is a natural concomitant of the principle of ob- literative shading. When an unmarked solid object in a given lighting has been reduced to a perfectly ‘flat? monochrome by counter shading, so that it lacks all visible attributes of solidity, it may be quite undistinguishable, provided that its background is of a similar monochrome flat tint. Such is the case in Fig. 14. The solid model is almost undistinguishable, seeming merged into the flat plane of the cloth-covered board, which in reality is several yards behind it. Complete ‘obliteration’ has taken place; for the model, having no dis- tinctive light-and-shade, color, or surface character, is as it were absorbed into its background, and the space in which it stands seems occupied by empty air. But if we now apply a pattern to the background, as in Fig. 15, the case is changed. Though still unsubstantial-looking, and very inconspicuous, the model is clearly discernible as an interruption of the background-pattern. If this pattern is small and regular, as in our figure, the whole of the unmarked object’s characteristic outline may be traced against it, and by the process of mental inference already alluded to, the observer will recognize it, in spite of its ghostly flatness, as a solid body between him and the background-plane. But behold the effect of applying a like pattern to the model also, as in Fig. 16! It immediately recedes again into the flat plane, and the eye loses it even more surely than before, because its likeness to its background is now positive and graphic, at many points. The foregoing figures illustrate the simplest form of the use of markings in codperation with obliterative shading. The next thing for us to consider 30 Fig. 14, Obliteratively-shaded bird-shaped model against plain background, (Defective photograph, retouched. The model might show even less, in reality. Cf. Iigs. 4-5.) Fic. 17. Spotted, obliteratively-shaded bird-model, as in Fig. 16, but wrongly lighted. ‘his picture shows the depeni/- ence of the part played by pattern in the obliteration of leopards, zebras, etc. Without counter-shading, these animals would look conspicuously solid, despite their patterns. Fic. 15. Bird-shaped solid model, obliteratively-shaded in full, and correctly lighted, but revealed by its blank silhouette against a spotted background. Photograph. 16._ Bird-shaped, oblitera- haded model, as in Fig. 15, but concealed by the addition of sputs like those of its background. Photograph. is the matter of pattern perspective. The elucidation of this will mark another step in the differentiation of obliterative coloration from all forms of mimicry. For it will show that not an exact reproduction of the actual background- pattern, but a picture of that pattern as it looks when more or less altered and refined by distance, is essential to the concealing of an object. Or, in other words, ‘that the object’s obliteratively-shaded surface must bear a picture of such background as would be seen through it ij it were transparent. The diagram, Fig. 18, represents a flat, bird-shaped model, vertically placed, seen against a horizontal background. The background-pattern is supposed to be actually uniform throughout, but diminished to the eye as it recedes on the horizontal plane. The model, vertically interposed between the eye and this receding ground-plahe, must, for concealment, bear a pattern graduated from larger on its lower borders to smaller on its upper. For the highest parts of the model are seen against the most distant and therefore most dimin- ished portion of the uniform background-pattern—and vice versa. Further- more, the markings of the background, being on a receding plane, are jore- shortened throughout, and this effect also must be imitated on the model. These diagrams and photographs will serve to illustrate, in a crudely sim- plified form, some of the main principles of obliterative pattern which prevail in Nature. Instead of one unvaried pattern on a single plane, however, Nature furnishes backgrounds of rich diversity. Mud, grasses, pebbles, bushes, tree- trunks, branches, leaves, living and dead, and vistas amid vegetation to the bright sky beyond—these, all of them subject to endless variations of com- minglement, of distance, and of lighting, are a few of the numberless details of the backgrounds against which ground-haunting animals are seen. To achieve the highest degree of inconspicuousness, these animals must wear, superadded to their obliterative shading, yet in the main conforming with it, a sort of compound picture of their normal backgrounds—a picture seemingly made up by the averaging of innumerable landscapes. Further, this land- scape-picturing must be suited variously to different portions of the animal’s surface. The top-planes, being seen in full only against the nearer ground, 31 must bear a larger pattern than the sides (see the second diagram, Fig. 19), which are seen against more distant ground or forest landscape, with details reduced and altered by perspective; and the highest portions of the side-planes, e. g., the sides of the animal’s head, being seen, in the long run, against the most distant backgrounds, must have the finest pattern of all. Codperant with these principles is the fact that the pattern looks different on receding planes of the solid object. Thus in the side view all that shows of the neces- sarily coarser top-pattern is so refined and narrowed by perspective that it is fully equivalent to the actually finer pattern of the sides. In the reverse case, the side-pattern scarcely shows at all. Nature’s achievement of this ultimate perfection of obliterative coloration, on birds, is the subject of our next chapters. 32 = ip hs Cel AE Fic. 19. Diagram supplementing Fig, 18, showing the coarser back-pattern, required to match the ground- pattern un-foreshortened and almost undiminished, as when seen from directly above. Fig. 18. Diagram showing the punarny of perspective by animals’ patterns. The hird is supposed to he vertically placed, and looked some- what down upon against a uniformly patterned horizontal ground-plane. Fic. 21. Shows particularly well the head-markings’ picturing of a shadowed cavity crossed by lighted twigs or grasses. eerie 20-21. American Woodcock on its nest; showing the working of the wonderful obliterative picture-patterns, founded on counter- ‘sloop jo yuo sp.arq puap wor paydeasojoyg Surpeys daNRaay[qo ay) Jo BULyAOM [RULIOT aq] AO) sTOT]SOd BnocK ULasnRoad snonotdsaoa TOY CaMayTaA yseaty “EE EMOTA pe fy Tops STE oO yooapoo sy peaqe “a Pury ‘ Fe OTL ay 2, > “your 2 g) Me Od, }dv13040y >t Sot Aq papraaat wo youq oy yep sv ‘UMOIg payuUy d AVen aay Tet od “w1a}yed-ainyord SHE QUEM yNq ZZ BL rp oy! we posod Yooopoo Ay Peo, SIOVUNO,) "SOU S}T UO (More DLaYOL NY) Yoopooyy, Uvoowy “3 OL CHAPTER IV BACKGROUND-PICTURING ON OBLITERATIVELY-SHADED BIRDS. FIRST TYPE, PICTURING OF THE LARGER DETAILS OF THE NEARER GROUND, ON TERRESTRIAL BIRDS EREWITH we leave the arid field’ of demonstration with artificial models, and launch into the wonderland of actual Nature. If we compare the numerous cases of evident background-picturing on the bodies of obliteratively-shaded birds, we find that they are clearly separable into several main classes or divisions. Many of the species, for instance, have a wonderfully minute and intricate pattern, while others, almost equally famous for their ‘invisibility,’ are marked in a much simpler and more blotchy way. The finely-patterned class is again divisible into two very different ‘branches, as we shall see later on. This chapter, as the heading indicates, is to be devoted to the more blotchily-marked type of pattern-bearing ‘In- visibles.’ The best examples of this type are terrestrial birds which live among fallen leaves and sticks, etc., or among weeds and grasses, patches of mud, and pools of water. Preéminent among them are the Snipes and Woodcocks (Philohela, Gallinago, etc.),—Figs. 20-26. The American Woodcock (Philohela minor) is a beautiful representative of the class. See Figs. 20-22, reproduced from photographs of live Wood- cocks in Nature, and Figs. 23-24, which show photographs of a dead Wood- cock against a normal background, but with its obliterative shading variously upset. In Fig. 24A, the bird is on its side, with its back toward the spectator. Thus the largest expanse of its pattern is exposed to view, yet it completely fails to obliterate, chiefly because it is no longer aided by a proper light-and- shade gradation. Fig. 24B shows the same bird with wnder instead of upper side exposed—in which position it is of course even more conspicuous. Fig. 33 23 shows the bird, with the general shade of its back artificially extended over its sides and belly, posed to simulate as nearly as possible the attitude of the . live bird on its nest represented in Fig. 22. The contrast between the two, as to conspicuousness, is most pronounced.* No clearer elucidation could be devised of the pattern-principle in ques- tion than is furnished by the photographs of live Woodcock and Snipe (Figs. 20-22 and 25-26). The imitation of the larger details of the squatting bird’s near background is exquisitely perfect, particularly. in Figs. 22 and 25. Dead leaves, twigs, and grasses, variously disposed over shadow-holes, in a near view, are the main components of the pattern-pictures which such birds wear. Because they are strictly terrestrial and rather sedentary, in time of danger usually squatting motionless on the ground, and allowing enemies to approach them very closely before they fly, they are almost always seen against a comparatively near portion of the ground-plane, and hardly ever against a highly diversified forest landscape. Hence a picturing in slight reduction of the simpler ground-pattern of leaves and twigs, etc., com- mon to all the bogs and coverts which these birds inhabit, is all that is needed for the complete ‘obliteration’ of their counter-shaded bodies. Many other examples of this class of background-picturing could be cited, but the ones already given will suffice. That most beautifully patterned bird, the European Woodcock (Scolopax rusticola), belongs in a distinctly different class, and will be considered later on. * These four pictures (Figs. 22-24B) are reproduced from the article in the Awk mentioned in our preface. 34 Fic. 25. Wilson’s Snipe on its nest; ‘obliterated’ by counter-shading and Biome pattern (representing sticks, grasses, etc., with their shadows, at various istances. ) Photographed from life by Herbert K, Job. Here reproduced by courtesy of Houghton, Mifflin & Co. Fic. 26. Jack Snipe (Gallinago caelestis.) Still more specialized ‘picturing’ of straich ight stick dead reed stems, or broad grass-blades) and shadows, [Cf. the Chipainnk Figs iB and o3) © Se ae Photographed from life by Cherry and Richard Kearton. Courtesy also of Cassell & Co. Fic. 27. Nesting Whip-poor-will. [Cf. Fig. 28.] Photographed from life by Herbert K. Job. Fic. 28. Whip-poor-will (Antrostomus vociferus) on its nest. Near-ground-‘picturing’ patterns of the minutest type, founded, as always, on obliterative shading. Photographed from life by Rett E. Olmetead. CHAPTER V BACKGROUND-PICTURING ON OBLITERATIVELY SHADED BIRDS, CONTINUED. SECOND TYPE,—INTENSELY ELABORATE PICTURING OF THE MINUTE DETAILS OF THE NEAR GROUND, ON TERRESTRIAL BIRDS HERE are two main types of intricate-pattern background-picturing, as there are two classes of minute forms and markings in field and forest landscape. The one consists of the actually minute markings of the various inanimate objects, such as leaves, logs, sticks, stones, grasses, etc., seen at very close range; and the other of the cruder forms of large objects and groups of objects, such as tree-trunks and branches, and sky-vistas, reduced and refined by distance into a delicate pattern. Marvelously fine and intricate patterns, rendering with almost microscopic minuteness the aspect of dead leaf and mossy log surfaces, seen at extremely close range, with an admixture of somewhat more distant ground-vista pictur- ing, are worn by such birds as the terrestrial forest Goatsuckers (Caprimulgide), which are almost: unique among birds in their evident extreme dependence on obliterative coloration. Squatting motionless on or near the ground in the depths of shady forests, they take wing only as a last resort, when almost trodden upon by an enemy. In conformity with this habit, their obliterative pattern is developed to a point of minutely detailed realism quite beyond that of such well-concealed ground birds even as the American Woodcock. It is as if the Woodcock wore an adequately true facsimile of the main effect of its dead leaf and stick background, with the smaller markings of these ob- jects largely omitted, while the Goatsucker wears a similar pattern-picture carried out to the last degree of finish, with all possible minute details faith- fully represented. The intricate bark- and lichen-pattern of the surface of a fallen log, the reticulations of dead leaves,—all the innumerable delicate mark- 35 ings discernible upon close scrutiny of the forest ground, together with the larger pattern formed by groups of slightly more distant leaves and twigs, etc., with their high-lights, their middle tones, and their dark shadows,—all these things, variously reduced by perspective, are clearly suggested to an appreci- ative observer by the marvelous patterns of the forest Caprimulgide. The fact that none of these detail-picturings is so patently realistic as to be appreci- able to everyone when the bird is seen away from its natural environment, is part of the very marvel of the thing. Thanks to some process * which in its visible results has amounted to something like an averaging of all the normal backgrounds, against which, from aboriginal times, the animals have been seen, they bear a pattern precisely similar to none, yet amply fitting all. This effect of perfect averaging or compounding is one of the most beautiful and es- sential parts of the obliterative principle. (In certain cases, which will be considered later on, an animal’s background is subject to so little variation that a more simple and single imitation of absolute details is possible.) Though fully developed, the obliterative shading underlying this pattern- system of the goatsuckers is slight in range, conformably to the diffuseness of the top-light in deeply shaded woods, which these birds inhabit during the day. True obliterative coloration perhaps makes its nearest approach to mimicry among animals bearing this form of pattern. For while the coun- ter shading as well as the character of the markings proves the case to be one of obliteration, or merging with the background, yet the apparent extreme nearness of some of the pictured details, which in certain views will even ‘co- alesce’ perfectly with the markings of the very object on which the animal is sitting, such as a stone or mossy log, gives the phenomenon, in part, close kinship with the exact mimicry of surface-detail on an animal whose protec- tion is the simulation, with full appearance of solidity, of a single inanimate object. It is furthermore undeniable that a finely-patterned bird such as we have been describing does occasionally pass for an excrescence of the log or rock on which it sits. This may be the case, for instance, when it is seen in * We ourselves attribute all such work to natural selection, pure and simple and omnipotent. 36 Fic. 29. Nighthawk—a percher in the open, on lichen- freckled rocks, tree boughs, etc. Near-ground-picturing of the minutest type (based, of course, on obliterative shading.) Photographed from life by J. E. Seebold. Fic. 30. Nesting Nighthawk. ([Cf. Fig. 29.] Photographed from life by Ora K. Knight. Fic. 31. Ruffed Grouse walking. ‘Obliterated’ by its highly- wrought picture-pattern, based on complete obliterative shading. Photographed from life by James R. Miller. Fic, 32, Nesting female Ruffed Grouse. Photographed from life by James R. Miller. full side-contour against an unfavorable background, especially if its mark- ings do not clearly show. For, we repeat, these markings, though pictures of comparatively near details, are still pictures, in the sense of representations of patterns beyond the animal, and not exact facsimiles of the surface-mark- ings of any object. It must be remembered that a large class of the enemies of such a bird, namely, the terrestrial carnivorous quadrupeds, which ap- proach it on its own level, usually see it against a more distant background than do we tall bipeds who look down upon it. In accordance with this fact, it will be found that there is more than one would at first suppose of the ele- ment of distant background picturing in the side-markings of most terrestrial birds. But even if it is merely the thickness of an animal’s counter-shaded body which habitually intervenes between its exposed side and the seeming background pictured by its markings, the principle is not mimetic, according to our nomenclature. To complete the statement, we must add that no ani- mal bearing. a full obliterative shading can, under normal conditions, pass for some other kind of solid object, but must appear either as a flat plane, or as merged into the scene behind it, whether near or far,—the smallest possible extent of its apparent retrocession being a distance corresponding to the thick- ness of its own body; but in order that it may completely undergo such ‘ob- literation’ the pattern which it wears must always be smaller than the actual pattern of its background. Figs. 27-30 need no explaining in the text. 37 CHAPTER VI BACKGROUND-PICTURING ON COUNTER-SHADED BIRDS, CONTINUED. THIRD TYPE,—-PICTURING OF THE MORE DISTANT BACKGROUND ON PARTIALLY ARBOREAL BIRDS T is obvious that high-standing and tree-perching birds tend to have more distant ‘backgrounds’ than do those that squat on the ground, and that in many cases the only pattern which could adequately codperate with their obliterative shading would be one which should ‘coalesce’ with a highly diver- sified forest-interior landscape. A landscape, that is, made up of tree trunks and branches, near and distant, the interminably various criss-cross pattern of the smaller twigs, stretches of sunlight-dappled ground, glimpses of sky, etc.,—or, in other words, the second type of intricate pattern named in the preceding chapter. Such a pattern exists on many birds, and when, as in nearly all the cases, it is to some degree commingled with a representation of the nearer details of the ground-plane, to suit its wearer’s partially terrestrial habits, it marks the very consummation of the obliterative principle. Certain forest grouse, such as the Bonasa umbellus or Ruffed Grouse of North America, and the Hazel Grouse (Bonasa betulina), of Europe, are perfect examples of this type. The colored plate represents a cock Ruffed Grouse, against a variegated forest interior. ‘This picture, as stated in the Preface, was painted from woodland photographs, etc., and from a stuffed grouse in a house-lighting artificially arranged to suit the bird’s counter shading. Notice his complete lack of light-and-shade indicative of solidity—by which lack his beautiful ground- and-forest markings are enabled to ‘coalesce’ effectively with those of his back- ground. Such—or even more magically obscure—is the aspect of a live Ruffed Grouse in a naked tree, which the eye of the hunter scans in vain at- 38 EXPLANATION OF PLATE II MALE RUFFED’ GROUSE IN THE FOREST. Painted by Geral Sli Ski GEE Te AN PLATE II ANOEN 8:00. BALUMORE . tempt to detect its ghostly form. The bird is in plain sight, but invisible— such is the wonderful power of full obliterative coloration. Nature has, as it were, used the bird’s visually unsubstantialized body as a canvas on which to paint a forest vista. In this there is nothing of mimicry, as we define it. Mimicry uses the solid aspect of an animal’s body, modified in form and color, to simulate some other solid object. But vista- or background-picturing, based on the complete obliteration of the animal’s solid aspect, which causes its actual form to pass for an empty space, is a widely different principle. Even in the terrestrial moments of the Ruffed Grouse’s life, it is usually seen against more distant backgrounds than are the Goatsucker and Woodcock, because it largely lacks the squatting-habit, except in the case of the young, or the female sitting on her eggs. (See Figs. 31-33.) Noteworthy in this connection is the fact that the markings of the sexes are decidedly unlike. In the female, the most critical portion of whose life is probably the annual three weeks’ brooding on her ground nest, the blotchy near-ground pattern pre- dominates over the forest-vista pattern; whereas in the male it is just the other way. It is difficult or impossible to distinguish the two styles of pattern absolutely in either case. But they are so adequately commingled, in one or the other predominance, that, however the bird is placed, some portion is almost certain to coalesce perfectly with its background; and with this key- note of complete obliteration the remainder of the pattern amply serves its purpose. Indeed, not even this degree of actual immediate ‘matching’ is necessary for the bird’s concealment. His costume is a sort of patchwork of pictures, subtly intermingled, each an epitome of some particular type or detail of woodland scenery. Such details and bits of landscape are charac- teristic of the place in general, and even when those furnished by the grouse’s pattern are unmatched by any in his immediate background he is not apt to be revealed. Only an artist, perhaps, can rightly appreciate the profound and perfect realism of these background-pictures worn by birds and other animals. Just as a good caricature drawing of a man looks in one sense more like the man than the man himself, so, in a far more high and wonderful 39 degree, do these pictures on animals’ coats exceed the verisimilitude of the actual scenes they imitate. They have been compounded and epitomized and clarified till only pure, essential typicality remains. The difference may be stated tersely thus: On the one hand, we see a stick, a leaf, a web of twigs over the sky; on the other hand, we see stick, leaj, web of twigs over sky. Just as in great human art, but far more essentially and surely, the trivialities "and chance individual abnormalities have been eliminated, or subordinated to the scheme of ultimate, impartial typicality. To learn, then, the purely characteristic colors and light-and-shade effects of leaves and sticks and stones and other parts and types of natural scenery, we should look not at the scenes themselves, but at the animals whose patterns picture them. The essential realism of these pictures is such as the keenest artist among men could never hope to match. Nay, for Nature herself has made them—Nature herself has discovered and applied, to a point utterly beyond human emula- tion, the art of painting pictures. Let us recur once more to the Ruffed Grouse. The transverse barring of its breast and flanks, a form of marking common to a majority of the larger birds inhabiting northern forests, closely imitates the appearance of hori- zontal branches seen at rather short range. Such branches are a very im- portant feature of coniferous forest scenes. When this barring occurs on the underside of a forest bird, it is almost invariably continued by a series of spots on the outer webs of the primary wing-feathers. These spots become confluent when the wing is folded, and thus the large-branch-picturing is made to extend almost uninterruptedly across the bird. (See the colored plate. Our grouse, however, was rather weakly barred underneath.) The beautiful oval-spotted pattern of the Ruffed Grouse’s rump is somewhat hard to analyze. It plays a small part in the side views, but has great prominence when the bird is seen from above. More than anything else, perhaps, it looks like a several yards distant patch of pine-needle-covered ground, peppered with small dead leaves, such as those of the Checkerberry (Gaultheria), or dappled with broken flecks of sunlight. 40 Fic. 33. Ruffed Grouse brooding. This picture admirably illustrates a phase of ground-matching by the Ruffed Grouse’s most beautiful and elaborate ‘obliterative’ picture-patterns. Photographed from life by George C. Embody. Fies. 34-35. Dead Ruffed Grouse laid on its side. Fig. 34, breast view; Fig, 35, back view because in wrong positions for the normal working of the obliterative shading, Photographed out of doors. ; both conspicuous Fic. 36, Two photographs of the same piece of a Great Horned Owl’s wing, super-imposed on a photograph of white pine woods, to show how closely the owl’s patterns reproduce such a forest-interior. It is to be remembered that aside from the nesting ordeal, the Ruffed Grouse’s greatest need of protection is in the autumn and winter, when many of the trees are leafless. Deep wood interiors are more or less brown, even in summer, and, above the ground, in winter likewise, so that a grouse’s colors are never really out of harmony with its environment; but it is in the two brown, leafless seasons between green summer and white winter that the average likeness between bird and landscape is the closest. During the snowy winter months the Ruffed Grouse becomes more largely arboreal, climbing about among the smaller branches of deciduous trees, with almost the agility’of a parrot or crossbill, picking buds—which are its principal food at this season. Forest vistas above the ground, with the intricately striate pattern of small, naked twigs, are therefore among its commonest winter backgrounds, and a large element of its pattern fits these scenes to perfection. Another bird which wears a highly developed forest-vista pattern is the American Great Horned Owl (Bubo virginianus). This owl sits nearly erect in deep woods, and its obliterative shading is proportionately slight. Horizontal-branch-barrings are the chief pattern of its underside, while its back and particularly its wing-coverts bear a beautifully suggestive picturing of variously extended vistas through the twigs and tree trunks. (See Fig. 36.) The white breast-mark looks like a sky vista, or some other large, light-colored detail of the woodland scene. It belongs among.contour-breaking ‘ruptive’ markings (see Chapter XIII, pp. 77-78) and among those which ‘let in’ the sky (chapter XXII, p. 149, etc.). The great European Eagle Owl (Bubo maximus) is almost the counter- part of B. virginianus in coloration, but somewhat more boldly and sparsely marked, in accordance with its less strictly sylvan life. The Great Gray or Lapp Owl (Scoptiaptex cinereum and S. cinereum lap- ponicum), an inhabitant of dense fir and spruce forests in the far north of both continents, wears a congested but little diversified pattern strongly suggestive of the dusky recesses of these northern woods. Most beautiful of all is the forest-picturing on the little Screech Owl (Megascops asio) of North America. 4I As is well known, there are two perfectly distinct color-phases of this owl, the red and the gray. It is in the gray plumage that the forest-pictures are most highly developed. Largely confined to this phase, also, is the curious defensive habit of sitting sharply erect, raising the ear tufts straight upward, closing the eyes to narrow diagonal slits, and drawing the feathers so close to the body that the usually fluffy bird is reduced to about one third its ordinary thickness. Of this interesting performance only one explanation, and one which long seemed sufficient, has been forthcoming. People have supposed that the owl practices protective mimicry, by assuming the aspect of a stick or stub. While it is not to be doubted that such a purpose is often served, in part, at least, yet the fact that the bird has counter shading—which even in the nearly erect position tends to ‘obliterate’ it, and to make it look unlike a stick —together with the very evident forest-vista character of its pattern, goes far toward proving that mimicry is not the only object of the trick. The grotesque contraction serves also to bring the background-pictures to their clearest and sharpest. The more tightly and closely a bird’s feathers are laid against its body, the clearer do all its markings become. The Ruffed Grouse has a like habit—so have bitterns and many other obliteratively colored birds—and in all these cases the action, whatever may be its other merits, is an essential adjunct of the obliterative equipment. Since, by every token, these birds are preéminently equipped for obliteration rather than for mimetic resemblance, it seems likely that the contracting-trick has greatest value as a factor of obliteration. On the other hand, it is undeniable that any such ‘contracted’ bird has moments of close mimetic likeness to a stick or stub. I shall return to this question in a later chapter. Judged by its markings, the European Woodcock (Scolo pace rusticola) would seem to belong most decidedly to the ‘forest-vista-picturing’ class, and such an opinion is largely vindicated by an examination of the bird’s habits. It lives to a great extent in upland forest coverts, where its beautiful and intricate wing- and side-pattern matches the vistas among trees and stumps, with glimpses of mottled forest ground, while its barred breast matches 42 Fi, 37. Stuffed Long-eared Owl in white pine woods. [Cf. the next figure. } Fig. 38. Stuffed Long-eared Owl in mixed woods. Tree-twig-and vista-pictur- Photograph. ing pattern (based, of course, on counter-shading.) Photograph, standing twigs and branches, and their shadows cast upon the ground. Many other beautiful examples could be given of this type of forest-pattern among birds. The next chapter will treat of grass patterns, separated from the other forms of near-background pattern which have already been considered because of their involving slightly different principles. 43 ‘CHAPTER VII BACKGROUND-PICTURING ON COUNTER-SHADED BIRDS, CONTINUED. GRASS AND HEATHER PATTERNS ON SPARROWS AND GALLINACEOUS BIRDS, ETC. HE grass-pattern birds, of various orders, constitute a pretty clearly- defined group in the obliteratively-patterned series. Generally speak- ing, there is much less diversity in the backgrounds of terrestrial birds which live in the open, than in those of forest birds, whether terrestrial or arboreal. The ingredients of a field bird’s background are comparatively few and simple, for the predominant vegetable forms of the open land are much less diverse in size, and somewhat less in shape, than those of the forest. Further- more, birds that are habitual dwellers on open ground—which, relatively to the littered forest floor, lacks minor variations of level—are rarely seen against anything but a very near background. Thus the possibility of their needing the distance-picturing type of obliterative pattern (as described at the be- ginning of Chapter VI) is largely eliminated. This comparative simplicity of marking requirements would lead us to expect great uniformity in the patterns of field birds; and investigation vindicates the supposition. Among the birds which are wholly confined to open ground, either bare or grass- grown, but which annually range over a wide territory, so that no one region’s peculiar ground-forms could advantageously be pictured on them, there exists a highly conventionalized ground-pattern of a fixed type, which is re- markably little varied through several genera and families, even orders. This type, always based on complete obliterative shading, is characterized by striations of light brown and black, coarsest on the back, and more or less varied by transverse bands and finer markings on the wings, scapular feathers, and other portions. Birds which wear it are Larks (Alaudide) 44 Fic. 39. Rocky Mountain White-tailed Ptarmigan in transitional plumage, against snow-brindled ground. Photographed from life by Edward R. Warren. Fic. 40. Rocky Mountain White-tailed Ptarmigan on her nest. Near- d-pi i spe “ course, ental oulerguveubadlag) [com 41, Uhape VLE) Sn as eae aE Ee ap ae a Photographed from life by Evan Lewis. Fre. 41. Rocky Mountain White-tailed Ptarmigan on her nest. a very remarkable photograph. Photographed from life by EB: Fic. 42. Rocky Mountain White-tailed Ptarmigan among pebbles, rocks and grasses. (Female and chick.) [Cf. Figs. 39-41. ] Photographed from life by Edward R. Warren. Fic, 48. Sage Grouse (Centrocercus urophasianus), a ‘grass-patterned’ and ‘shadow-marked’ bird. - aS adie Photographed from life by Edward R. Warren. (almost all the species except the Shore Lark and its races), Pipits (Anthus), certain European Warblers (Sylviine), various members of the Fringillide, and some of the shore and moorland haunting Limicole, as the Curlews (Numenius), and other Waders. Some of the more sedentary and local of the migratory field birds, as for example, the North American Yellow-winged Sparrow (Ammodramus savannarum passerinus) and the European Quail (Coturnix communis), have developed more highly specialized patterns of a very subtle nature,—patterns beautifully suggestive of the intricate small forms of earth and grasses. But it is among the actually sedentary (i. e., non-migra- tory) ground-birds of mountain moors and pastures, monotonous and little- varied regions, where the forms of vegetable growth which cover the summer ground are very limited in number, that the most simply specialized of back- ground-pictures may be found. Such birds are the Ptarmigans (Lagopus), already mentioned as preéminent among special-pattern birds. Living always in exposed situations, and being much sought by many rapacious birds and mammals, they are peculiarly dependent on protective coloration, at all seasons. Almost all the species (the sole exception, as far as I know, is the Scotch “Grouse,” Lagopus scoticus) turn white in winter, when their boreal or alpine haunts are covered deep in snow. In spring and fall the birds pass through a long intermediate stage, when they are curiously and ever-varyingly pied with white and brown or gray. The fact that they are thereby aided to escape detection on brown vernal ground mottled with patches of melting snow, or on ground half dimmed with scanty autumnal- snowfalls, might be considered nothing more than a coincidence, were it not for the extraordinary slowness of the two seasonal color-changes. There is perhaps no other bird which moults as gradually as the Ptarmigan, and this fact goes very far to strengthen the supposition that it has developed a pecu- liarly fluid and perfect system of perennial protective coloration. Figs. 8, 9, 10 and 39 show White-tailed Ptarmigans, of the Rocky Mountains, in winter and transitional plumages. The photographs were taken from wild birds in their native haunts. Supremely beautiful and potent is the grass- 45 pattern of this same species in summer plumage. See Figs. 4o and 41, the second of which is one of the most remarkable photographs ever taken of obliteratively colored birds in nature. Both photographs are of hen birds on their nests. We have never been in the haunts of this ptarmigan, and therefore cannot speak from personal experience as to the prevalence on its breeding grounds of the strong, wiry grasses which form the brooding bird’s background in these pictures, as well as in others not published here. But the late Mr. Evan Lewis, of Idaho Springs, Col., who took the photo- graphs, wrote us confirming our foregone conclusions as to the abundance and general distribution of grasses of this type in the summer home of the Southern White-tailed Ptarmigan. Indeed, an examination of the photographs leaves one no room for doubt upon this score. So consummate a resemblance could not be merely casual. The principal feature of the pattern made by grasses over ground is a more or less intricate lace-work of crisscrossing, light-colored, linear forms, some straight, some curled and twisted, relieving with varying intensity against dark. This pattern has the important attribute of simplicity, and is worn not only by many birds and some frogs, but even by certain moths, which rest on the ground during the daytime.* In the case of the ptarmigan, it is achieved by light-brown marginal bands, with a few small internal spots, on the dark feathers of the upper parts; the predominance of light and dark being grad- ually reversed as the lower breast is approached. The belly is entirely white, as are the quill feathers of the wings and tail. The white of both wings and tail, however, is entirely hidden by grass-marked ‘coverts’ when the bird is brooding. In addition to the phases already described, this bird has an early autumn plumage of softer and grayer colors, withott white blotches, which doubtless fits it to live more among the rocks, and less among the grasses. The colors of ptarmigans, in fact, are almost interminably various, from month to month. It seems almost as if they underwent a perpetual moult. The grass-pattern plumage of the nesting season, however, must be very constant. * These will be considered later. 46 Photographed from nature by C, Reid, W: duced hy courtesy of “Country Life,” haw. Repro- London, Fic. 46. Young Western Meadowlarks in their ground nest. ‘Grass- : pattern’ birds, Photographed from life by Cherry and Richard Kearton Photographed from life by Finley & Bohiman. » Fic, 45. Nesting Scotch Grouse (Ptarmigan). Fig. 47, Nesting female Eider Duck. Ground-picturing pattern, based on counter-shading. Photographed from nature. By courtesy of ‘Country Life,’’ London. Fig. 48. Young Short-eared Owls, in their nest on the ground. Photographed from life by Cherry and Richard Kearton. Another kind of Ptarmigan of which we have secured good photographs from life is the Lagopus scoticus, the so-called “Grouse” of the British Isl- ands (Figs. 44 and 45). This is preéminently a bird of the heather, and it is gratifying to see how subtilely and significantly its markings differ from those of the American species which nest among grasses. It is completely covered with wonderful heather-pictures, recognizable as such even when the bird is examined away from its true environment. The more complex forms of the crowded and delicately branching heather plants, with their twigs and leaves and blossoms, are copied by various modifications of the bird’s pattern. Rel- atively to that of the grass-ptarmigans this pattern is characterized by the multiplicity of its small, light-colored forms, which are also greatly more var- ied both in shade and color, to simulate the complexer surface-pattern and in- terior-vistas of the heather plants, with their variously illuminated details. (Technically, the difference consists chiefly in the wider and wavier marginal bands, and in a copious speckling of darker brown upon the fuscous ground- color within these bands.) The bird shown in Fig. 40 was unfavorably ar- ranged as to obliterative shading, but certain features of its obliterative pat- tern are shown off to consummate advantage. The pattern of its rump and back is scarcely recognizably different from that of the heather around its tail and nearer wing, while the picturing of heather-bells by its breast-pattern is astonishingly close. The obliterative shading of this species is so extremely slight that we must infer that it is wont to lie very deeply settled into the heath, and often more or less overarched by it, so that the preponderance of direct top-light is reduced to a minimum. The dark area on the actual belly, which this species shares with several other gallinaceous birds of different genera, has little or no bearing on the case, as it is invariably out of sight when the bird is ‘lying close.” (The use of such markings will be discussed in a later chapter.) The ptarmigans which resort often to bare ground and rock, as also the arboreal Galline, lack this ‘squatting-patch,’ and light bellies are essential factors of their concealment. Even some of the rock-haunting ptarmigans, however, have a somewhat weak obliterative shading, and this is 47 in keeping with the fact that on mountains there is an unusually great pro- portion of szde-light. Still another notable type of pattern worn by birds of grass-lands and the open plains, is composed of a system of bold transverse bars of black and brown, or kindred colors. This exists, for instance, on some of the Tinamous (Tinamide) of South America, and, in a very high state of development, on the European Great Bustard (Otis tarda). Its effect is much the same as that of the other grass-patterns, but it seems in most cases to be a cruder and less highly finished form. The pattern of the Little Bustard (Otis tetrax) is somewhat of this type, though refined toward elaborate picturing, and is very beautiful and effective. The female especially is one of the most exquisitely counter-shaded and picture-patterned of birds. 48 Vic. 49, Yellow Wagtail amid grasses. Photographed from life by Cherry and Richard Kearton. < ty ass fw Send ‘a , ~= bo — SN SAS Ma A Fic. 50, Male Bob-white (Colinus virginianus) on its nest. Highly-developed pic- ture-pattern, based on full obliterative shading. Photographed from life by Maunsell S. Crosby. Courtesy of ‘* Bird Lore.” FG. 51, Male Golden Plover with chick, in grass. Obliterative shading and grass-picturing-pattern, etc. This bird is also a heather-haunter, [See p. 53, Chap. Photographed from life by Cherry and Richard Kearton. Fic. 52. Nesting ‘‘ Upland Plover” (Bartram’s Sane; a ‘grass-pattern’ bird. Photographed from life by J. E. Seebold CHAPTER VIII BACKGROUND-PICTURING ON OBLITERATIVELY-SHADED BIRDS, CONTINUED. THE VARIOUS PATTERNS OF SCANSORIAL BIRDS CANSORIAL birds are for the most part tree-trunk climbers. They are the Woodpeckers (Picide), the Wrynecks (Jyngide), the Nuthatches (Sitting), the small Northern Creepers (Certhiwd@), the Wood Creepers (Dendrocolaptide), and a few other forms. Most of these birds—notably both families of Creepers—spend almost all their time in a nearly vertical position, clinging to the bark of tree trunks with claws and tail, or claws alone. The Nuthatches climb head-first down- ward as well as upward, the others seldom or never do. In spite of the erect climbing-position in which they spend their lives, these birds are almost without exception dark on the back and light on the breast and belly, and many of them have a delicate, complete gradation from the dark side to the light. The underside may be pure white, as in the case of many woodpeckers, or brown, barely lighter than that of the back, as in some of the Dendrocolaptide. But in the whole catalogue of species we know of none which is not thus counter-shaded, more or less pronouncedly. But how, then, the reader may ask, does this regulation counter shading con- ‘ form with these birds’ vertical habit of life? ‘The answer is plain. The solid, leaf-crowned trunks up which they climb cut off the light from their breasts, and almost all that reaches them strikes laterally or diagonally on their backs. It is the same scheme over again, but carried out on a vertical instead of a horizontal plane. The patterns of these climbing birds are extremely various, ranging from none at all, as in some of the Wood Creepers, etc., to exquisitely elaborate 49 bark- and vista-pictures much like those worn by goatsuckers, as in the Wry- necks. The unmarked Wood Creepers—whose counter shading also, in some cases, is very slight—frequent brown stumps and trunks, in very heavily shaded forests. Other members of the same family, with closely similar habits, have streaks and a more pronounced counter shading. Bark picturing plays a very large part in the disguises of several classes of animals, probably reaching its consummation among moths and _ butter- flies, as we shall see later on. Cruder * forms of it among birds are represented by the streakings and mottlings of the Creepers (Certhiide and Dendrocolap- tide), by the close transverse barrings of the backs of certain Woodpeckers, and the bold spottings and stripings of other members of that family. All these devices, especially the barrings and stripings, are, at a little distance, effective bark-pictures. The pattern of the small Northern Creepers (Cer- thia) is perhaps too highly developed to be rightly classed among these others, and should be treated rather as a connecting link between them and the ex- quisite picture-pattern of the Common Wryneck (Jynx torquilla). This last is one of the most wonderfully equipped and beautiful among obliteratively- colored birds, and is evidently one which, like the goatsuckers, often stays stock-still in time of danger, allowing its enemy to make an exceedingly near approach before it moves. Its buff-colored breast and rufous primaries bear the same form of transverse dusky barring as is worn by so many of the larger forest birds, while its back is mottled and lined and peppered with several tones of gray and dusky, in minute picturing of bark seen at close range. In back view the bird would usually be seen against the very tree to which it is clinging, in side view usually against branches and trunks, and more distant forest vistas. And behold! its markings are developed correspondingly. * Whenever we call a coloration cruder, or less developed, without trying to state the function of this so-called crudeness, it must be understood that such a function surely exists. It is, evidently, only the need of this coloration to represent different backgrounds, that can limit its development toward any particular one.—A. H. T. 50 On its sides (breast, cheeks, flanks, wing-coverts, etc.) are the delicate twig- and vista-pictures, and on its back the near-bark marblings. The beautifully banded tail serves well in either view. Indeed, the Wryneck’s oblitera- tive coloration involves the same principles and sorts of background pictur- ing as does that of the Ruffed Grouse and other forest birds described in Chapter VI. We have now glanced at most of the main types of coloration among tree- trunk-climbing birds. In a later chapter I shall recur briefly to the subject of the bolder markings of woodpeckers and nuthatches. 51 CHAPTER Ix BACKGROUND-PICTURING ON OBLITERATIVELY-SHADED BIRDS, CONTINUED. BEACH-SAND- AND PEBBLE-PATTERNS OF THE SHORE BIRDS (Limicole). GENERALIZATIONS AND COMPARISONS BLITERATIVE shading, pure and simple, is the rule among the Shore Birds (Limicole). ‘There are a few somewhat anomalous cases— e. g., the summer costumes of the Golden and Black-bellied Plovers, and the Dusky Redshank (Totanus fuliginosus), which we will consider later on; but for the most part the birds of this order show great simplicity and uniform- ity in their obliterative coloration. The markings of many of the species which inhabit pebbly shores and wave-marked, sandy beaches are much like those of the grass-pattern birds described in Chapter VII, but even simpler. Littoral flats, whether of sand or shingle, are for the most part characterized by great monotony and blankness, being governed by few and simple laws, and almost wholly wanting the complex element of vegetable life, with which we have had mainly to deal in the foregoing chapters. Since the birds that inhabit these beaches are almost all great wanderers, making long semi- annual migrations, one would expect to find their patterns not only simple but highly generalized, and varying little among the species. A comparison of the more strictly littoral among the smaller shore birds will show that this is actually the case. There are, indeed, two quite distinct types among them, but almost all the species belong to one or the other of these two. The one includes those which are largely destitute of picture-pattern—e. g., the smaller plovers (4¢gialitis), the other those which are well provided with such pat- terns, of a regular and simple kind—e. g., many of the sandpipers (Tringa, etc.). The patterns of sand and shingle and tidal mud flat are apt to be so slight that a bird can be well concealed on such ground by counter shading 52 and color alone, as in the case of the plovers; but Nature has given many of her beach-birds a picturing of the faint patterns. Wave-lines left at low tide on bright sandy beaches, narrowed in perspective, the lines of small lapping rollers over shallows, strips of stranded driftweed, shells, heaped or scattered, straggling blades of beach grass—these, varied by the even speck- ling of broad pebble-beds, are the chief features of the ground-scene on blank shores where sandpipers and plovers troop and feed. So do we find the bird’s pattern, wherever it occurs, delicate and linear and wavy, with few in- tricacies, and a persistent tendency toward lengthwise striping and crescentic spots. The effect may be produced by light markings on dark, by dark on light, or by both; but the patterns are all much alike in general character. Marginal bands play the chief part in all these simpler picture-patterns, and this is even truer of the beach than of the grass type. ‘These two phases of pat- tern are well connected by intermediate forms, worn by some of the Limicole that live more or less largely in the fields or moorlands. Such are the Cur- lews (Numenius), already mentioned among grass-pattern birds, the Thick- knees (Gidicnemide), and the North American Bartram’s Sandpiper (Bar- tramia longicauda), which has, indeed, one of the most highly specialized of ‘srass-patterns.’ (See Fig. 52 and Chapter VII.) Again, among the true plovers we find an outcropping of the heather pat- tern, in conformity with the heath- and tundra-haunting habits of the birds that wear it. Such are the several races of the Golden Plover (Charadrius), which breeds in the far north of both continents, and, to some extent, its rel- ative the Black-bellied Plover (Squatarola), of like distribution. Good examples of the pure beach type are the winter costumes of the Knot (Tringa canutus), the Sanderling (Calidris arenaria), the Semipalmated Sandpiper (Ereunetes), and the Stints (Tringa minuta, T. temminckii, etc.). Most of the birds of this family wear a more grass-like pattern in summer than in winter, a fact which is in perfect keeping with their habits, for during the nesting season they tend to forsake the beaches and to live among the weeds and grasses. Some, like the Pectoral Sandpiper (Tringa 53 maculata), stick to grassy swamps throughout the year, and their pattern tells the tale. The true snipes (Gallinago), already treated of in another division because of the rich intricacy of their markings, have a pronounced element of grass- pattern, and both in markings and in habits form a connecting link between the grass birds and the woodland bog birds, typified by the American Wood- cock (Philohela minor). In like manner the sand- and pebble-type of pattern is modified toward rock-surface picturing,—as in the winter plumage of the Purple Sandpiper (Tringa maritima), one of the most highly ‘obliterated’ of birds, and a sandpiper peculiar in its restriction (at least in winter) to rock- baund ocean shores. In the same way the pattern of the terrestrial goat- suckers, described in Chapter V, is modified toward rock-picturing in the plumage of that rock-haunting member of the family, the Nighthawk (Chor- deiles). From all this it appears that the types and forms of picture-pattern worn by birds, though easily separable into classes when grouped about the several conspicuously pure examples, are yet in the whole range of species closely blended and intermingled, more or less irrespective of the structural affinities of the birds which wear them, but nearly always in obvious conformity with their specific habits. It would seem, indeed, as if Nature in its entirety should represent one great, blended scale, shaded throughout insensibly like the colors in the spectrum, and as if the breaks and interruptions which form the bases of zodlogical classification and separate grouping were in a sense imperfections. In the world of birds, for instance, though the breaks and anomalies are numerous, there are yet many evidences of the past existence of a smooth gradation connecting types now sundered.* On the other hand, it is also true that gaps in the fundamental affinities of birds are often super- ficially bridged over by similar habits, probably of more recent acquirement, and these are usually accompanied by corresponding outward resemblances, * See Robert Ridgeway, in the preface to his ‘‘Birds of North America,” whence much of this thought is taken. 54 particularly those of plumage. Thus we discover, even in the study of the disguising-coloration of the birds of to-day, a wonderful intermingling and gradation between the types, which makes it hard to consider them separately. But division and classification are essential to analysis, and by taking a prom- inent type-center as the theme of a chapter, we can better examine both its differences and its affinities. Those we have already glanced at are perhaps the most representative and notable of the many types of picture-pattern worn by obliteratively-shaded land and beach birds. It remains for us to consider the markings of rails and other swamp birds, of obliteratively-shaded ducks, etc., and also the several obliterative uses more or less independent of counter shading which are served by spots and patterns in birds’ costumes. 55 CHAPTER X BACKGROUND-PICTURING ON OBLITERATIVELY SHADED BIRDS, CONTINUED. REED PATTERNS AND OTHER MARKINGS OF BITTERNS. THE COLORATION OF HERONS IN GENERAL NE more pronounced. modification of the ‘dead-grass’ type of picture- pattern must be considered. This is the picturing in a near view of straight, erect reeds, which exists on the necks and heads of several herons, notably the American Bittern (Botaurus lentiginosus), which shall serve as our example. Many herons are wont to stand motionless, with neck and head extended and erect, and in the bitterns this habit reaches its climax. The American Bittern will stand for an hour at a time ina swampy meadow, with scarcely a movement of its erected, straight and stick-like neck and head, terminating in the long, sharp bill, which points directly upward. When, as is pretty frequently the case, the neck and head in this position project above the reeds or grasses, they look, in certain lights, and from a sufficient distance, like a pointed stick or stub. This fact has been commented on by many writers, all of whom, it seems, have thought it a sufficient explanation of the Bittern’s curious trick. Though we admit that the stick-aspect is sometimes most pronounced, and must therefore have a bearing on the significance of the habit, we are convinced that this has another function of far greater im- portance, namely, the display in correct position, and with the clearness gained by depressed feathers, of the reed-stripes on the upper neck, which extend sharp and unbroken over the head, and are even continued on the bill. The following extract from my journal, recording my first recognition of the high obliterative efficacy of these stripes, contains some details which make it worth quoting: ‘But if this [stick-mimicry] were the explanation, what would be the function of the finely developed, sharply contrasted stripes 56 of light and dark, running lengthwise of the head and neck, and best shown when the bird is standing erect in the attitude alluded to, with feathers closely depressed? It is plain that these markings cannot help the ‘stick’ aspect, but must rather injure it, inasmuch as a single stick or stem would be of uni- form coloration, or at most mottled, rather than marked with sharp and strong longitudinal stripes. The true explanation flashed into my mind to-day as I was watching a standing Bittern at a distance of about ten feet. The light stripes on the bill were repeated and continued by the light stripes on the sides of the head and neck, and together they imitated very closely the look of separate, bright reed-stems; while the dark stripes pictured reeds in shadow, or the shadowed interstices between the stems. The truth of this explanation must be apparent to any one with an eye for such things, who watches at close range a Bittern standing motionless among reeds.” To be sure, Bit- terns’ heads and necks are often seen projecting stick-like over the tops of meadow-grasses and half-grown reeds, but who knows how many times Bit- terns’ heads in this same attitude among the reeds escape all notice, by virtue of their beautiful rush-pattern? It may very well be that the projecting-stick aspect is, relatively at least, exceptional and unimportant. My own obser- vations of Bitterns in their haunts all tend toward such a conclusion. Reed-like patterns occur also, though in less marked development, on the necks of some of the true herons, as for instance the Purple Heron (Ardea purpurea) of southern Europe. The beautiful European Bittern (Botaurus stellaris) has kindred markings with a strong admixture of richly brindled grass-pattern—a pattern at once bold and subtile, whose obliterative effect in the bird’s normal environment must be consummate. So also with the South American Botaurus pinnatus. The Least Bitterns (Ardetta), of Eu- rope and America, have also delicately reed-marked heads and necks. There are doubtless many other examples which might be cited, but these are all that occur to me. A modification of the type of grass-pattern described at the end of Chap- ter VII occurs on the South American Tiger Herons (Tigrisoma), with their Sf minute transverse barrings or grizzlings of olive and black. Like the bit- terns, they are inhabitants of reed and grass swamps. All these birds have obliteratively-shaded bodies, and—in the slight degree consistent with the characteristic nearly erect position of these parts—obliteratively-shaded necks and heads. The coloration of herons in. general is exceptionally various, including as it does such extremes as the richly mottled brown of bitterns and the immacu- late snow-white of egrets and some others,—the supposed ‘‘conspicuous”’ species. (In a later chapter we shall show that these egrets too, and all such birds, are obliteratively colored.) Herons walk and rest, very commonly, almost erect, and their obliterative shading is often not very pronounced, though present, and evenly developed, in the majority of species. The colors of shallow and shaded water—subdued blues and greens and purples, some- times enriched and subtilized by iridescence,* predominate in their plumage, and they usually have bright reed- and water-colors on their naked legs and bills.| Their markings are various, sometimes pronounced and clear, some- times obscure, or even lacking altogether, but almost always perfectly and obviously consistent with the water-picturing suggested by their general color- tones. It is significant, too, that in spite of the much diversity in herons’ colors, there are no brown and elaborately-patterned species except some of those that live in grassy marshes and dense reed-swamps, where they skulk almost like rails—the first subjects of our next chapter. * See p. 92, Chapter XVI. { See Chapter XV. Fic. 53,.- «tmerican Bittern on its nest, ‘obliterated’ by picturc- Fie. 54, Nesting Virginia Rail, ‘ubliterated’ by counter-shading pattern based on counter-shading. (The ‘reed-stripes’ mentioned in and background-picturing pattern. the text are here not in full operation.’ Photographed from life by E. |. Tabor, Photographed from life by E. G. Tabor. Fie. 55. Wilson’s Tern on its nest. (Counter-shading and) ‘ruptive’ pattern. Photographed from life by Francis H. Herrick. Courtesy also of G. P. Putnam's Sons. PLATE Il AORN & CO, BALTIMORE . EXPLANATION OF PLATE III MALE WOOD DUCK ON SHALLOW WATER. Sketch’ by Richard S. Meryman MALE Woon DUCK IN A FOREST POOL. Painted by Abbott’H. Thayer, assisted by Richard 5. Merman _ Qhe bird wag painted from a stuffed specimen, and the | background copied, color-note for color-note, from the bird " himself. Cf. the backgrounds of the: Rattlesnake, Figure 123; the Bird-of-Paradise, Plate VI; and the Flamingoes. CHAPTER XI BACKGROUND-PICTURING ON OBLITERATIVELY SHADED BIRDS, CONTINUED. WATER MARKINGS AND COLORS HE duskiness of obliterative shading on such birds as rails, gallinules and coots, is in keeping with their habit of skulking under deep marshy cover, closely shaded from the direct top light, and often, momentarily, lighted more from the side than from above. A true obliterative shading exists, how- ever, on almost all the species. Two or three main types of coloration prevail among them, but there is little variation beyond these types, and only such as is consistent with ‘obliteration.’ The colors of water, much like those worn by herons, predominate among the more aquatic species, the coots and gallinules. Olive, green, blue, purple, slate-gray, dusky—these are charac- teristic gallinule colors, and likewise the colors of water. A few of the birds that wear them are scantily or not at all counter-shaded. The Purple Galli- nule (Jonornis martinica) for instance, with its bright but softly-blended water tones, is as dark beneath as above, though there is a counter shading from the middle of its back to the lower edge of its folded wing. It lives for the most part over deeply and diversely shaded pools, and amidst the big, glisten- ing leaves of water plants, and its peculiar coloration does certainly achieve adequate ‘obliteration.’ (This will be explained more fully in a later chap- ter.) It is noteworthy, however, that in almost all cases where the adult plumage of one of these swamp-haunting species lacks obliterative shading, that of the young possesses it in full. This is true not only of the Purple Gal- linule, but in a remarkable degree of some of the jacanas, as the common Jacana jacana of South America. These birds live in tame and noisy flocks oo on shallow lakes, lagoons, and miry marshes, and, unlike rails and gallinules, they do not skulk and stick to cover, but stay almost always in the open reaches, where they are exposed to the view of predatory birds and beasts. The adults are black underneath and rich red-brown above, with pea-green wings. As birds go, they are apt to be conspicuous, although not always easily discerni- ble amidst the multitudinous sharp lights and shadows of the labyrinths of lily pads over which they often walk. Watching a flock of jacanas feeding un- der the noonday sun, one sees from a little distance mainly the black-breasted adults—of the more daintily-colored, white-breasted young there seem to be only two or three in the whole flock of a score or more. But when the horizontal sun-rays of late afternoon or early morning stream across the marsh, behold a revelation! The young, concealed till now by their counter shading, show up in quantities, outnumbering the adults almost two to one. This is a most beautiful and convincing exhibition of the power of obliterative shading, and one which must leave a lasting impression on the mind of every observant person who sees it. But it suggests also an interesting question—so interesting that, though it leads us into the tabooed region of hypothesis, we must be permitted to discuss it briefly. Why are the adult jacanas deprived of the counter shad- ing which served their youth so well? Adult gallinules also, it is true, lack counter shading, but they are always alert to skip into deep cover at a moment’s notice, whereas the jacanas, as I have said, live in flocks, conspicuously ex- posed, in the open tracts of lagoons and marshes, and rarely or never take to cover unless wounded. Is it not highly probable that the strong spurs on their wings have something to do with all this? May it not be that the young, weak-spurred and inexperienced, need concealment in situations where the adults, with their hard, sharp thorns, are well able to protect them- selves? * Undoubtedly, the dark-hued parents must often serve to distract the attention of predatory creatures from their obliteratively-colored but defenseless young. Certain it is that these spurs are not, like those of cocks * There must, of course, be situations where the adults are as obliteratively colored as the young. — A. H. T. 60 and pheasants, for battles among the birds themselves, for they are worn equally by the small males and the much larger females. Evidently, then, they are for defense against outside enemies, such as alligators, iguanas, tor- toises, and predatory birds and mammals. That they are very effective weapons seems to be attested by the birds’ abundance, noisiness, and tame and nonchalant manner. The colors of rails differ from those of gallinules and coots (and differ even among the several species), exactly as do their habits. They are more terrestrial, and their general color-scheme accordingly is browner. The backs of many species bear a subdued and dusky striate pattern of the ‘grass’ type—richer and brighter on the more terrestrial kinds, and vice versa. (See Fig. 52.) Some are slate-gray underneath, others pale rufous, or grayish white; but almost all have a complete counter shading, with a light culmi- nation on the vent and belly. Some, like the Yellow Rail (Porzana novebor- acensis), have a background-picturing pattern of delicate, grasslike, pale- brown barrings. But it is the patterns for which the birds of this family are peculiar that we have here to consider. These are the characteristic bar- rings on the flank feathers (in Rallus) and the system of pure-white specklings and slender stripings on the dark-colored upper sides (in Porzana)—mark- ings which, although not, indeed, strictly limited to the rails, yet reach an unusually high degree of development and significance among them. Water pictures of some kind they plainly are; and it is not difficult to go further and perceive what details and aspects of reed-swamp surfaces they most resemble. The white punctations picture broken glints of sky-shine on the dusky water, seen beyond and through the dim vegetation-pattern, rendered by the darker markings of the birds’ backs. The barred flank-pattern pictures glimmering water intersected by bold shadows from the reeds—or by intervening shaded reeds themselves. That crane-like relative of the rails, the Courlan (Ara- mus), the ground-color of whose costume is the deep, dull brown of heavily shaded, muddy water, has likewise a water-glint pattern of pure-white spots on its head and neck. This I have seen performing admirably its ‘obliter- 61 ative’ function, on a wounded bird in hiding. The white specklings of some of the Wood Sandpipers (Totanus) and various other water-haunting birds (e. g., the loons, Gavia) belong more or less strictly to this same class of ‘water-glint’ pictures. So, too, the rails’ barred flank-pattern has affinities with the markings of other water birds, such as certain ducks. On them, however, it is developed into ripple-picturing. The beautifully contrasted black-and-white bars on the flanks of the Wood Duck (Aix sponsa) are ripple pictures, and as potent, in their place, as the most elaborate markings of land birds—while they are even more remarkable in that they depict motion. These markings of the Wood Duck cross the flank feathers transversely, yet when the feathers are laid in their natural upcurled position, overlapping the wing, their pattern forms one brilliantly accentuated horizontal stripe. ‘Thus, though made by flank feathers, this marking is merely another form of the longitudinally striate scapular- or wing-pattern worn by so many other ducks, and serves ex- actly the same purpose. More than two thirds of the American and European ducks have one form or another of this marking, and on many of them it is most pronounced. It corresponds to the ‘secant’ stripe of certain land birds, but is often more elaborate (consisting sometimes of several tiers of stripes), and has an even more definite ‘obliterative’ use. It may be seen in its perfection on the Wood Duck, already mentioned, on the Pintail (Dafila acuta), the Green-winged Teals (Vettion), the Garganey (Querquedula circia), the Widgeons (Mareca), the Golden-eyes (Clangula clangula, etc.), the Long- tailed Duck or Old Squaw (Harelda hyemalis), the Steller’s Eider (Eniconetta stellert), the Hooded Merganser (Lophodytes cucullatus), and the Red-breasted Merganser (Merganser serrator). Its position varies from the flank feathers, as in Aix, to the secondary wing feathers, as in Merganser, the tertiaries, as in Mareca, and the scapulars, the feathers of the sides of the back, as in Dafila, Nettion, Harelda—in fact, the great majority of species. Its character and effect, however, are nearly the same in these several positions. A swimming duck leaves a spreading, wedge-shaped trail of curling ripples, very noticeable 62 in quiet water, while shorter ripple-lines also roll out in front of the bird’s breast. Seen in profile against the water, the duck’s body hides a portion of the perturbed and wavy surface extending from its further side, and tends to ‘relieve’ noticeably against it. But this ‘relieving’ Nature combats with the bright ‘secant’ stripes, which, by their beautiful likeness to rolling wavelets, with shine and shadow, go far toward ‘merging’ the duck’s otherwise well ‘obliterated’ body into the troubled water beyond it. The peculiar ripples, real and pictured, may still suggest a swimming bird, but just where the bird really is—where alone the eye is led to expect it—there seems to be nothing. but water,—for the wave-lines extend across its dim body. This is a very important factor of disguise among ducks, particularly those that inhabit quiet inland water. Among deep-sea ducks it is less common. But the same system, sometimes elaborated, and including sharp transverse markings, occurs on a few of the oceanic species. Another peculiar form of pattern, common to even more kinds of duck, is a fine, black or gray vermiculation of the back or sides, as on Teals, Scaups, Canvasbacks, Wood Ducks, and many others. Indeed, this pattern is al- most universal among ducks, and there are comparatively few (these mostly deep-sea kinds) that lack all trace of it. It serves as a generalized picturing of shimmering water, fretted with broken shore-reflections, or ruffled into tiny ripples by light breezes. Considering its prevalence among highly ‘obliter- ated’ water birds, one can hardly doubt that such is its main function. On some species which frequent shallow inland waters, like the Wood Duck and the Hooded Merganser, the dusky vermiculation is exceedingly close and delicate, over a ground-color of golden brown. In these cases it seems to picture the sandy bottom seen through shallow water at the stream’s or pond’s edge. As a rule, the vermiculated pattern occurs on the sides, and its minuteness therefore fits it to match its wearer’s more or less distant watery background, with its ripples and reflections dwarfed and refined by perspective. The much coarser wavy markings of some geese, though they serve also the purpose of ground-. and grass-picturing, in conformity 63 with the birds’ half-terrestrial habits, have yet much in common with ducks’ grizzled water-patterns; and the two types are connected by intermediate forms, e. g., the breast-pattern of the Ruddy Duck (Erismatura jamaicensis). Ducks have still another very characteristic obliterative marking, the bright-colored ‘‘speculum”—a broad band, often of metallic green, blue, and purple, crossing the middles of the secondary wing feathers. This marking can but poorly serve the purpose (commonly supposed to be the main function of all such marks) of display in flight, for the color is confined to the tops of the outer webs of the wing feathers, and so only makes a continuous band when the wing is folded. Its obliterative use, on the other hand, is most pronounced. It gives the effect of a ‘window’ through the body of the bird to the water or vegetation beyond.*+ This speculum is almost always of some characteristic water tint—blue, green, or gray. Often it is highly iridescent, which makes it additionally effective (as will be explained at length in a later chapter). On some species, such as the Scaups (Aythya marila, etc.), it is white. But even pure white serves the same ‘obliterative’ purpose, picturing a sky-reflection on the background-water. All these factors in the disguising costumes of ducks are usually parts of an ‘obliterative’ scheme based on full obliterative shading. Very few ducks lack this counter shading, and most of them have it in full development, particularly the females, and the males in post-nuptial summer plumage. The singular change to a dull-colored summer dress, like that of the females, which most male ducks yearly undergo, is coincident with their loss, and lack, for many weeks, of all flight-feathers. Discussing this phenomenon, an eminent English ornithologist remarks:{ ‘‘Most of these birds (Anatide) * Much the same purpose is served by the beautiful metallic spots or patches of water-color (deep blue, green, and violet) on other parts of the body, worn by many sea ducks, notably Steller’s Eider. This bird has indeed a supremely beautiful pattern of ice and water pictures. + Little used while the duck is swimming, but greatly when he walks about on the adjacent shore, in far greater danger from his enemies. These speculums prove, also, to have a wonderful power to obliterate their wearers against the sky, to the eyes of creeping enemies that flush them.—A. H. T. t See the ‘‘Encyclopedia Britannica,” vol. iii, p. 776 (of the R. S. Peale Reprint). 64 shed their quill-feathers all at once, and become absolutely incapable of flight for a season, during which they generally seek the shelter of thick aquatic herbage, and it is further to be particularly remarked that the males of two sections of the family (Anatine and Fuliguline) at the same time lose the brilliantly-colored plumage which commonly distinguishes them, and ‘go into eclipse,’ as Waterton happily said, putting on for several weeks a dingy garb much resembling that of the other sex, to resume their gay attire only when, their new quills being grown, it can be safely flaunted in the open air.” Here are the facts, but without the true conclusion which’ should be drawn from ttem—the conclusion which is unavoidable in the light of a wider knowledge of protective coloration. This is, that the male duck’s assumption of dull plumage is an adaptation to his new environment, rather than to his altered bodily condition. We skulks among the reeds because he is flightless, and he assumes a mottled grass- and reed-like pattern to fit him to this new environment; but the mottled pattern is no more protective, i. e., ‘obliterative,’ than the pied waéer-pattern of his full plumage, worn when he forsakes the shelter of the shore. Male Eiders (Somateria) keep out at sea while their brown, mottled females (see Fig. 47) hatch the eggs (sometimes a long way from the water) and tend the young, and though the males (as well as the females) are flightless for a while, they retain their full plumage almost un- altered. This full plumage has no obliterative shade-gradation, but con- sists of a bold ‘ruptive’ pattern of ice- and water-colors—as will be further explained in a later chapter. A few male sea-ducks, such as the more or less wholly black Scoters (Oidemia), are conspicuous at sea, though well equipped for inconspicuousness against dark cliffs. Their females, which have to brood the eggs on shore, are more or less adequately ‘obliterated’ by counter shading, color, and markings. There are, however, some species of swimming birds in which even the females are quite without counter shading. Such are swans,* for instance, and cormorants—though cormo- rants are otherwise equipped for concealment on shore by rock-like * See p. 154, Chapter XXII. 65 markings, and by iridescence, which must often admirably mask them under water also. The foregoing sketch of ducks’ disguising coloration touches on most of the main general facts. But the reader must now be subjected to a de- tailed description of the obliterative equipment of one particular species, the Wood Duck, the male of which is almost unsurpassed among birds in the combined boldness and intense subtlety of its disguising coloration. (See Plates IIJ and IV.) The general scheme of this beautiful bird’s ‘disguise- ment’ includes a full and potent obliterative shading, from blue-black on the back and tail to pure white on the entire underside, shading through sand-color on the flanks and through chestnut, mixed with white, on the breast. The throat also is white, ending abruptly against deep velvet bronze and purple on the cheeks. Founded on this, underlying obliterative shading, which cancels the bird’s visible solidity, and prepares him for ‘background matching,’ there is a bright and beautiful system of water-pictures, of many kinds, bolder and more vivid than those of any other bird we know (with the possible exception of Steller’s Eider). For the most part, these pictures are of shore- and sky-reflections, subtilely and richly intermingled, and comprising a great variety of effects. The colors are mainly deep and soft, though rich, and liquidly alive with sober iridescence. Their range (excluding the sandy flanks) is from chestnut red glossed over with purple, through all degrees of blue to golden green;—perfect woodland water colors, all of them. Olive- ash color occurs on the lesser wing-coverts and primary quills, and this, the tint of lusterless still water near the shore, between reflections, is a connecting link between the brighter water-pictures and the sand-colored sides. The scapulars, which meet over the back, are somber blackish, with a glimmering of blue; water deeply shaded, showing a dark bottom, or reflecting something dusky. The “speculum” and some of the greater wing-coverts, together forming a patch which intervenes between the back and flanks, and, longi- tudinally, between the two areas of ashy olive, are bright and lustrous blue, ranging from almost purple to deep robin’s-egg, and including also, on a single 66 feather of the speculum, a blended patch of copper red, sometimes combined with greenish bronze and purple. All these feathers are iridescent, but their changeableness is mainly from dusky to bright, rather than from one bright tint to another. They render beautifully a portion of the surface of the dim translucent water where there is a somewhat vague reflection of the sky or of plants above. Forward, this patch is blended softly into the ashen olive of ‘the wing-coverts; while the speculum is bordered outwardly with a band of white—like a sharp streak of the clearest sky-reflection on the elsewhere dim, semi-transparent water. So, in lesser degree, with the grayish-white longi- tudinal stripe formed by the outer veins of the folded primaries, above sharply bordered with dark blue (the outer veins and a narrow stripe next the shaft on the inner veins of the primaries), and forward blended smoothly into the ashen-olive patch at the bases of the primaries. This combination of softly blended with clean-cut, sharp-edged markings is what gives the water-picturing its peculiar magic, for it represents the two main characteristic elements in the aspect of quiet water, namely, vistas through the surface into the liquid depths, and reflections, on the surjace, of things above. As in the duck’s costume, so in the water which it pictures, these two elements are now sharply differentiated, and now intimately blended. Most potent of all, perhaps, are the pictures of reflection on the Wood Duck’s richly crested, green and purple head, with its clean-cut stripes and bars of snowy white. These white marks picture bright and sharp reflections of the sky (their sharpness of outline caused perhaps by straggling wavelets which ‘cut’ and border them) lying on the dark, translucent water, tinted by vague reflections from the shore. Or, again, the white and dark marks, all together, suggest a definite, fixed reflection-picture of a fringe of bushes along the shore, with the bright sky beyond cutting in among their crowns, and show- ing here and there between them, lower down. The white on the head and neck and cheeks shows duly bright, while that on the throat, from which the higher spots are offshoots, is, in the bird’s normal life-postures, dull with shadow, and belongs mainly to the obliterative shading. In the resultant 67 water-picture it renders a duller sky reflection, mixed perhaps with under- water effect. The deep chestnut breast is blended above into dusky olive, on the fore- back and neck, while below it fades away into the immaculate white belly, the transition being effected by a series of triangular white flecks, extending downward in crescendo progression from the upper breast. (See, in con- nection with this and other points in my description, Plates III and IV.) This rich and lustrous chestnut, fleckless in its anterior and upper third, and glossed with purple and weak green, is an admirable picture of translucent, shaded water near the shore, either reflecting faintly the muddy bank and brown- stemmed bushes, or dimly revealing its own dusky, earth-colored bottom. Bounding the back edge of this chestnut, and separating it from the wing and side, is a bold ‘secant’ band of black and white (like that worn by certain teals, but stronger), vertically extended, but slightly crescentic, and pointing forward. Sharply ‘secant’—seeming fairly to cut the bird in halves—this marking is also intermediate in character between the reflection-picturing patterns of the head and the ripple-pictures on the flanks. For it depicts with almost equal fidelity at least two types of detail—a narrow sky vista reflected side by side with a dark stem or tree trunk, and a sky reflection glancing from the side of a sharp, single ripple. At least two evident purposes are likewise served by the beautifully graduated white triangles on the chest- nut breast, downward growing larger and larger until they completely veil the brown and blend it into the white of the belly. First, they are agents in the obliterative shading, and second, they admirably picture small glints of bright reflection on the faintly tremulous surface of quiet, shaded water. In this function they are the same as the punctate shine-pictures on the backs of rails, wood sandpipers, loons, etc., mentioned earlier in this chapter. Chestnut like that of the breast, but more strongly glossed with purple, forms a broad patch on either side of the Wood Duck’s rump, back of the ripple-picturing flank feathers. It is unflecked, and blends into the dusky and velvety-blue-green tail, just as the breast’s chestnut blends into the olive 68 back. Downward, this rump-mark blends into dusky-olive under-tail-coverts. Tail and rump together picture a patch of dark water, with blended, weak reflections, relieved by a streak or two of reflected shore-color in clearer defini- tion. These streaks, which are shining rufous brown, are formed by the central barbs of two or three of the loose-webbed, lengthened upper-tail-coverts ; they relieve against dusky green. The ripple-, sand-, and water-shimmer pictures on the Wood Duck’s flanks have been described in an earlier part of this chapter, but to complete this elaborate account we must revert to them, describing them in greater detail. The whole extent of the sides and flanks, from the crescent breastmark to the chestnut patches on the sides of the rump, is occupied by a uniform pat- tern of minute black vermiculations or undulatory lines, closely crowded over a ground-color of light brownish yellow. Below, this patch fades into the white of the belly; above, from a point barely in front of its middle backward, it is bordered by the remarkably bold and vivid ripple-pictures already men- tioned, formed by broad, alternate bands of snow and jet. These bands are on the tips of the longest of the grizzled feathers, and, as has been told, they cross them transversely, yet by the curling upward of these feathers the bands are made to form oblique or even horizontal streaks. Rising out of and sur- mounting the grizzled brown—which pictures either tremulous, opaque water, or, more vividly, a submerged bed of sand—these richly contrasted black and white streaks and crescents look wonderfully like a crowded company of fresh-made, hurrying ripples; just such, in fact, as the swimming bird him- self produces. Thus the ripple-marks he leaves in his wake and those that roll out from his further side are continued and repeated on his obliteratively- colored body, and this gives the final touch of perfection to his ‘vanishment.’ In the marvelous completeness of this ‘vanishment,’ this ‘invisibility’ in full and near view on quiet water, he is possibly unique among swimming birds. One may scan a Wood-Duck-haunted pool for many minutes, at close range, and fail to see the ducks that are floating on it; just as one often looks in vain for the Ruffed Grouse that is perching motionless in the apple tree. Like 69 the grouse, like the summer ptarmigan and the woodcock, the duck is, as it ‘were, ‘dissolved’ into its vari-patterned background, by perfect obliterative shading and picture-pattern. Two details of the male Wood Duck’s costume have yet to be mentioned, his gaudily-painted bill and his marbled under-wing-coverts. The bill is marked with bright yellow, red, white, and black, and in connection with the varied water-scene rendered by the bird’s plumage, it must often pass for a reflection-picture of bright-colored things like flowers, on the shore—or per- haps for the actual blossoms of water plants. But it is to be supposed that the flowerlike aspect of the bill renders its owner a still more direct and simple service, by separately disguising that implement of offense from the insects and other small but active creatures which form a part of his diet. A pied, flowerlike bill would probably, in the long run, succeed better in the capture of its agile prey than would a dull and normally tinted one, without deceptive color or markings. Of this the reader is to hear more in a later chapter. The use of the black-and-white marbling of the under-wing-coverts and axillars, shared by both sexes, is not surely apparent. But it seems likely that both the color and the markings of these feathers serve chiefly or wholly for ‘obliteration,’ coming into play when the birds are sitting and walking about in trees (a habit highly characteristic of the species), with wings frequently half spread. The ground color of white then becomes effective in neutralizing the shadow, as in the case of the belly, and the dusky specks and bars constitute a generalized obliterative pattern tending to ‘merge’ the wing, visually, into its freckled forest background. This pattern is in fact closely akin to that of many out-and-out forest birds. The female Wood Duck is colored much more dimly than her mate. Her wings alone are almost exactly the same, and fully as bright; otherwise, her predominant color, aside from the white of her belly, is ashen olive, lustrous with green and purple on the back, scapulars, and crown, verging toward brown on the sides and toward ash-gray on the cheeks, and reaching lustrous olive-green on the upper sides of the tail feathers. Her flanks show no traces 7° MALE WOOD DUCKS. Upper one: Sketch by Abbott H. Thayer, Lower one: Painting by Richard S, Meryman These paintings show one of the very common situations in which the boldest contrasts of a male Wood Duck’s coloring come into play in ‘preventing his showing his silhouette.. . His dark areas, with all their varied colors, here ‘become a part? of. the. -like-colored dark reflections in the water, and his white patterns exactly reproduce ‘the bright sky-reflections, go - that he is so to speak ‘dissolved’ into the scene.—A. H. T. EXPLANATION OF PLATE IV PLATE IV ANGER & CO BALTIMORE, of the sand and ripple pictures which are such important details in the ves- ture of her mate, being marked instead with blurred, broad streaks of pale yellowish gray, on a ground of olive-brown. On the whole, her costume lacks pronounced water-pictures, seeming to fit her rather for life in secluded recesses among reeds and bushes, and for perching among gray tree trunks, which she has frequently to do in the nesting season. When brooding, al- though most commonly quite hidden in a hollow tree trunk, branch, or stump, she is at times more or less exposed to outward view; and this fact also must have a bearing on the significance of her coloration. When she is sitting in the hollow end of a large broken branch, perhaps even with some of her fore- parts projecting beyond its rim, her obliterative coloration must often be most potent. (Audubon has figured a female Wood Duck in such a situation,and mentions it as not uncommon.) But aside from their probable connection with her ordeal of brooding, and guarding her ducklings among the reeds and bushes, her soft markings and colors and perfect counter shading make her at all times a thoroughly ‘obliterated’ bird—even though she lacks the bright and elaborate water-pictures of the drake. Both drake and duck are among the world’s most subtilely beautiful birds, and their obliterative coloration demands especial study. The Mandarin Duck (Aix galericulata) of the Orient, nearly akin to the Wood Duck in all respects, has an equally beautiful and still more remarkable costume, but one which is less unmixedly of the water-picturing type. In the drake’s dress there are a few important peculiarities which call for careful study of him in his home; but the female does not differ essentially from the female Wood Duck. 71 CHAPTER XII BIRDS OF THE OCEAN JURE white prevails in the costumes of the long-winged birds that habit- . ually range the open sea, and their patterns are further characterized by an almost total lack of small markings. In coloration as in environment, they are the antithesis of the sedentary and seclusive land birds which live mainly on grassy ground or in the mottled realms of woodland—such as the ptarmigans, grouse, goatsuckers, etc., described in earlier chapters. The Shore Birds (Chapter X) are a connecting link between the two extremes. As their average environment is much more plain and simple than that of the grouse or ptarmigan, so are their obliterative patterns much less richly and elaborately wrought. ‘The step is short from these birds of the barren bor- derland between earth and sea, to the long-winged rangers of the blank and hoary sea itself. Here are no sharp and fixed small forms at all, but only the eternal counterplay of two vast and simple fluent elements, atmosphere and water. ‘True, even in open ocean there are characteristic patterns made by the moving waves and ripples, and these are reproduced on some of the ma- rine animals, notably certain surface-swimming fishes. (See Chapter XXIV.) But the coloration of the long-winged, wide-ranging sea birds copies the prev- alent blankness of sea and sky and cloud. Though often resting on the sur- face of the water, they are of course less intimately bound down to it than the ducks, auks, murres, etc., being in fact eminently aérial rather than natatorial ; and this is in accordance with their wanting the wave and ripple pictures worn by many ducks and murres. Chief among these long-winged sea birds for delicate beauty of ‘oceanic’ coloration are the Larid@, or gulls and terns. 72 Nearly white all over though most of them are, in the adult plumage, they are yet obliteratively shaded, having ‘“‘mantles” of darker or lighter bluish gray on the back and wings—and in the case of many terns, crown-caps of black— while all the remainder of their costume, with the exception of a few more or less dark-marked quill feathers, is, in most cases, fleckless white. Black markings aside (these we shall discuss later), this obliteratively disposed com- bination of soft, water- and cloud-like pearly gray with bright, shadow-ab- sorbing white is just such a coloration as insures its wearers, whether flying or swimming, the greatest average inconspicuousness against the ocean. Often they show light against dusky water, but just as often they show dark against water brightly sky-lit; and hence in many intermediate cases they must pass unseen, matching their ‘background’ as does the ptarmigan or grouse in its appropriate domain, although so much less intricately. All this concerns the aspect of the gulls as seen from above, against the ocean. But they have little to dread from flying enemies, and the more vital service rendered by their col- oration is doubtless concealment against the sky above, jrom the eyes of aquatic animals below them. Like the Snowy Owl, the white herons and egrets, and, in part, the skunks, deer, antelopes, etc., to be described ina later chapter (Chapter XXII), these ocean-rangers are admirably equipped for incon- spicuousness, in a great many views, against the sky itself. Thus, even to the eyes of their aquatic enemies and aquatic prey, they wear the universal com- plete obliterative coloration. Pure white or largely pure white though they are, they must often relieve darkly against the sky, as always when seen directly overhead. In many views, on the other hand, they ‘melt away’ into their skyey backgrounds, as do the white, masking rump-marks of many ruminants, and the white back- and head-patterns of many grubbing carnivores (Chapter XXII), etc. As the normal background of these sea birds is the unbroken sky, varied only by unbroken, sky-reflecting ocean, so their prevalent coloration is such as achieves pure and simple sky- and ocean-picturing. On most of the true gulls (Lavine) the white of the rump, tail, and entire underside extends also to the head and neck. The head’s consequent lack of counter shading is re: evidently more than compensated by the sky-matching power which uniform, pure white gives to this most vital and most dangerous portion of the gull, either when he is resting on the water, with head held erect, or—and perhaps more particularly—when, as he flies or swims, his head is stooped toward, to, or even beneath, the surface, in search of food. White or largely white-marked heads are common to a good many other birds, not counting the habitual swimmers, which get their living from the water; witness the Bald Eagle, the Osprey, the Great Blue Heron, etc. In all these cases they perform the same service of ‘obliteration’ agaist the sky. Some gulls, on the other hand, such as the Black-head (Larus ridi- bundus), of Europe, and the Laughing Gull (L. aéricilla), of America, have dusky hoods enveloping the entire head. All or nearly all the kinds thus marked are inhabitants of bays and lakes and marshes rather than the open sea. Furthermore, the dark hood is worn only by the adults in the breeding season, when, amid the blackish mud and dusky shadows of the salt marsh or inland swamp, they well serve as ‘ruptive’* masks. So do the jetty crown-caps of nesting terns—except that these belong to obliterative shading as well as to ‘ruptive’ pattern. (See Fig. 55.) Like the gulls’ hoods, they are as a rule features of the breeding season only—in the autumn largely giving place to white, the regulation sky-matching color. But the black markings on the quill feathers both of gulls and terns are worn throughout the year, and probably serve both as ‘distractive’ marks + when the birds are fishing, and as combined ‘distractive’ marks and ‘picture patterns’ when they are brooding on shore amid shadows and other dark landscape- details. For the most part, however, the coloration of these gulls and terns in adult plumage is suited to the sky and sea rather than to the land, and they are apt to be conspicuous on their breeding grounds, by virtue of their paleness. Their downy young, on the contrary, are almost always well ‘obliterated’ * See Chapter XIII, p. 78. t See Chapter XXII, p. 151. 74 by counter shading, color, and near-ground markings.* (See the young gulls in Fig. 75.) Mottled brown, dusky and gray costumes of various degrees of darkness are worn for two or three years by the young of the larger gulls, and it is a noteworthy fact that during this period they are more addicted to living on and about mud-flats, marshes, and muddy lagoons, than are their white and free-sea-ranging parents. Among the other groups of long-winged sea birds, there is a good deal of diversity in coloration, but at the same time a persistent tendency toward whiteness and the lack of small markings. Sky-matching costumes, indeed, reach high and simple development among the gannets, tropic birds, alba- trosses, fulmars, and others. The smaller jaegers or robber gulls (Stercorarine) have in the usual adult plumage full obliterative shading, being fuscous brown or slaty gray above, and white below, sometimes with small markings (dusky flecks) on the breast and sides; and their young wear a heath- and grass-picturing pattern of brown and dusky. But the symmetry of these facts is marred by the existence in at least two of the three or four white-breasted species of a second adult color- phase, in which the costume consists of sooty brown with a comparatively slight counter shading. Here, as in the case of the black leopards and jaguars (see Chapter XXI, p. 133), there may be something to discover in the way of cor- responding varietal peculiarities of habits. But jaegers are parasitic harriers of other birds, and prodigiously swift of wing, so that, except during the nesting time, they doubtless have comparatively small need of disguising- coloration. Strange as it may seem, however, a good many other aérial sea birds are colored much like the melanistic jaegers—i. e., almost uniformly dark brown or black above and below. Such are several of the Tubinares,— shearwaters, petrels, albatrosses. But almost all these birds, in addition to being largely nocturnal, nest in dark earth-burrows or rock-fissures, and this habit has doubtless a significant connection with their queer coloration. Many other species of the same families, as well as various long-winged sea * See Chapter XIV, pp. 82 and 83. 75 birds of other orders, are obliteratively shaded, from pure white to dusky brown or gray, with or without connecting middle tones. Though often very inconspicuous against the sea, such dark-backed birds are of course less well equipped for ‘vanishment’ against either sea or sky than are the beautiful white and pearl-gray gulls and terns. These have, indeed, the very acme of oceanic obliterative coloration. 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CHAPTER XIII BIRDS, ETC. THE INHERENT OBLITERATIVE POWER OF MARKINGS. ‘RUPTIVE’ AND ‘SECANT’ PATTERNS, ETC. P to this point we have considered markings and patterns almost solely as adjuncts and dependents of obliterative shading. As far as ground- haunting species are concerned, this function of markings seems by far the most important, but they have yet a separate and inherent significance, which among non-terrestrial species is often the dominant feature of disguise. As we have seen, perfect uniformity of coloration makes a thing conspicuous, allowing every part to assume exactly the aspect dictated by its own form, without exaggeration or omission. Markings, on the other hand, of whatever sort, tend to obliterate,—to cancel, by their separate and conflicting pattern, the visibility of the details and boundaries of form. The main solidity, and its details, are shown by graduated light-and-shade—the outline, the externai contours, by relieving either light or dark or differently colored against the background. To all this markings are unfriendly, both on objects actually monochrome and therefore visually not so, and on objects which present, with the aid of counter shading, a perfectly monochrome appearance. Rapid and manifold are the vicissitudes of illumination and relation to background of a moving bird or butterfly among trees and open spaces. Now it is dark against a sky vista, or against brightly-lighted foliage, and the next instant, by some slight change in its position, or in that of the beholder, it shows light against dark shadow-spaces. (See Figs. 56-57.) Delicate picture-patterns cannot avail against these grosser ‘visibilities,’ but strong ‘secant’ and ‘ruptive’ patterns can. If the bird’s or butterfly’s costume consists of sharply contrasted bold patterns of light and dark, in about equal propor- 77 tions, its contour will be ‘broken up’ against both light and dark—light failing to show against light, dark against dark. Such is apparently the basal and predominant use of almost all the bolder patterns in animals’ costumes. Often such bolder markings play a part in subtler schemes of picture-pattern; but, on the other hand, they sometimes work independently of obliterative shading. ‘Secant’ patterns, however, are almost always in its service, even when they have some share of independent effect. A good example is the longitudinal light-colored stripe on the scapulars or wing feathers, so very prevalent among obliteratively colored birds—particularly those with highly developed picture-patterns. It is found in its perfection on certain sparrows and many gallinaceous birds. In almost every case it clearly pictures a horizontal stick or grass-blade, with its shadow under it; but, picture or no picture, it tends to cut the aspect of the bird in two. This marking'is found also on certain kinds of wood frog, and on toads. (See Chapter XXIV.) There are also vertically ‘secant’ markings, e. g., the white or black-and- white breast-bands of some teals (Nettion), and of the Wood Duck (Azx), both mentioned in an earlier chapter. ‘Ruptive’ markings, in general, are bold, massed patterns of contrasting shades and colors, disposed at seeming haphazard over the animal’s body, but in reality arranged according to the rigid laws of disguise. Among birds thus marked, some of the best examples are sea fowl, Eider Ducks, for instance. Male Eiders, with their big, con- trasting patches of black and white and buff and green—or grayish blue— are doubtless very inconspicuous in deep ocean water among ice cakes; while their brown, grass-patterned mates are well fitted for the task of brooding their eggs on the dry shore. The non-counter-shaded male Harlequin Duck (Histrionicus histrionicus), likewise, is in aspect cut to pieces by its queer, black-rimmed white markings, which look like floating bits of ice, or patches of snow on rocky shores. Many other sea ducks wear kindred markings, and so do many land birds and even quadrupeds and other animals. The more crudely-blotched black and white patterns of certain woodpeckers, the black caps and white cheeks of nuthatches, and the various bold head-markings 78 rs | & Fie. 56. Two artificial butterflics, one dusky and one light, seen against a dusky tree- trunk; the light one conspicuous, the dusky one barely distinguishable. Fig. 57. ‘The same two artificial butterflies seen against alight background, the dusky one con- spicuous, the light one barely distinguishable. These two pictures. show that no one color will conceal an animal that must move across the varied.and varying face of nature. In our pictures of artificial models we have purposely ignored the factor of interposed vegetation, which in nature plays so large a part in abetting ‘vanishment’ by obliterative costumes. For we are here studying main principles, divested as far as possible of accessories. Fig, 59. Chestnut-sided Warbler (Dendroica pensylvanica) (and Catbird). [Cf Fig, 58.] Photographed from life by F. H. Herrick, Courtesy also of G. P. Putnam’s Sons. Counter-shading and general- Fi, 58, Chestout-sided Warblers (Dendroica pensyleanica), ized obliterative background-picturing patterns. Photographed from nature by Francis H. Herrick. Courtesy also of G. P Putuam’s Sons. Fic. 60. Blue Jays a their nest, amid foliage. [See p. 116, Chap. xi j Fic. 61. Chickadee at nest hole Light-and- shadow-picturing general- ized obliterative pattern, most potent in snowy win- ter. Notice how the black head-markings ‘merge’ with the dark hole beyond. Photographed from life by Finley and Bohlman. Courtesy also of ‘The Condor.” Fic. 62. Oystereatcher (Haematopus ostralegus) close to its nest on rock ound. Counter-shading and ‘ruptive’ pattern, ete. a Sea Photographed from life by Cherry and Richard Kearton. Courtesy also of Cassell & Co. Fic. 63. Guillemots on rock, showing ‘ruptive’ coloration. Seen against the sky or (brightly sky-lit sea) they ose,’ so to speak, their light parts; seen against the shadowed rocks they ‘lose’ their dark parts, and thus their bird-like contours are disguised, Photographed from life. Here reproduced through the kind of Prof. F. A. Lucas. of North American Wood Warblers (Mniotiltide), are a few of the many ex- amples among the smaller land birds. (See Figs. 58-61.) It might be supposed that a marking in such rank violation of the para- mount ‘obliterative’ principle as a jet-black breast or belly, with lighter tones above it, could not fail to make a bird exceedingly conspicuous; but this is by no means true. Such a marking, especially when it ends sharply against a lighter tone, thence upward counter shaded, tends in aspect to detach itself from the rest of the bird’s dim body, and to unite with the background as a hole or other very dark detail, thereby ‘breaking up’ its wearer’s character- istic form. This is the coloration for instance of the Black-bellied and Golden Plovers (Charadrius and Squatarola) in summer plumage, and of the adult male Massena Quail (Cyrtonyx montezume and its subspecies) of Mexico, etc. In the case of such birds as the male Eider Ducks, however, there is virtually no counter shading above or below,—the obliterative scheme con- sisting almost wholly of a series of ‘breakages’ achieved by sharply contrast- ing patches. All these bolder schemes of pattern mask their wearer in a distant view and in many views, whereas the delicate picture-patterns based on perfect ob- literative shading play their full part only in a near view and against one par- ticular type of background. In such a case, details of light-and-shade and minor surface markings count for much. But give the object a greater dis- tance from the beholder, and manifold vicissitudes of position and illumina- tion, and it is contour that betrays it—contour, relieving with varying degrees and kinds of conspicuousness against varying backgrounds. Combating this principle, Nature has given many of her animals bold and _ brilliant ‘rup- tive’ patterns, which insure them, in lieu of elaborate and single background- matching, the highest average of fragmentary background-matching, in many situations and from many view-points. (See Plates V and VI.) 79 CHAPTER XIV SPECIAL FUNCTIONS OF MARKINGS. BIRDS, ETC. PROTECTIVE COLORATION OF NESTLINGS EEDING henceforward the axiom established by the foregoing chap- ters, viz.: All markings and patterns whatsoever are, under ordinary out- door conditions, unjavorable to the conspicuousness of the thing that wears them, we will examine further special phases of disguising-pattern in the costumes of birds and other animals. A noteworthy type of generalized picture-pattern occurs, the world over, on the wings and tails of hawks and owls. Most of them have, in some plumage, conspicuously banded quills, whose pattern shows to best advantage on the underside. On some: kinds, like the Goshawks (Astur atricapillus and A. palumbarius) in juvenile plumage, these bars on the quill feathers form, when the tail and wings are broadly and fully expanded, a large series of almost complete concentric circles. Potent must be the obliterative effect of such a pattern, to the victim at whom the hawk is dashing, or above whom he is momentarily poised, with widespread tail and wings. The reduplicate circles of alternate light and dark, extending from the hawk’s dim, streaked body to the very tip of his great flight-feathers, and averaging more sharply visible than the actual contours of the wings and tail, practically efface those members, so that for an essential instant he is as it were dissolved and blended outward, from a central core, into the banded and streaked promiscuous pat- tern of the twigs and branches behind and all about him. His menacing body is the inconspicuous center of a maze of forest-colored circles, bewilder- ing and confounding to the terror-stricken creature on whom he is about to pounce. (See Figs. 64-66.) The light bands in these patterns of hawks’ 80 Fic. 65. Part of a Goshawk’s wing seen from below against pine twigs and sky. [Cf. Figs. 64 and 66.] Fic. 64, Stuffed Goshawk (Astur atricapilius, young) in winter pine woods, seen from below as the hare or grouse would see him, wonderfully matehin g, with the help of counter-shading, his barred background of twigs, sky-glints, etc. Fic. 66. The same young Gos- hawk (.Astur atricapillus) laid on its back on the forest floor and looking conspicuously bright. . This reveals the part played by counter-shading in the ‘twig matching’ shown by Figs. 64-65, Fic. 67. Baby Golden Plover’ (Charadrius Jfulvus). Counter-shading and blotchy ground- picturing pattern, eye-masking pattern, etc. Photographed from life by Cherry and Richard Kearton. Courtesy also of Cassell & Co. Fic. 68. Ringed Plover (Aegialitis hiaticula). Fye- masking and ‘obliterative’ shadow-and-bole-picturing pattern. Wis black marks, as the reader will see, ally themselves wonderfully with the dark fissures in his background. Photographed from life by Cherry and Richard Kearton. Courtesy also of Cassell & Co. ’ Fie. 69. Lapwing (Vanellus capella) on 1ts nest, Obliterative shad- ing, eye-masking and shadow-picturing oblit- erative patterns. Photographed from life by Cherry and Richard Kear- ton. Courtesy also of Cas- sell & Co. wings and tails are almost always very translucent, and contrast brightly with the opaque dusky bands, even when the wing or tail is seen from below, and deeply shadowed. As the pictures show, the dark marks are just of one ‘value’ with the darker twigs and branches, and the light bands between of one value with the interspaces of foliage transfused with skylight, against which the branches and twigs ‘relieve.’ Another noteworthy detail of the independent efficacy of pattern is the masking of birds’ and mammals’ eyes.* Markings of this kind occur chiefly on predatory mammals, and on birds. See, for instance, the young plover’s head in Fig. 67. Notice the dark ring surrounding the eye, and the longi- tudinal dark mark at either end of it—a ‘stringing out’ of the eye’s dark tone. Patterns like this, but often bolder and more varied, surround the eyes of many birds and a few quadrupeds. The lengthwise stripe, especially— the dark line which the eye seems scarcely to interrupt—is a very common marking among birds. This seems to be a ‘conventionalized’ eye-masking pattern, like the conventionalized ground pattern of larks and sparrows. It is very effective, however, as it completely breaks the eye’s otherwise conspic- uous circular or oval outline. Other, more varied patterns achieve this in a still higher degree, often seeming to absorb the eye into themselves as one of the details of their irregular form. (See Figs. 67-72.) Light-colored eyes, * Many. herbivorous mammals have dark and lustrous eyes, surrounded by a more or less dis- tinct pale-colored ring. This, however, belongs to the obliterative shading, playing its full part of shadow-neutralizing when the eye is shut. Very likely the noticeableness of the open eye does the animal good service when it is skulking, inasmuch as it increases the likelihood that the skulker will know the instant he is surely detected by an enemy. All the rest of him is almost or quite ‘oblit- erated,’ but there is still much chance that a predatory creature, hunting by scent as well as by sight, may discover him. Because of this chance, he must be alert, ready to leap and run at any moment, and must keep his eyes open, even though they may help to reveal him. But their very conspicu- ousness increases the chance that the predator, having followed his quarry up by scent, or coming suddenly upon it, will look first directly at those its points of vital watchfulness, thus giving it the beneficent timely warning—the sure and instant signal that the crouching ‘ game is up ’—which would be lacking if the hunting-beast first recognized some other portion of its quarry’s body. Encircling marks and all, the eyes are small details of the ‘obliterated’ creature, and cannot attract the pred- ator’s attention unless he comes almost within striking distance. 81 especially those with narrowly slit pupils, are often very inconspicuous, in themselves. The green and yellow eyes of many felines, especially when they are surrounded by irregular fur-patterns of about the same shade, are insid- iously unapparent and elusive, ‘merging’ well with leaves and foliage-vis- tas, etc. This obliterative coloration of cats’ and other predatory creatures’ very eyeballs must be a great aid to them in their stealthy stalking of their prey. An eye like that of the Copperhead Snake (Chapter XXIV, Plate XT), with its narrowly slit pupil, is as well concealed as any part of the creature’s obliteratively colored body. One more subject which must have a place in this rather miscellaneous chapter is the coloration of birds in downy nestling plumage. Passerine birds—most of them at least—are born naked and absolutely helpless, re- maining in this condition for days. But they are almost always domiciled in substantial nests, which in their turn are usually hidden amidst foliage, so that the youngsters are well shielded from their foes. Such birds have no true downy plumage, but pass from nakedness into a coat of frowzy contour- feathers, marked somewhat differently from those of their parents, though often much resembling them. But there is a great group of birds, including most of fhe members of most of the orders outside of Passeres, whose young are born with a full downy covering, which they retain for many days. Such are the grebes, ducks, geese, gulls, terns, rails, shore birds, Galline (grouse, etc.), goatsuckers, hawks, owls, etc. Of these the terrestrial (and aquatic) forms concern us most, for they are more exposed to danger, and have more highly developed protective co:oration, in the infant state, than the nesters in trees. The terrestrial (and aquatic) assemblage may be again divided into two sections, one including the species whose young are for a time sedentary and helpless, and the other those whose young are active and alert from the moment of birth, and leave the nest almost at once. Of the active sort are grebes, ducks, rails, sandpipers, and .all the gallinaceous birds; while goat- suckers, and, to some extent, gulls and terns, belong to the sedentary type. Young grouse and other Galline acquire the power of flight, along with con- 82 ~ Fie. 70. Killdeer Plover on its nest. [Cf. Fig. 71.] Photographed from life by Dr, Thos. 8. Roberts. Courtesy also of *‘ Bird Lore.” Fig. 71, Killdeer Plover over its nest. Obliterative shading, shadow-picturing patterns, ete. Photographed from life by Dr. T. S. Roberts. Courtesy also of ‘‘ Bird Lore.” Fic. 73. Nighthawk chick, as in Fig. 74, Photographed from life by F. H. Herrick. Fig. 72. Young Killdeer Plover, wonderfully ‘obliterated’ by counter- shading and ground-picturing pattern. Photographed from life by Finley & Bohlman. Fic. 74. Nighthawk (Chordeiles virginianus) chick—obliteratively-shaded d further ‘ Mal i Sink Gistne aie 9 ) y , and further ‘merged’ into its background by blotchy Photographed from life by F. H. Herrick. Courtesy also of G. P. Putnam’s Sons. Fie. 75. Baby Conm- mon Gulls (Larus canus). Spotty ground-picturing pattern, like theshadows among pebbles, ete. Photographed from life by C. and R. Kearton. Fic. 76. Baby _ Cur- lew. [('t. Fig. 73.] Photographed from life by C. and R Kearton. Cour- tesy also of Cassell & Co. " Eis _" Young Crested Grebes. Highly-specialized obliterative picture-pattern (with obliterative shading. ° Photographed from life by Cherry and Richard Kearton. Courtesy also of Cassell & Co. Fie. 78. Bahy Red-breasted Mergansers (Merganser serrator). Fic. 79. Sketch suggested by Water-shine-and-shadow patterns, etc. show how closely they represent a little wet spot in a swamp. Photographed from life by Cherry and Richard Kearton. Courtesy also of Cassell & Co. the young mergansers in Fig. 78 to Fic. 80. Young Horned Grebes on their nest. Obliterative shading and specialized ground-picturing patterns. [Cf. Fig. 77.] Photographed from life by Herbert K. Job. Fie, 81. Baby Woodcock (Philohela minor). Picture-pattern, based on counter-shading, Notice, here and in Fie. 82. Baby Woodcock the next figure, the perfect picturing by these young birds’ patterns of dark holes and lighted details. (Philohela minor). (Cf. Fig. 81.] Photographed from life by E. G. Tabor. Photographed from life by E.G.Tabor. tour-feathers and elaborate picture-patterns, at a remarkably early age— while they are still mere chicks—but with this and a few smaller exceptions, there is much sameness in the baby plumages of the many members of these widely separated orders. (See Figs. 67 and 72-76.) Pure obliterative shad- ing is universal among them, occurring fully developed even in species whose adult plumages lack it. Their color varies correspondingly to that of their normal surroundings; those which are raised on the rocks, like terns and nighthawks, being grayer, as forest-hatched grouse and whip-poor-wills are browner; but there is a prevailing tone of dim-brown ground-color by which the variations are connected. The patterns of these youngsters, too, are nearly all much alike. Grebe chicks, young woodcocks, and some young ducks, with their fantastic obliterative spots and stripings (see Figs. 77-82), are exceptions; but most of the other kinds, from gulls to goatsuckers, wear on their baby-down a soft, blotchy speckling, which seems to be the nearest approach to a near-ground picture that the weak, hairy feathers can produce. But this pattern serves admirably to merge the little, counter-shaded puff of a chick into its immediate background of rock or pebbles or leaf-strewn forest earth. The ‘obliteration’ indeed, strongly abetted by the chick’s form-belying, ambiguous fluffiness, is often perfect. (See Figs. 48, 72, 74, and 82.) Young ducks and geese, living much among green reeds and grasses, are more or less strongly tinted with greenish yellow, but their markings are usually very simple. Baby plovers and sandpipers (Figs. 72 and 76) have a dainty and effective pattern, though still more or less of the blotchily speckled type, and are counter-shaded to a nicety; as are, indeed, almost all terrestrial downy chicks. 83 CHAPTER XV BIRDS. OBLITERATIVE COLORATION AND MASKING OF BILL AND FEET FOR OFFENSIVE PURPOSES NDER this heading I shall include the pattern-bearing ‘‘pantaloons” of hawks, the prevailing pale or bright coloration and occasional counter shading of their tarsi and feet, and the various bright colors and occasional flowerlike appendages of the bills of jacanas, gallinules, anhingas, herons, etc. The spreading shields of leg feathers, or “‘pantaloons,” worn by almost all hawks and some owls, and almost peculiar to them, must naturally be supposed to have some connection with their predatory grabbing-habits. But what is the connection—what the function of these pantaloons? One use they have, and a seemingly important one, is this: they act as masks of the dangerous talons, by making them appear merely as spots merged into a moving veil of patterned feathers. If the extended legs and feet were stark and narrow, without adornment, they would be much more clearly visible to the animal attacked. As it is, the deadly feet descend in a broad and blurring haze of mottled feathers, which must certainly reduce the victim’s chances of successful dodging. The bold form of the hawk’s long leg is veiled by these tufted feathers, and still further concealed by the pattern of spots or transverse bars which these feathers bear. On some species, such as the Rough-legged Buzzards (Archibuteo) of the North, and the Harpy Hawks (Spizaétus) of South America, the entire tarsus is concealed by feathers, ‘usually covered with bold patterns (sharply cut by transverse barrings in the Harpy Hawks); but most species have the tarsus as well as the foot bare for action. Most owls, on the other hand, have everything but the very claws 84 muffled with feathers. The bare feet of hawks are usually very light in color —yellow or livid green or orange,—oftenest yellow. These pale, bright colors have a deceptive effect, inasmuch as they are less characteristic of hard ani- mal substances than of leaves and flowers and grasses. Furthermore, they tend to prevent the feet from looming darkly conspicuous, as they otherwise would in the shadow of the body. In the case of the Osprey or Fish Hawk (Pandion), whose spur-scaled foot has such a marvelous tenacity of grip, Nature seems to have used her utmost skill in the manufacture of a perfect fishing weapon. Not only are the tarsus and toes pale watery blue and green in color, but there is even a perfect obliterative shading from the top to the bottom of the foot. The pantaloons are obsolete, and all the leg feathers are immaculate white—details in most evident harmony with the habits of the bird. Spreading leg feathers would obstruct action in the water, and mark- ings would be equally out of place, since they belong properly to the inhabi- tants of the streaked and mottled realms of field and forest. Pure white, on the other hand, is less conspicuous than any other tone or color when seen from below against the sky, or against the body of the bird above, whose interposed opacity additionally steeps the leg in shadow. Of one class with these masking-devices of hawks’ legs and feet are the bright and motley bill-colors of predaceous wading birds‘and swimming birds. Whatever may be their other functions, these gaudy colors well serve to dis- tort, conceal and mask the powerful beaks, to the vision of the fishes, frogs, insects, etc., in the capture of whom they are employed. Some of these beaks, such as those of many herons, of anhingas, etc., are marked with bril- liant reed- and water-colors, in various forms and combinations. Others, such as those of rails, gallinules, jacanas, etc., are like bright leaves, stems, or flowers—green, yellow, orange, or scarlet, as the case may be, in varying pat- terns, sometimes combined with water-like blues or purples. (Certain South American frogs are clad in these same colors. See Belt’s ‘“‘The Naturalist in Nicaragua,” p. 321.) Some of the jacanas have flat, erectile lobes or wattles, of a rich red color, set about the base of the yellow bill, like red petals around 85 a golden corolla.* Many of these wading birds have also reed-colored or otherwise deceptively painted legs and feet, which may often save them from being snapped up by alligators and turtles, and must also help them in their hunting. The study of the colors of birds’ bills and feet in relation to their habits and environments is a large field in itself, and we in this chapter have barely peered over its borders. But there seems little room for doubt that the gen- eral principles here briefly stated are dominant or at least very important ones. *Tt is most noteworthy that scarlet and yellow, the colors of the flowers and leaf stems of the “cow lilies” which abound in North American swampy ponds, are also to be found on a great many of the animals that resort to these places. The Wood Duck, the Gallinules, the Red-winged Black- bird, and the Painted Tortoise, for instance, all wear scarlet, black (or dark blue) and yellow, just as does the surface of such a pond, with its black shadows between the lily pads and flowers. Even the long-billed Rails of the same region have (in spring and summer) coral-colored beaks. Indeed, red, orange and yellow seem to be very common colors of aquatic vegetation and of swamp birds’ beaks, the world over. From a hawk’s point of view, as he flies over swamps and ponds, it is not merely the black water itself that these species match, but also the dark mud, and, in general, the dark spaces between the vegetation. From overhead, the Red-winged Blackbird, even when perched on top of the bushes, matches—or simulates—the shadowy spaces beneath; and his faintly discernible outline is easily rendered indistinguishable by the conspicuousness of his scarlet and yellow cow-lily picture (just as the letters in Fig. 106 are made illegible by their patterns)—in spite of his lack of counter shading. In fact, though the ‘Redwing’ often perches high enough to show black against the sky, ¢o us, to the soaring hawk he is commonly matched to the mud, as much as rails or coots.—A. H. T. 86 CHAPTER XVI BIRDS, CONTINUED. ‘OBLITERATION’ BY IRIDESCENCE. CHANGEABLE COL- ORS IN GENERAL; THEIR PART IN WATER-PICTURING COSTUMES, ETC. RILLIANTLY changeable or metallic colors are among the strongest factors in animals’ concealment, and go far toward achieving ‘oblit- eration’ without counter shading. The quicksilver-like intershifting of many lights and colors, which the slightest motion generates on an iridescent sur- face, like the back of a bird or the wing of a butterfly, greatly obscures the visability of that wing or back, as such, tending to make it ‘blend’ inextri- cably with the gleaming and scintillating, labyrinthine-shadowed world of wind-swayed leaves and flowers. Even without motion, the animal’s sur- face, which would show all in its true place and plane if it were plainly col- ored, is by its iridescence made to appear ‘dissolved’ into many depths and distances. Here is a bright place that stands out near and clear, there a dark area that melts away into“indefinite remoteness, and so on. Rarely does such a ‘changeable’ surface, out of doors, reveal itself fully and truly to the eye. Hence, iridescence is, as I have said, one of the prime factors of dis- guise, and quantities of creatures profit by it. As a general rule, it is found on animals that spend much of their time in lively motion. As we have seen in Chapter XIII, the more minutely detailed forms of obliterative coloration are not adapted to animals of this type. Seldom “‘lying close,” they need a bold and simple disguise to lessen the conspicuousness of their movements. This is found, as we have seen, in ‘ruptive’ pattern; and iridescence is equiv- alent to ruptive pattern with an added gift—the power of motion. Ruptive pattern, that is, with no fixed form, but mutable like the landscape itself. 87 When the iridescent-costumed animal is still, the slightest change of light upon him will cause a bewildering play and movement of his colors; and when he moves, his colors’ varied dancings are far more apt to belie and perhaps con- ceal his motions, than to accentuate them. For instance, the gleaming high- light, the central point of shine on the back or side of an iridescent bird, say a turkey gobbler or a peacock, may move backward on the bird’s surface while the bird himself moves forward, so that to the observer’s eye it seems to be standing still, and since by virtue of its very brightness this spot will hold the attention, it must often happen that the bird seems to be motionless when he is in fact slipping away. It may be objected, and truly, that such decep- tions as this are of only momentary effect. But the reader should realize, in this case and in all kindred ones, that it is just these tiny, trivial seeming moments that often tip the balance toward escape or capture, toward life or death, in an animal’s career. The predatory animals and the animals they prey upon have been developed together, and their powers of capture and escape interadjusted to a nicety. The business of the one kind is to hunt and kill, of the other to evade their clutches; both are Nature’s children, both are favored by her, and both grow up and survive as races in the same woods and fields. On the one hand, Nature fits the hunters to kill enough of the weaker animals to keep themselves alive as a race, on the other she fits the weaker ones to escape so often that their race too shall not succumb, that the hunting race cannot overstep its boundaries; that, in short, the even bal- - ance between hunters and hunted shall in the long run be maintained. On the hypothesis of Natural Selection, we must suppose that there is the closest rivalry between the two opposed developments; like the continual competition which has long been going on in man’s domain, betweén the development of armor and the development of explosives and projectiles. To their rivalry alone is due the wonderful and ever-increasing excellence of both develop- ments, in the case of the human instruments of destruction and defense; and just such, if we believe in Natural Selection—or, in fact, on any hypothesis that recognizes adaptation as something more than accidental—must we sup- 88 pose to be the way with predators and prey in savage nature. In any case, it is obvious that, as things stand to-day, the very smallest items in aid either of the hunters or the hunted must be of vital importance. Eagles and tigers are not more clever at catching than their quarries are at escaping, hence the slightest additional aid may save a quarry’s life. Just such an aid is the mo- mentary deception effected by the contrary movement of a spot of iridescence, as described above. Hindered but for an instant, the pursuer may be wholly balked, for that instant may enable the quarry to slip into cover, or take wing, just in the nick of time. But the larger deceptions achieved by iridescence, viz., nearly complete ‘obliteration,’ in one form or another, are still more potent and important. A brightly changeable plumage is like a sumptuous wardrobe, packed into marvelously small compass—many different dresses combined in one, without the loss of their individual identity. The Mallard Duck (Anas boschas), for instance, has in some lights a bright green ‘‘speculum”’ on its wing. In other lights this mark is blue, in still others, purple. In addition to the look of life and motion (like that of water and glittering vegetation) which the change- ableness of this marking gives it, it also makes it far likelier to match the bird’s background than any fixed tint could. Water, mirroring whatever is above it, varies interminably in color, and so do foliage-vistas and other land- scape details. Were the Mallard’s speculum of a uniform blue, it would serve its full obliterative use only when the bird’s background happened to show areas of just that hue. But containing as it does the whole scale of colors from grass-green to reddish purple, displayed one after another by slight changes in the bird’s position, it is equipped for perfect color-match- ing, if often only in flashes, with many sorts of background. Indeed, even in most single views, and without motion, the speculum shows such a range of lustrous color that some part is likely to be an exact match for one of the back- ground tints. (Although this marking is usually almost hidden while the ducks are swimming, it often comes into full view when they walk or stand, as on river-banks or tussocks, or in reed-grown shallows.) Still more marked 89 and striking applications of the same principle occur among bright-colored land birds, notably tropical ones. There are species with almost the entire plumage highly iridescent, changing perhaps from bronzy red to emerald green (or even to blue), according to the bird’s position relative to the source of light and the beholder. Such for instance are some of those exquisite aberrant kingfishers, the jacamars (Galbulide) of South America. One of them at least, Galbula ruficauda, the only kind my father and I have studied in its native forests, is exceedingly hard to discover when it is sitting stock- still on its exposed look-out perch low down among the trees. It affects semi-cleared areas, and the open reaches and borders of the forest, where there is much variety in the colors of its background, and there is no dis- puting the fact that its beautifully rich iridescence aids it greatly in escaping notice in these places. Its colors shift with the shifting scene, as it were; they counterfeit the airy life and changefulness of the encompassing leafy landscape, played on and vivified by wind and sun and shadow, not to speak of the changes wrought by the movements of the beholder. The environing landscape contains, in one or another degree of purity and brilliance, all the colors of the rainbow; and the tints of the jacamar’s plumage likewise range through almost the entire spectrum. Often the bird’s background is bluish green, often all his upper parts show nothing but that color; often, again, his background is rich reddish bronze, just such as his feathers show in certain other lights, and so on. Of course the changes in the bird’s color are inde- pendent of the changes in his background, but in the long run his lively versa- tility of tint must enable him much oftener to match his versatile background, in part at least, than he could if his colors were unchanging. ‘The jacamar is also a bird of the deep forest, however—not by any means confined to the bright-colored half-open regions—and accordingly he wears on his underside the regulation forest brown of tropical woodland animals. (See Chapter XIX, p. 107.) If a bird wears colors characteristic of his environment, it is not necessary for his concealment that he should momently ‘match’ his back- ground, even in part. A spot of brown, for instance, introduced where such go a spot might well occur in the background, will readily pass for a real back- ground-detail. There are two kinds of changeable color among birds. One is iridescent or metallic color, such as we have been considering, and the other, worn by many of the most gorgeous species, is what may be called ‘dead’ or sheen- less, changeable. In this there is no sudden glinting or intricate intershifting of bright colors, but merely a change in the general tint of the lusterless and uniformly-colored surface, dependent on the complete change of its position relative to the source of light. This kind of coloration lacks all the subtler magic of obliterative power possessed by iridescence, but shares to some ex- tent its advantage of adaptability to often-varied backgrounds. Many of the most brilliant blues, greens, and purples in the plumage of birds are of this lusterless type. Good examples among familiar species are the common European Kingfisher (Alcedo ispida), and the North American Indigo Bunt- ing (Passerina cyania). When such a bird is between the beholder and the source of illumination, its brightest color is a deep blue, or sometimes even purple. When, on the contrary, the beholder has the source of illumination behind him, and the bird in front, so that the light, striking it fully and fairly, is reflected directly back to the eye, the parts which were before dark blue or purple are clear, light green, sometimes even golden green or almost yellow. (For the best effect, particularly in the display of the green extreme, the bird should be seen head-on.) Some birds which are wonderfully inconspicuous in their normal haunts have this type of coloration. Such for instance is the American Purple Gallinule (Jornis martinica), mentioned in an earlier chap- ter. The changeableness of this bird’s color, however, is mainly from bright to dim, rather than from green to purple, and does not play a very important part in his ‘disguisement,’ which is nevertheless adequate. It consists in a close imitation of the beautifully blended tints of quiet water amidst luxuriant vegetation. The soft purple breast and sides picture that part of the pool which is shaded from the sky, and reflects almost nothing; the bright-blue wing depicts the water which reflects the sky, and the green and olive back, gi into which the wing’s color softly blends, is a perfect match for the dim reflec- tions of vegetation at the water’s edge. Thus the Purple Gallinule’s costume seems to be a picture of the entire surface of a little pool among the reeds. It largely lacks obliterative shading, and its pattern is to some extent of the ‘ruptive’ type, the ‘break’ occurring between the dark-purple underside and flanks and the bright-blue wings. This makes the sky reflection seem to stop short, as if against the shadow of a water plant, while the purple pic- tures a darkly and graduatedly shaded portion of the pool. A kindred type of coloration, but one involving true iridescence, occurs on the American Green Herons (Butorides). ‘These birds’ costumes have perhaps even closer affinities with that of the Wood Duck, described in Chapter XI. Both haunt opener places than do the gallinules, not being dependent, as they are, on the shelter of the reedy jungle. In this respect, however, the Wood Duck is in- termediate between the other two, though nearer to the heron. Green Her- ons frequent the reaches of open water, and avoid the reeds; but not being swimmers, they are confined to the shores and shallows, and the trees and bushes over them. Characteristically, then, they are birds of the edges of small inland waters. Accordingly, we find them beautifully equipped with water’s-edge colors and patterns. Their ash-green, delicately iridescent backs picture the surface of still water, faintly shimmering, and covered with a film of floating dust or scum, which blurs reflections. Their necks and heads, - when brown (as in some of the species), match muddy patches on the bank, or mud-holes seen through shallow water, or the interior brownness of the trees and bushes over or beyond the water’s edge, or the brown, leafy ground beneath them. But it is on the herons’ wings that the obliterative picturing reaches its most elaborate development. Their ground-color is a soft, iri- descent, water-green, and this is broidered over with a system of delicate marginal stripes and bands of white and buff. These markings are so ar- ranged that they imitate very closely the look of green-reflecting water rolling in small ripples over golden sand—a most characteristic sight at the borders of streams and ponds. The white marks depict the ripples, and the buff Q2 marks the sand glinting through the moving water. Again, the system of white and golden marks together simulates the flickering sun stripes on the bottom, made by refraction from the ripples. Naturally, the life and realism of these pictures are greatly enhanced by the iridescence of the green ground- color. There are a great many other beautiful cases of this use of iridescence in aid of definite background-picturing, but the above example must suffice us here. One more small detail, however, one more phase of the use of change- able color, must be described. It is one to which I have already alluded, in part, in this and an earlier chapter, namely, the apparent ‘opening of win- dows’ in a dull-colored surface by the application of bright spots and stripes. The brightest iridescent and sheenless changeable colors are often set in spots like jewels in an otherwise dull costume. Common and important in * the case of birds, this type of coloration is even more so in that of butterflies. But these will be considered later, and we are here concerned with birds alone. Many birds, particularly tropical ones, have such gemlike spots in the midst of somber plumage. Often they are surrounded by dead black, or some very dark tone of brown or gray. This encompassing dusky pattern, being usually quite lusterless, is the same in all lights, while the bright spot in its midst flashes and alters with every little shift of light or movement of the bird or the beholder. Therefore it has the look of a hole in a motionless dark obstruction—a glimpse through a somber shadow—beyond which are seen sky vistas or the flickering light and movement of vegetation. Or, again, the bright spots may pass for moving bits of vegetation relieving against a motionless shadow or hole behind them. In either case, the solid form of the bird will be effectually ‘cut to pieces.’ To sum up: changeable colors of all sorts strongly tend to conceal the birds that wear them, and iridescence is extraordinarily potent in this way. Its power is of two kinds, which are, however, practically inseparable in their working. First, it goes far toward annulling the normal lights and shadows, with their color-effects, of the surface on which it is placed; and second, its 93 great and vivid versatility of color and shade almost insures the ‘matching’ of some part of that surface with whatever forms its background. When part of a bird’s surface blends thus with his background, the remainder, in most cases, looks un-bird-like. Tridescence should perhaps be considered second only to obliterative shad- ing as a factor in the disguisement of birds; its universality attests its value. 94 CHAPTER XVII BIRDS, CONTINUED. THE ‘OBLITERATIVE’ POWER OF APPENDAGES. ONE USE OF LONG, BANDED TAILS CONJOINED WITH STREAKED BODIES INCE the simple, organic outlines of an animal’s body tend to reveal it to the eyes of enemies, Nature has resorted to many devices in order to conceal those outlines. Such are various kinds of bold, contrasting patterns, one of whose main effects is to hide the curved, characteristic forms by letting into them, as it were, bays and notches of the background, of arbitrary shape. Appendages are exactly the converse of this. They break the normal con- tours by extending them irregularly outward, so that, figuratively speaking, the animal is pulled out of shape and ‘bridged over’ into its surroundings. ‘“‘Appendages”’ include long tails, abnormally extended wing feathers, scap- ular and other tufts, occipital crests, ‘‘beards,”’ etc., and also fleshy outgrowths such as combs and wattles—in short, all superadded external developments, whether of skin or feathers. Many of these devices must have a remarkable concealing-power. Think for instance of the Mexican Quetzal, or Resplen- dent Trogon (Pharomacrus mocinno), with its enormously long, green, droop- ing tail. How potently delusive to a hawk, flying over a seated trogon, might be this indefinite, smooth extension of its green back into the maze of leafage! Other notable examples are the peacocks and pheasants. In the case of many _pheasants an additional peculiar principle comes into play. Their long tails aré marked with strong transverse bars, of two or more colors and shades, like stripes of alternate light and shadow on dead leaves or earth, which tend to merge the tails into their backgrounds when the birds are still, and thus contribute largely toward their obliteration. (See Fig. 133, Chapter XXVII, p. 238; Fig. 120, and Chapter XXTI, p. 159.) But when such a bird glides for- 95 ward, the bold transverse bars, being extended across the line of motion, make the movement of the tail conspicuous, relatively to that of the longitudinally streaked or finely speckled body ahead of it. By this device the bird’s chances of escape from an enemy are decidedly increased. For the predator’s eye is drawn to marks back of the vital part of his intended victim, which is at the same time rapidly moving forward, hence there is likelihood that he will miss his aim by striking behind, perhaps capturing a tail from which the bird tears itself free and escapes. The practical force of this law of the comparative conspicuousness of transverse and inconspicuousness of lengthwise marks in motion can easily be demonstrated. One should take a ribbon of cloth, or a slender board, and mark half of it (one end) straightly and evenly with lengthwise stripes of several colors (or simple black and white), and the other half with the same colors in transverse bars. Then if the stick or ribbon is drawn smoothly across an opening, through which alone it is seen, its motion will be grossly visible while the banded part is passing, and almost invisible during the passage of the striped half. Motion merely tends to convert lengthwise marks into lines, which have little or no visible activity, and may often seem to be passive streaks on the background of the thing that bears them. Hence the elusive- nessof gliding striped snakes among sticks and grasses, in remarkable contrast to the conspicuous movements of banded snakes. (Of this the reader is to hear more in a later chapter.) A practical artificial test of this effect even simpler than that above described, and almost equally effective, can be made with a white string, part of which has been marked with dark spots, and part left blank. The alternate light and dark spots are equivalent to the bands, and the unspotted part is equivalent to the streaks (being, in fact, a single, perfect streak). But the whole proposition is pretty much self-evident, and scarcely calls for demonstration. As a factor in the protection of birds and other animals the principle is of decided importance, and it very likely plays a much larger part than we yet know. Among snakes and long-tailed birds, particularly pheasants, its use is certainly both general and pronounced. On 96 the other hand, the application of such a principle in Nature is almost always enmeshed and interwoven with that of other principles, and this case is no exception to the rule. The same marks which serve to direct an enemy’s at- tention to the tail when the bird is in motion, also serve, as we have seen, to picture the quiet background when the bird is still. Here, however, we have not the blurring counter-action of two principles, but their full codrdinate development and perfect interadjustment. The marks on the bird’s tail may be, and often are, beautiful pictures of leaves and sticks and light and shadow, as potently obliterative as any other picture-patterns; this is their function when the bird is “lying close.” But the moment he moves they are changed into effective ‘target marks.’ The transformation is instantaneous and com- plete; the picture-effect wholly ceases; for leaves and sticks and lights and shadows are never seen to move off suddenly and rapidly over the ground, in a compact, unchanging company. With patterns of lengthwise streaks, on the contrary, there is little visible change between rest and motion, as we have already seen. The longer and straighter are the streaks, the smaller is the visible effect of their lengthwise motion, and vice versa. (The two extreme types are of course connected by all manner of intermediates.) Enormously developed feather-appendages are characteristic of several groups of tropical birds, notably the Birds of Paradise (Paradiseide). Hith- erto, it has always been supposed that male birds of paradise represented the very acme of avian conspicuousness; but this belief is curiously wide of the mark. Ina museum exhibition box, amid blank walls, one of these richly- colored and sumptuously plumed birds is extremely showy and conspicuous; but why should we infer from this that he must also be conspicuous in life in his native woods? They are not monochrome and blank, but, on the con- trary, full to overflowing with every possible variation of form and color, produced by the redundant richness of the vegetation, and the numberless vivid and changeable effects of sun and shade. The eye finds it hard or im- possible to unravel such a luxuriant labyrinth, to separate and define the boundaries of its individual components. Leaves and stems and trunks and 97 branches, vines, fruits, and flowers, shade and sunlight—all mix and overlap and intertwine in the most bewildering way. Amidst, against, this intricate tangle, even a simple bird-shaped bird, of uniform color, would be very incon- spicuous; while a bird (like some of these birds of paradise) so adorned with grotesque plumes * and bristling, ‘hay-stack’ tufts of superadded feathers as to have lost almost all semblance of his simple bodily form, would be almost insured against detection as he sat or moved in such a forest maze. His many- colored plumose excrescences would serve with extraordinary efficiency to blend him into his surroundings—here seeming to coalesce with a bunch of gaudy flowers in sunlight, here with shining leaves, and there with a gulf of somber shade. Then, too, all irregular outward extension of a bird’s form, amid such surroundings, increases the frequency with which parts of his out- line come into actual touch with like or kindred colored details of vegetation, thus obscuring still more potently the bird’s real shape. (See Plate VI.) The three main obliterative agents other than counter shading, which we have now considered, namely, ‘ruptive’ patterns of boldly contrasting patches of color, iridescence and other changeable color, and appendages, different as they are in form, are yet closely akin to one another in the results they achieve. In one degree or another, in one or another manner, they mask the contour of their wearer, and ‘break him up’ into his background and sur- roundings. Kindred in character, the three principles are often combined in application, two or even all three of them frequently occurring in the same costume; and the intricacies of their coadjustment are often very. hard to an- alyze. In the case of certain birds of paradise, all three principles are found in full codrdinate development. Male birds of paradise are well known to have remarkable habits of raising and vibrating their plumes, as they sit in small companies, among the females, in certain chosen trees. The observa- tion of this habit has led people, most naturally, to believe that sexual dis- play is the sole or at least the paramount use of the plumes and gaudy colors. * Some of the big tufts of plumes terminate in such a filmy, hazy spray, that they can scarcely fail, in any view, to seem softly blended into their background. 98 But the assumption that their use is limited to this one function is based on the strangely mistaken notion that such birds are conspicuous in their native woods. The error has been wholly based on theorizing—collectors have not found the birds easy to see in their home forests, but, on the contrary, have often testified to the strange illusiveness of certain very gaudy-kinds, even relatively to their dull-colored and plumeless females. This has led to the belief that they are conscious of being perilously gaudy, and are therefore wary, and careful to keep themselves concealed amidst foliage, etc.—which is evidently a complete misinterpretation of the case. The question of how large a share, if any, sexual display has had in de- veloping birds’ brilliant colors and elaborate appendages cannot be discussed here. But we have at least shown that such developments, far from making birds conspicuous, are all—pied-patterns, iridescence, and appendages—po- tent factors in the concealment of their wearers. Even the lesser appendages, such as small occipital crests, ear-tufts, wattles, etc., all tend to conceal birds by breaking their normal contours. 99 : CHAPTER XVIII BIRDS, CONTINUED. MISCELLANY. MIMICRY AMONG BIRDS. THE BRILLIANT, FLOWERLIKE COLORATION OF HUMMINGBIRDS’ HEADS NOT MIMETIC. SEXUAL DIFFERENCES OF COLORATION WO kinds of ‘Mimicry’ have been described by various authors as oc- curring among birds; first, the form distinguished as ‘‘ Protective Re- semblance,” in which a live animal counterfeits the appearance of an inani- mate thing, and second, so-called Mimicry proper, in which one animal counterfeits the appearance of another. But of Mimicry proper among birds few instances have been cited, while Protective Resemblance has been supposed to cover most branches of avian (as well as mammalian, insectile, etc.) protective coloration, including the many which we have already shown to belong to the very different principle of obliterative coloration. The ques- tion of “protective resemblance,”’ : mate things—is somewhat closely involved with certain phases of the oblit- erative coloration of birds, and must be considered here. I have mentioned it several times in the preceding chapters, in connection, for instance, with bitterns, goatsuckers, ruffed grouse and screech owls. In all these cases, the principle has either been dismissed as having no true application, or has been shown to be subordinate to the laws of obliterative coloration. The ruffed grouse and the screech owl draw their feathers tightly to the body, making themselves as thin and sticklike as possible—and this might be called mimicry. But, as I have explained, this very action is essential to the indeed—the mimicry by animate of inani- perfecting of their exquisite picture-patterns, which imitate the details of their more or less distant backgrounds, rather than the markings on a single fore- ground branch or stub. ‘The bittern, likewise, with head and neck held stiffly upright, might be supposed to be mimicking a stick, but a more critical in- 100 spection reveals the fact that his head and neck picture several reed stems, with their shadows, and that the peculiar attitude is necessary for the most effective display of this obliterative or at most semi-mimetic pattern. (Semi- mimetic, inasmuch as the several reeds seem to occupy about the space really filled by the bittern’s neck, although the effect is still of the neck’s dissolution into its general background and surroundings.) But in all or most such cases, in spite of the evident paramount importance of the obliterative function, it is undeniable that the mimetic effect is sometimes achieved, to a greater or less extent, and hence that it must be a factor in the development of the peculiar actions and even the particular coloration of certain birds. Just how large or how small a factor, who shall say (?); but recognizing the dominant impor- tance of the obliterative laws even in these few special cases, one cannot sup- pose that the other principle has more than a very limited and slender scope. Nevertheless, it is not to be ignored. A Ruffed Grouse picking buds high up among the leafless twigs of winter trees, must often be seen in a light and against a background (as of blank snow) which does not favor its obliterative coloration. Then the extraordinarily slender, stick-like form (accentuated by peculiar angles in the head and neck, and by the erected occipital crest) which the bird assumes the moment it is alarmed, does certainly render it good ser- vice in the direction of protective ‘mimicry.’ At such times the bird’s ene- mies must often mistake him for a knotted branch. Yet, on the other hand, even at such times, thanks to the bird’s perfect obliterative shading and pat- tern, the chance is great that he will not be seen at all (as a solid object), and this chance is probably still of paramount importance. But there is one bird at least in whose case the balance of importance may tip toward the mimetic function of specialized perching-habits. This is the big woodland goatsucker of northern South America, etc., the ‘“Poor-me- ” of Trinidad negroes (Nyctibius jamaicensis), whose characteristic perching place, both by day and night, is the top of a broken stump or up- right branch. Here it sits almost erect, and motionless, with its long and ample tail pressed flat against the side of its perch, which seems to be con- IOI one tinued upward by the bird’s dark, obscurely mottled body, terminating in the broad, flat head. This mimetic attitude is completely effective in the twi- light or moonlight, when the ‘‘ Poor-me-one” uses a stump-top as a look-out perch, whence it launches forth on short flights after aérial insects, soon sailing back to cap the same or sometimes a neighboring stub. There can be no doubt as to the completeness and importance of the mimetic function of the ‘“‘Poor-me-one’s” peculiar perching-habits. The mimicry, however, is mainly positional, or attitudinal, for it is not supported by any very particular developments of the bird’s form or markings. The bird’s mottled pattern, to be sure, is less exquisitely fine than that of many nearly related goatsuckers, and hence less well fitted to serve the full obliterative function of background- picturing, while it must greatly help the stump-top mimicry, especially in a dim light. ‘‘Poor-me-ones”’ have been found roosting in the daytime on the tops of stumps, in the characteristic erect attitude, and in these cases they were certainly “‘making a bid” for mimicry, in which both color and mark- ings played a part. But it is likely that their roosting-habits vary somewhat, as I know that their nocturnal perching habits do. They have a strong pref- erence for naked stumps, but I have more than once seen them sitting in the moonlight on horizontal leafy boughs, and even perching lightly among the slenderest twigs at the very tips of the branches. Assuming that there is equal irregularity in their diurnal roosting habits, as we may pretty safely do, it follows that they must often be so situated that the obliterative function of their coloration comes fully into play. Indeed, there can be no doubt of this, as they are equipped with a complete, though slight, obliterative shading, which hinders rather than helps the mimetic effect; and their markings, though relatively somewhat crude, yet partake largely of all the elements of back- ground-picturing. But, from all that we yet know of the habits of this in- teresting bird, it seems probable that it profits at least as much by out-and- out mimicry (in effect) as by obliteration. This is the most pronounced case of the kind that we happen to know of. Others equally remarkable exist, no doubt; but they are rare enough to be fairly called anomalous. On the 102 other hand, the cases are many of the occasional mimetic aspect of birds whose main protective equipment is purely obliterative, like the ruffed grouse, screech owl, etc., just referred to, and the terrestrial goatsuckers mentioned in an earlier chapter. Other slight and dubious encroachments of mimicry into the domain of obliterative coloration have been mentioned here and there in the foregoing pages, as for instance in connection with the flowerlike bills and frontal appendages of certain water birds (Chapter XV). The gorgeous “‘beauty spots” of hummingbirds, most commonly occurring on the head and throat, are certainly not mimetic, though they have some- times been considered so. Flowerlike though many of these brilliant head- dresses are, there is not, I believe, one among them all which really imitates a single flower, in minute and near detail. On the contrary, they are all flashing pictures of flowery and leafy landscape, at uncertain distances. Hum- mingbirds’ metallic colors mark the very climax of the development of iri- descence, the high obliterative power of which principle has already been ex- plained. Their changeableness often ranges from dull, velvety soot-color to the intensest gleaming of pure red, blue, green, orange or purple, as the case may be; and sometimes several of these bright colors coexist in the same feathers, showing either separately, in different lights, or intermixed, in one light. But the change from one bright color to another is less characteristic of hummingbirds’ iridescence than the change from dull black to keenest brightness. It is in the fullness of this change, and the extreme brilliancy of the high-light tints, that the supremacy of their coloration lies. Perhaps, after all, they do not quite deserve the palm for iridescence, in the strict sense of the word, but for changeable and luminously brilliant color, they are almost unique among animals. Indeed, they have an almost unrivaled obliterative equipment. Behind the dazzling, scintillating blaze of its jeweled head, how can the little round body of a hummingbird be seen? ‘That shifty blaze of red or green or purple light, one instant partly clouded over, and in the next flashing out into the sharpest sunlike sparkles, completely eclipses and masks the form and solidity of the body, now veiling it, and now piercing it, so to 103 speak, with all manner of rents, and vistas of its brilliant, sunlit background, utterly bewildering to the beholder. It is a noteworthy fact, and an interesting theme for study, that the bright colors of almost all hummingbirds are only revealed, or at least Only revealed in their full power, when the birds are seen head-on and facing into the light. This is true, indeed, with many other birds of changeable color, but in no other group is it nearly so marked as among the hummingbirds. Many of their brightest “‘beauty spots” are dead and dusky except in full front view and lighting. This fact has an interesting bearing on the question of the special uses of hummingbirds’ glorious plumage, and suggests several addi- tional possibilities. One of these is that their obliterative coloring is ad- dressed primarily to insects on the flowers and leaves before which they hover, and is therefore offensive rather than defensive. Hummingbirds are so small and lightning-swift that it must be nearly impossible for any predatory birds or beasts to catch them. ‘Tree lizards and small hawks may occasionally seize them while they are perching, although they usually (?) sit on bare, isolated twigs, and are extremely watchful. This watchfulness, however, seems to be directed mainly against other members of their kind (i. e., other hummingbirds, of whatever species), and is aggressive rather than defensive. They are, as is well known, extraordinarily pugnacious, and where several congregate they are continually chasing one another. Nor is this strange — animosity exercised solely against their own kindred; with equal frenzy they dart at flycatchers, hawks, eagles,—any flying bird, either big or small, that enters their domain. On the whole, it must be assumed that they enjoy a comparative freedom from the dangers that beset most of the smaller birds. Yet their obliterative equipment is among the finest, and must be of great im- portance to them. The effulgent, steely brightness of their head-colors, often extended outward by erectile tufts and crests, and showing only in full front view, undoubtedly serves to ‘veil’ them from the sight of insects lurking in and upon leaves and flowers. Without such adornment, the birds would loom up darkly solid between their little victims and the light, thus warning 104 them and giving them a moment’s grace for taking flight or crawling out of reach. But their marvelous headgear masks their menacing solid forms. Irradiated, as it often is, by sunlight, it matches the bright, gaudy back- ground of flowers, leaves and sky, piercing and obliterating the interposed bird-bodies. As, from moment to moment, the bright real scene beyond flashes and twinkles and changes, so the mock scene on the hummingbird’s front sparkles and shifts with his every slightest movement, and every flicker of the light that vivifies it.* It is needless to discuss here the meaning of hummingbirds’ many re- markable appendages, inasmuch as the high obliterative value of such de- velopments in general has already been explained. Male and female hummingbirds are usually unlike in plumage, and their differences correspond to those of most other forest birds. Furthermore, they are in close and evident accord with the differences in the habits of the sexes. The female sits on her neat, moss-trimmed nest, in a shady place, while her mate is buzzing around among the flowers and sunbeams. The bodies, even of the males, are usually equipped with obliterative shading, and the females almost always have it in full development. They are dim in color, relatively to their mates, being mainly soft (but often metallic) green, brown, or gray, and rarely having any fully developed gemlike spots or plumes,—all of which * A probable minor function of this flashing headgear, under the very same conditions, is the illumination, by reflected light, of the calyxes of flowers, and the shaded sides of leaves, which the hovering hummers probe and search. They carry, as it were, little colored lanterns on their heads, whose disk of blue or green or red or purple light can be thrown deep into a tubular flower, or moved up and down and back and forth across a dusky leaf. When any of the very bright ones among these gaudy little ‘reflectors’ are played on by bright sunlight, and headed more or less directly sunward, they cast a really illuminating glow, which can scarcely fail to be of service to the hummers in their insect-hunting. Again, it is likely that the flaming head-dresses of these little birds—as also the erec- tile crests of flycatchers—sometimes act as “‘war paint.” When a male hummer leaves his hovering and perching amidst flowers, where his colors are potently obliterative, and launches forth into free air, often above the tree-tops, in violent pursuit of another bird, his fiery-flashing brilliance may well codperate with the arrowy vehemence of his attack in frightening the object of his anger. Far oftener, however, it must tend rather to dazzle and stupefy the persecuted bird, and, by its incessantly varied gleaming, to bewilder him as to the exact position of the chaser. 105 is in evident harmony with their habits. For, as with other female birds, one of the most critical periods of their lives is the time of brooding, when, hour after hour and day after day, they have to sit on top of their open nests, in quiet, steady-lighted nooks. Even when, as is usually the case, the females as well as the males feed in the gay, sunlit upper border of the forest, they descend into the shady underworld to nest. Hence the fitness of their being softly colored and delicately counter shaded, while their mates are adorned with magnificent jewel-spots and strange appendages. In this matter hum- mingbirds will serve to exemplify the whole group of forest birds in which the sexes are decidedly unlike. The female, almost without exception, is colored and shaded in the way which best conceals her while she is brooding; whereas the male is colored for active life among the leaves and flowers. Corresponding sexual differences of habits and plumage occur among other than woodland birds. Those of ducks I have already mentioned. 106 PLATE Vi AHOEN (CO. BALTIMORT. . eee a Si0m qr se ‘wUIOy 8 pug ou Spores Supybeve-mnoqton jo IA FHLVTd JO NOMLVNV1dXa “oyenoyps qeyy ti fqureu ‘MOUs spolqo re eoueysIp bana < ena “syenoui sy] SuLMoys ‘Buoy *spoom aulde oy} ‘axe ‘taaogaour ‘soutnyd hoke z ordoxy ur aueos ‘yeordéy @ jo $940U-I0[00 ayy Jo Ayfoum epeut amo—anriysoo oaTyBIO}TTqO ayeuIUMsUO: Set 004 ‘esrpertg Jo palg ou} yeq} ‘BoyMoys $y]asJET 9UEDS 4SOI0J gjoYs. Oy} “TepUsL 07 ‘Buyguvrre01 arqeyms a ‘paaaas 3 aaBYy S9}OU-10}OO IMOZ 8,PsIq sy} vartgord sokeyl 'H *¥ pur ees ‘ata Aq yoreyg ‘ISUUOH. AHL NI ASIAVAVd JO SauTa “LH "V—"joajzed sy sui9ys-2019 pue ‘smopeys-oory ‘bus yTTUNs Jo UOT -equasaider $,hep otf uOENTS & YoNs UT “MOUS JAA0 $801} O1Bq SUOUTE s100P Jo NO psovid skep ong paynys jo Apnys y saekeyl ‘H Woqqy Aq ‘si0opyno 'piiq poeynys e wiody peyoz94S ee “ae SY wm gad ‘MHLNIM NI SAVE ANTE CHAPTER XIX BIRDS, CONCLUDED. VARIOUSLY INVOLVED PRINCIPLES OF PROTECTIVE COL- ORATION OF THE BIRDS OF TROPICAL FORESTS. WINTER BIRDS OF THE SNOWY NORTH. CONCLUDING REMARKS ON BIRDS HE dim, brown underworld of tropical forests is tenanted by a race of birds and beasts which show a wonderful uniformity in coloration and degree of counter shading. The daylight in these solemn depths is diffuse and weak; hence the animals which live in them are as a rule very slightly shaded from dark to light, and many have pale-brown undersides. Brown is their prevailing color, and there is one particular tone of rich chestnut-brown which occurs almost unvaried on many hundred species. Such sameness of coloration is remarkable; but it is in perfect keeping with the monotony of the realm in which the creatures live. Almost nowhere else can one find such a wide- ly extended prevalence, throughout the year, of a particular degree of light and a few simple tones of color, as exists inside the shell of the great tropical forests. On the outside of that shell everything is different. There, in the blazing sunshine toward which the closely crowded trees and vines are ever struggling, the victors heave their leafy heads, flashing and dancing with a thousand tints of gold and green and sky-reflected blue—jeweled with gorgeous fruits and flow- ers. In this gay realm of scintillating lights and colors live almost all the bril- liant birds and butterflies, for which the tropics are famous; and they are as closely fitted to their environment in colors and patterns as are their dull-brown relatives of the somber shades below. The tropics are as rich in dull-colored birds and butterflies as in bright ones; but the dull kinds are not often collected and exported except by naturalists, and do not attract popular attention. The transition from the tree-top to the ground type, in habits and in col- oration, is beautifully gradual and consistent. Blue—clear, skyey blue— 107 plays a large part in the costumes of the true tree-top perchers. (Vide, in our northern American fauna, the Indigo Bunting and the Bluebird.) With it are combined red, green, yellow, and all the other bright colors, in sharp ruptive patches, picturing, in general, the sunlit forest crown seen from above. One step below these ‘perchers in air’ live the skulking tree-top birds, as it were the rails and gallinules of the forest’s crown. These live among and beneath the outermost leaves, immersed in a deep bath of green light; and many, though not all of them, are mainly or wholly green. Such, preéminently, are the parrots, those queer and splendid geniuses of the tropic woods. They crawl about through the forest’s crown, and comparatively seldom sit on bare, high perches. When they do so they are of course inconspicuous enough against the tree-tops; but many of them lack the finer developments of sky- matching and more generalized background-matching costume. Instead they are attired to match the leaves and flowers among which they are feed- ing. ‘They are obliteratively shaded, almost all of them, but faintly, in keep- ing with the diffuseness of their usual leaf-dimmed illumination, and their acrobatic feeding-habits, which put them into all sorts of irregular positions relative to the sky-light. There is almost certainly a significant connection, too, between their habit of feeding head-downward, and their gayly blossom- colored tails. Poked up above the feeding parrot’s line of watchfulness, and often into the stratum of gaudy flowers and fruits, this tail must have the best possible disguise if its owner is not to be pounced upon from above by some swift hawk. So it is done out into brilliantly disruptive and oblitera- tive spots and patches of rich flower- and fruit- and sky- and sunlit- foliage- colors,—‘‘conspicuously ornamented,” as people used to say. In fact, it is doubtless, under the normal, appropriate conditions, a very mask of masks. Fitly colored for inconspicuousness above the ‘green-bath’ region, it is scarcely less so for the midmost recesses of that region itself, because the all- suffusing greenness greatly dims the brightest contrasting hues, bringing the red, yellow or purple patches of a gaudy-motley bird nearly or quite into unison with the variations of interior vegetation colors. Thus it is not strange 108 that some of the typically ‘skulking’ tree-top haunters of the tropics are most gaudily ‘patched,’ more so even than the parrots, and that many of the brightest colored ‘high-perchers’ spend much time fairly amid the foli- age. But pure leaf-green is the prevailing color of the tree-top foliage haunt- ers, just as rich brown is that of the forest ground birds. Between these two types again there are perfect intermediates. Such is the motmot, with its ground-brown underside, its soft green back, and its black and bright-blue head; such also is the beautiful jacamar, described in Chapter XVI (p. go), and such are some of the dim-colored, low-ranging hummingbirds. The toucans, also, with their great amount of sharply defined black, are best fitted for obliteration in the intermediate woodland realms, where darkly shadowed big branches and tree trunks contrast with sun-spots and gay vis- tas. But they are also tree-top birds, high-perchers, and their vividly patched costumes of course stand them in good stead in these situations also, in spite of the redundant black. This usually covers the head, back, wings and tail; while the underside is marked with big patches of bright color—red, orange, yellow, white—sometimes all four together—more or less blended into one another, but ending sharply against the black. The huge but almost weightless bill also is brilliantly adorned with yellow, white, or flaming orange, in bold bands and stripes, and the naked skin around the eye is usually bright colored—blue-purple, peacock-blue, or green. Truly, toucans are gorgeous birds! But it by no means follows that they are conspicuous in their native woods! Not even though they are vociferous and active, and often alight on exposed tree-top perches. Here or lower down in the forest; their gaudy ‘ruptive’ patterns ‘break them all to pieces,’ and though the predator at whose approach they ‘freeze’ into rigid stillness may espy the black piece, or the red piece, or the yellow or the blue piece, he is still far from sure to recognize his quarry, for none of these pieces has the form of a bird. So with the colors of the tanagers, the birds of paradise, the macaws, and all the rest of the brilliantly pied tropical forest birds, many of which range, like the toucans, from the upper border of the forest underworld to 109 the airy tree-tops. The frequent black in their costumes, though it often fits in very well with their tree-top background-picturing and ‘ruptive’ pat- terns, seems on the whole to be a concession to the time they spend among dark trunks and branches fairly within the forest. Practically all these party- colored tropical birds have counter shading, in the main relations of their colors, however much its smooth gradation is broken and interrupted by the bold patterns, and however irregular and acrobatic may be their feeding- postures. The multiplicity and variety of bright-colored vegetable forms in the sunlit crown of a tropical forest make a great variety of ‘ruptive’ pat- terns and colors effective for the disguisement of its birds. As has been told in an earlier chapter, ruptive patterns are often intricately commingled both with iridescence and with appendages, all three factors working toward the one end, ‘obliteration.’ It is in the tropics,—in the tree-tops and in the forest- borders—that we find the highest development of all three principles, both separate and combined. Iridescence is not second in importance to ruptive pattern, nor is it less widely and variously used. Appendages also play a very important part, as we have shown. One more component principle of ‘ruptive’ coloration, prominent in the costumes of tropical wood-birds, must be here explained. This is the fre- quent juxtaposition of complementary colors. Just as brilliant iridescence tends to range from one color to its full opposite, or ‘‘complementary”’—as from red to green—so, when two bright colors occur side by side in a ruptive pattern, they are usually not kindred, but complementary. Thus we find green-breasted trogons with red bellies, purplish-blue-breasted trogons with orange bellies, orange-yellow tanagers with steel-purple backs, and so on. Not only are the colors thus placed intensified by mutual contrast, but, by the very added sharpness of their difference, the ‘disruptive’ effect is heightened. The opposed patches seem less than ever to belong to one and the same ob- ject. A bright color tends even to create its complementary.* Look at a rich yellow flower, or some other small yellow object, against white paper. * See the footnote on p. 19, Chapter I. IIO ‘The white next the yellow seems to glow with purple, yellow’s opposite. By the same token, two actual complementary colors side by side are much more powerfully brilliant than two kindred ones so placed. ‘This law has yet other bearings on our present subject. It tends to explain the otherwise somewhat anomalous bright red of certain strictly foliage-haunting birds, like the sev- eral tanagers and trogons. How can such birds, living almost always among green leaves, in a bath of green light, profit by wearing the most vivid red, the diametric opposite of foliage-color? The answer, im part, is this: dimmed by the strong bath of green light, the bird’s red, actually brilliant, looks barely brighter than many of the glowing brown interstices, the paler shadows on dead leaves, twigs and tree trunks amidst the verdant foliage. Even brown dead leaves most favorably situated for showing off their color amidst live foli- age are brighter than bright-red tanagers or trogons least favorably situated for display against a like background. Also, there are, commonly, many dis- eased leaves amid the foliage with red as bright as the birds’. But there is no denying the fact that some of these birds, for instance the northern Scarlet Tanager, are more conspicuous in the green woods than their foliage-colored kindred. On the other hand, again, it is true that bright, strongly contrasted hues, and red among the rest, well serve to produce ‘ruptive’ effects in the color-neutralizing, deeply green-steeped light of the leafy labyrinth in which such birds live, where dimmer tints could not hold their own. This is the way with the beautiful red-and-green trogons, which are by no means easy to dis- cover in their native woods, though vociferous and tame. In tropical as in temperate woodlands, however, the smaller gleaning birds and flycatchers of the shaded lower leafage are characteristically green and yellow and olive, without very bold markings. They live fairly hidden amidst shaded foliage, so that dim leaves in a near view, undiversified by other landscape-details, form their normal background. In his admirable paper on the birds of Trinidad. at the mouth of the Orinoco River,* Mr. F. M. Chapman, the American nat- * “On the Birds of the Island of Trinidad,” Bulletin of the American Museum of Natural His- tory, vol. vi, 1894. ITI uralist, has two pages of very interesting discourse on the color relation be- tween birds and their surroundings in the wild-woods of that island. He fully saw and described the distinctness of the three main color-classes of trop- ical forest birds, the brown, the green, and the gaudy-motley, each with its own appropriate local habitat. Much of what I have said on this immediate theme is scarcely more than an echo of Mr. Chapman’s words, though based on our own subsequent investigations in the same island forests. Limited as they are in extent, the primeval woods of Trinidad are doubtless fairly repre- sentative in character of the great South American tropical forests, and, by the same token, of all the humid tropical forests of the world. For, as we learn from traveled naturalists, tropical ‘‘high woods” are all much alike in their main general characteristics. Just how largely this likeness extends to the general habits and disguising-equipments of the forest birds, we, person- ally, cannot say; but there is every reason to suppose that the main principles are the same among the birds of tropical Asia, Africa, and Malaysia, as among those of tropical America. Indeed, a study of tropical birds in museums, and of the writings of naturalist travelers, leaves one with little doubt on this score. . In the matter of local habitat, Chapman divides the forest birds of Trinidad (and hence of all tropical America) into five groups, namely, those of the tree-tops, those of the shaded foliage below the tree-tops, those of the tree trunks below the foliage, those of the bushes and scrub at the for- est’s border, and those of the ground. The first and second groups comprise respectively the gaudy and the green birds, as has been told. The three remaining groups Chapman lumps as brown birds. This will do for a very general classification, but it seems to me that while the scansorial and ter- restrial species may well be classed together, the scrub birds should be sep- arated from them. For, many of these scrub-birds, as Chapman intimates, lack the characteristic forest brown, or have in addition a large share of other colors. Their ‘class,’ however, is laxer and more irregular than the rest, and its special characters are harder to define. Both in habits and in colora- 112 tion, its species grade into other classes, not only of forest birds, but of the birds of the open land, the reed swamps, bush swamps, and river banks, where still other systems of coloration come into play. Thus there are ‘brush- birds’ which have also a liking for spots of bare, open ground, and have ac- quired markings much like those of larks and other field birds of the North. Characteristically, however, they are somewhat boldly mottled, with much black and white and ash color; ‘pictures’ (to be seen in the dim light of the in- teriors of bushes) of sky vistas overlaced with obstructing, shadowed leaves and branches. Some of those which frequent river banks, like certain Ant- birds of South America, are often marked with the water-shine punctations described in Chapter XI, on a ground-color of muddy gray or brown, oblit- eratively shaded. But the vagaries of this none too sharply defined class cannot be described in detail here. The species which constitute it are less typically birds of the forest than of the brush-lands outside the forest. Nor are they, as a color-class, peculiarly characteristic of the tropics, being scarcely separable from the brush-birds of temperate climes. True, the brown, green and gaudy classes are also represented in northern woodlands, but by no means in such full and special development as they have attained in the teem- ing tropics. In the snowy northern winter, on the other hand, where the avifauna is extremely meager, we see special color-adaptation reduced to its simplest terms. The costumes of the few birds which pass the winter in the snowy northern: forests, deciduous or evergreen, are, it is evident, specially fitted to that season of the year. Some of these birds even, like several of the boreal “mammals, turn white at the approach of winter, resuming their gray or brown mottled plumage in the spring. Such are the ptarmigans, described in Chap- ter VII. But most of the species either keep the same coloration throughout the year, or merely become somewhat paler and dimmer in the autumn, grad- ually brightening, by the erosion of the feather-tips, through the winter and spring. But even those which do not change color are best equipped for con- cealment in the winter—the dangerous time of leafless woods and keenly 113 hungry birds and beasts of prey. One of the most patent signs of this is the great prevalence of white in their costumes. The Snowy Owl, for instance, the chief rapacious bird of the high north, is white (more or less profusely flecked or barred with sooty brown) throughout the year. During the few weeks of arctic summer, when it hunts and nests on mossy, treeless tundras or barrens, it must be a conspicuous ‘object when seen from above against the ground (although even then it may often be mistaken for a scrap of lin- gering snow or ice). But it has little or nothing to fear from predaceous enemies, and its summer diet consists chiefly of lemmings and other small mammals which live on the open ground, so that the owl always appears above them, against the sky; hence white serves it as it serves the seafaring terns and gulls (Chapter XII) and the partly white-masked mammals to be described in a later chapter. Another northern bird, colored almost exactly like the Snowy Owl, and with kindred habits, is the White Gerfal- con. In addition to these more or less predominantly white birds (ptar- migans, owls, and falcons), many of the smaller species of the winter North are largely marked with white (irrespective of their obliterative white under- sides). Noteworthy among these are the woodpeckers, titmice, some of the Fringillide, and two or three of the Corvide (namely, the magpies and the North American Blue Jay). Most of them wear a pied or boldly speckled pattern of black and white, which reaches its highest development on some of the woodpeckers, as the Hairy and Downy (Dryobates villosus and D. pubescens) of America, and the Great-spotted and White-backed (Picus major and P. leuconotus) of Europe. These woodpeckers are in fact cov- ered with adequate generalized pictures of bits of winter landscape, where dark tree trunks and branches relieve against the snow or sky. Fig. 83 (photographed from a picture made by combining a real Hairy Woodpecker’s skin with a painting of a winter-forest landscape) will tell the reader more than many words. Even in summer, though less wonderfully fitted to the land- scape, these woodpeckers are far from being conspicuous birds. The larger outstanding spots of white still often pass for glints of sky seen through the 114 Fie, 83. Hairy Woodpecker (Dryobates villosus) in winter woods. [See p. 114, Chap. XIX.] Photograph of a stuffed skin against a painted landscape. Scene copied, ‘tone’ for ‘tone,’ not from the woods, but from the woodpecker. The reader must judge for himself as to its realism. forest, while the smaller ones, and under some conditions the larger ones too, produce a mottled effect much like that of the tree trunks on which the birds climb. (See Chapter VIII, p. 50.) Significant in connection with the evident winter-picturing in the costumes of these northern woodpeckers is the differ- ent coloration of their southern relatives. The Downy and Hairy Wood- peckers are distributed from the southern United States almost to the northern limit of tree-growth, and being non-migratory, have developed certain geo- graphical racial differences. The birds of the northernmost race are biggest and whitest, those of the southernmost, smallest and blackest. Other species of the same genus, and of nearly allied genera, which are peculiar to the southern part of the country, below the limit of snow, lack the larger white blotches, being for the most part closely barred and speckled, in ‘tree-bark patterns.’ The Golden-winged Woodpecker (Colaptes auratus, etc.), which is mainly brown and black and yellow, abounds in the northeastern United States during the summer, but migrates southward in the fall, for the most part keeping outside the snow-line. Looking still farther south, to the Amer- ican tropics, we find the woodpeckers brown and red and yellow and gray and olive, and, with a few exceptions, almost entirely devoid of white. Many of the tropical woodpeckers, indeed, and their allies in habits the Wood Creep- ers (Dendrocolaptide), belong strictly to the class of tropical ‘brown birds’ described earlier in this chapter. The northern tits and nuthatches are colored much like the northern woodpeckers, but in simple, bold, undiversified ‘ruptive’ patterns. (See Fig. 61.) So also-with the magpies, which have the added gift of rich irides- cent color in the tail and wings,—picturing snow-shadows and fir foliage. The costume of the beautiful Blue Jay (Cyanocitta cristata) is a wonderful picture of a winter landscape—snow in shadow, snow in sunlight, sky, trees, and vinous-gray scrub—all are there, in true and exquisite comminglement. Here again we have a picture to show in aid of unconvincing words. The Blue Jay picture in Plate VI, unlike the woodpecker figure, was painted from bird-skins against a real out-door background. Of course the Blue 115 Jay’s costume is not confined to this one kind of background-matching. It pictures, perhaps equally well, a much nearer bit of snowy ground, thickly fretted with blue shadows, with some dark twigs or branches relieving against it. Wherever the bird alights in the winter woods, he looks like a vista through the tree in which he sits to one or another of these blue and snow-bright back- grounds. He bears a full obliterative shading (from dark blue and black to white), without which the delicate distance-picturing would be impossible. In summer the Blue Jay’s perennially unchanged coloration is less closely fitted to its environment; but the bird is never conspicuous. The blue, seen in the leafy sylvan dimness, is usually soft and dull, and not sharply differen- tiated from the vinous ash-color of the breast and flanks; the white spots, as in all such cases, picture glints of sky, or lighter leaf-vistas; while the dark marks look like sticks and twigs and holes and shadows. (See Fig. 60.) Or again, when the clear, light blue of tail or wings gleams out with especial brightness, it may pass either for sky-shine on the leaves or for a bit of blue sky showing between them. Another boreal winter bird, the American Gos- hawk, in adult plumage, wears a beautiful combination of the color of bare twigs and deeply shadowed snow; and the nuthatches also have the same snow- shadow color on their backs. Among the Fringillide, the best example of a white-marked northern bird is the Snow Bunting (Passerina nivalis), common to both continents. Some of the redpoll linnets (Acanthis) have much white in their make-up (though mixed and blended rather than in clean spots). Some of the crossbills, and the pine grosbeaks, also have a share of it. But with most of the northern conivorous and bud-eating jringilline birds, red plays an important part, in the winter as well as in the summer plumage. For what are the chief colors of field and forest landscape in the northern winter? Three of them, black and white and blue, have already been named; what are the others? Soft red, gray (of tree trunks), and dusky green. Vinous ash-color ranging fairly into red is the hue of one large and ubiquitous element of these winter scenes, namely, the outer twigs of all the deciduous trees and bushes, covered with 116 buds. (See Plate VI again.) Except when a wet snowstorm or an icestorm has plastered and veiled these twigs, the average northern landscape in win- ter is full of great masses of soft, purplish red, reaching here and there a brighter tint. Golden brown, varying to red and purple, is also the color of the cones of spruce and pine and fir trees. It is among these pink and bronzy twigs and buds, seed tassels and cones, that the northern grosbeaks, linnets, and crossbills get their food, and the red or reddish colors worn by many of them are therefore in full accord with their environment. So it is also that the red spots on the heads of the males of northern woodpeckers are not dis- cordant notes in their obliterative pattern. Female crossbills and pine grosbeaks are olive-green, olive-yellow and gray—the colors of tree trunks and the foliage of evergreen conifers, and many of the cones themselves. The coloration of some of these birds, notably the Red Crossbills, some- times helps to produce a truly mimetic effect. In conformity with their acro- batic habits of topsy-turvy climbing and feeding, these crossbills have a very scant obliterative shading. In a full, unbroken light their solidity is therefore apt to show, and when they sit or cling on coniferous trees they often look much like cones, by virtue of their similar colors and not dissimilar shape. Once more we must return to the subject of obliterative white markings on birds’ upper sides. The birds that wear them may be grouped as follows: those that live high enough up in trees or bushes so that glints of sky and gleaming foliage-vistas are common factors of their background; those that live on the water or the borders of water, where reflected glints of sky are com- mon; and, last but not least, those which live amid snow. Predatory birds that are mainly white all over, like many sea birds and the Snowy Owl, are, as we have shown, equipped for the greatest possible elusiveness when seen against the luminous sky by animals beneath them. The application of this principle among mammals we shall describe in a later chapter. Its bearing on the coloration of birds alone is large, far larger than one would at first suppose. It is involved, for instance, in such cases as those of the snow- 117 white herons, egrets and swans, whose whiteness tends to efface them against the sky, in the view of their aquatic prey and enemies, as no other color or sys- tem of colors could. Outside of the several classes above named, which means among ground birds and birds of the interior forest gloom, white mark- ings are practically wanting, with the exception of those that belong purely and simply to obliterative shading, and the occasional white tail-spots, dis- played chiefly in flight, which we shall consider in a later chapter. The foregoing nineteen chapters together form an exposition, however fragmentary, of all the main laws of disguising-coloration as applied to birds, in as far as they have yet been discerned by my father. In truth, although we have disclosed much that is new, even in addition to the big general prin- ciples of obliterative shading and picture-patiern, yet the subject is no more than broached. For several reasons we have seen fit to treat of birds in more detail than we shall attempt with other classes of animals. In the first place, birds: are ahead of all other classes, with the doubtful exceptions of fishes and lepidop- terous insects, in the elaborate variety and extreme development of their dis- guising-coloration. (The slender, simple hairs of mammals, for instance, are but a paltry medium for the building up of patterns, relative to the broad, flat and subtile feathers with which birds are covered.) In the second place we, personally, know more about birds than about any other animals. In the third and last place, the main principles of disguising-coloration are the same throughout the animal kingdom, and therefore if one describes them some- what minutely in connection with one representative class, the other classes can be dismissed a great deal more briefly. The next three chapters will deal with mammals. 118 PLATE Vil ANOEN BecO.aint EXPLANATION OF PLATE VII - COTTONTAIL RABBIT. Painted by .Gerald H. Thayer. Background mainly by Emma B. Thayer and A. H, Thayer CHAPTER XX MAMMALS. GENERAL PRINCIPLES OF THEIR DISGUISING-COLORATION. FULL OBLITERATIVE SHADING ALMOST UNIVERSAL AMONG THEM. EXCEPTIONS CONSIDERED LMOST all mammals, from some of the biggest oceanic cetaceans to the smallest terrestrial quadrupeds, are equipped with a full obliterative shading of surface-colors. That is, they are darkest on the back and lightest on the belly, usually with connecting intermediate shades. White is by far the commonest color for the middles of their undersides, while the dark of the upper sides very often culminates in a black or dusky median line, a sort of painted ‘ridge pole,’ laid along the center of the back, over the tips of the dorsal vertebree. With or without such extreme accentuation, complete ob- literative shading characterizes most of the species of almost all the mam- malian orders. This generalization applies to the great order Marsupialia, comprising the kangaroos, opossums, phalangers, the Tasmanian wolf, and many other forms; to the marine order Cetacea (whales, dolphins, porpoises, etc.); to the order Chiroptera, or bats; to the vast order Rodentia, including rats, mice, squirrels, beavers, hares, agoutis, porcupines, etc.; to the order Insectivora (hedgehogs, shrews, moles, etc.); to the order Ungulata (hoofed animals, among which we may here include, for convenience, the elephants and the hyrax, as well as the tapirs, rhinoceroses, and the hippopotami); to the great order Carnivora (containing the cats, from the lion to the lynx, the civets, mongooses, and hyenas; the canine beasts—dogs, wolves, jackals, foxes, etc.; the otters, weasels, raccoons, badgers, bears; the sea lions, wal- ruses and seals); and to the order Primates, including lemurs, monkeys, apes and man. But in all the above-named orders, and notably in Ungulata, Chir- optera, and Primates, there are exceptions to the rule. These exceptions are 119 most significant, since, in almost every case, they accompany some important peculiarity in the animal’s habits or physical characteristics. In the cos- tumes of many bats, for instance, the counter shading is defective, or alto- gether lacking, the fur of the lower surface being almost or quite as dark as that of the upper. But this is in strictest keeping with their habits, for they are nocturnal and volant, flying swiftly, and for the most part feeding on the wing, like goatsuckers, while, unlike goatsuckers, they sleep by day in the pitchy darkness of deep caves and ruins, or in hollow trees, suspended by their hind claws, and hanging head downward, perpendicularly. Hence, it ap- pears, Nature has been very little concerned with giving them disguising coloration. Their perpendicular sleeping-posture in itself precludes the pos- sibility of their benefiting by the regulation obliterative shading while they are at rest. If they are to be counter shaded at all, it must be from tail to head, rather than from back to belly. Traces of such an aberrant shading exist on many species, in the shape of white or yellowish markings on the face,* and a brown paler than that of the rump and belly on the fore-back and fore-breast. This partial counter shading, as well as bats’ prevailing earthy and rock-brown color, serves them in the cases where their roosts are more or less exposed to the daylight. Some kinds, indeed, habitually roost in the open air, under big tropical leaves, under the branches of trees, and on their trunks. The tree-trunk species while roosting are lighted as are scansorial birds, and for obliteration they would have to be counter shaded in the normal way,—as some of them are. But several of these open-air bats are developed for mimicry instead of obliteration. Thus a beautiful little South American species is formed, marked and colored to look like a woody knot or other excrescence on the underside of a mangrove branch, whereto it clings, by day ; not hanging downward, but pressed close against the bark, holding on both with feet and finger-hooks. Usually several are found to- gether, in a neatly distributed little group. Disturbed, they take wing all together, with a tiny, complaining twitter, and fly away like a troop of sand- * See also Chapter XXII, p. 157. I20 pipers; alighting again, daintily and quickly, on the first new branch that suits them,—or sometimes wheeling and returning to their former perch,—and instantly they are changed back into lifeless knots. When a normal obliterative shading does exist on bats, as is the case with a good many species, its main service is probably the making them addition- ally elusive in their crepuscular and nocturnal flights. The shading is usually rather slight, from deep brown to paler grayish, but it sometimes reaches dingy or even pure white. There is no other important order of mammals in which obliterative shad- ing and disguising coloration in general play so small a part. The compara- tively few other beasts whose costumes are notable for their nonconformity with the predominant rules of obliterative coloration, may be grouped as fol- lows: They are either strictly nocturnal (some of the smaller carnivora, and also some beasts which are large and fearless, but only semi-predaceous, e. g., many bears), or fossorial, living almost wholly underground (some edentates and moles), or arboreal, skulking (wont to take refuge in thick coverts and dense shade), and also acrobatic, often standing erect, and thus exposing their un- dersides to full light (e. g., some of the apes and monkeys), or protected by some extraordinary defensive equipment, so that they are in little or no dan- ger from the attacks of predatory creatures (e. g., hedgehogs, porcupines, echidnas, pangolins, and some armadillos), or they enjoy a like security by virtue of their gigantic bigness, and, being herbivorous, have no need of ob- literative coloration to aid them in securing their food (e. g., elephants, rhi- noceroses, and hippopotami). Compared with the vast roll of the species equipped with full obliterative shading, the exceptions contained in these five classes are numerically insignificant. But they are important as bearing further weighty witness to the beautiful completeness of the correlation be- tween animals’ modes of life, defensive and offensive armaments, and dis- guising-coloration. The hedgehogs, porcupines, and echidnas (belonging respectively, in the sequence named, to the orders Insectivora and Rodentia and the order Monotremata of the strange subclass Ornithodelphia) are all I21I equipped with a thick coat of formidable spines, but have no obliterative ‘shading, nor any other pronounced elements of concealing-coloration; whereas their closest relatives which lack the peculiar defensive armaments are all (if we set aside a few fossorial forms) obliteratively colored to the full. The echidna’s sole known ally, Ornithorhynchus paradoxus, the Duck-billed Plat- ypus, has no spiny mantle, but its brown furry covering is obliteratively shaded. So also with the coypou, beaver, and other rodents more or less closely allied to porcupines, and with all the spineless Jmsectivora akin to hedgehogs, with ‘the possible exception of a few of those which live in dark tunnels under- ground, namely, moles'and shrews. But the most strictly fossorial shrews, and even moles, must sometimes come out into the daylight, where they are exposed to the attacks of predaceous birds and beasts; and accordingly we find some degree of obliterative shading in the coats of almost all the species. There may be some kinds which are as dark on the belly as on the back; but not one of the most monochrome-looking species we have examined has proved to be so. Among apes and monkeys, the want of pronounced counter shading is by no Means uncommon, though it does not characterize the majority of speciés. This lack may be fully seen on the big anthropoid, semi-erect apes, the scrawny hair of whose breasts and bellies is as dark as that of their backs. But, thanks to their size and strength and ferocity, these great apes belong in part to the class of ‘immune’ beasts, while they also lack the need of obliterative coloration for offense which the truly rapacious animals have. The Orang- outan of Borneo is described as being the king of its native jungles, dreading only man; and we may well assume that the huge gorilla of central Africa enjoys equal privileges. It might be supposed that whales were sufficiently protected by their colossal size and strength, and that the toothless kinds, which feed on the minute, lowly animal organisms that swarm in the ocean like dust motes in-house air, would have no possible need of any kind of disguising- coloration. Yet almost all of them have a fully developed obliterative shad- I22 ing,* and almost all are subject to dangerous and deadly attacks from smaller marine animals,—such for instance as the Grampus or Killer (Orca gladiator). Sea-cows or manatees, and dugongs (order Sirenia), those uncouth sur- vivors of an ancient race of littoral-marine and fluviatile herbivorous mam- mals, are not pronouncedly equipped with obliterative shading. They are colored like grayish mud and dingy water, however, and tend to be palest underneath. The predatory and semi-predatory land beasts which nearly or quite lack obliterative shading are few in number, and, as has been said, they are chiefly nocturnal.t Almost all belong to the group Arctoidea, or bearlike animals. Good examples are the black and brown bears of Europe and America, the Polar Bears (Ursus maritimus) the Wolverine (Gulo luscus), and several ex- clusively American beasts, the skunks (Mephitis and Conepatus), and the Fisher or Pennant’s Martin (Mustela pennanti). But, though largely without counter shading, some of these animals are obliteratively colored to a high de- gree. The Polar Bear, like the boreal foxes, hares, weasels and ptarmigans in their winter dress, is immaculate white, above and below; and, as has been explained in connection with ptarmigans (Chapter VII), this uniform white- ness is about the nearest approach to perfect obliterative coloration that an inhabitant of realms of glaring snow and ice can have, because there the monotonous, perfect whiteness makes counter shading inadmissible, since it would involve making the beast’s top darker than the surrounding scene.{ The shadowed and therefore too dark underside cannot be light- ened, but neither must the fitly illuminated white back be darkened to match it, for then there would be a monochrome, complete (although flat- seeming) beast-form to silhouette against the background. The skunks, and in less degree the wolverine, are equipped with wonderfully efficient * Those whales which prey, more or less, on forms that have both sight and power of locomotion, must be quite as much helped by obliterative coloration in their approach to such prey, as any of the beautifully counter shaded fishes that hunt in the same waters.—A. H. T. : + The slight counter shading of black nocturnal animals has apparently the exact degree to defeat the very small illumination of night—A. H. T. t See also p. 151. 13% ruptive patterns, of a peculiar sort, whose function will be explained in a later chapter. The other animals above named—brown and black bears and Pennant’s Martin—are all nocturnal. The bears, furthermore, are too big and powerful to need defensive coloration; though, being partially rapa- cious, they do not wholly lack disguising-patterns. (See Chapter XXII.) Thus only the cases of the Fisher and a few other small carnivorous quad- rupeds of like coloration remain in any degree anomalous, while the facts that such beasts are nocturnal, acrobatic, and deep-forest haunting, go far toward clearing up the difficulty. The living members of that strange agglomeration of animals usually grouped by naturalists in the order Edentata, are almost all nocturnal, al- though they show otherwise great diversity of habits. Some are fossorial, some terrestrial; others semi-arboreal; others again, arboreal; and still others ultra-arboreal, being, alone among living mammals, practically incapable of any mode of progression except handing themselves, belly-uppermost, along the undersides of tree-boughs and vines. Of course I refer now to the sloths, Bradypodide. ‘Their protective coloration is probably. mimetic, in part at least, like that of certain bats, already mentioned. To be sure, they are often equipped with a slight inverted counter shading (from darker bellies to lighter backs, as in the case of many of the lepidopterous larve which feed and rest upside down); and their coloration often inclines also toward the ‘ruptive,’ based on bold, arbitrary patchiness. But these equipments are irregular and inconstant, and rarely or never would they appear to be of dominant im- portance. On the other hand, many travelers have commented on the mimetic function of sloths’ queer, weedy-furred coats, aided by their shapelessness and sluggish habits; and such is very probably their chief protection. Hanging, lumplike, up among the complex, tangled forms of branch and leaf and vine and vegetable parasite, their rotundity perhaps revealed by the insufficiency of their counter shading, and at the same time obscured by their irregular, shaggy coats, they may well be hard to detect as animate forms. For they must look very much like masses of moss, withered air-plants, or other vegetable 124 débris, or like parts of moss-draped or ragged-barked boughs or trunks. So travelers have said, and in this case there seems to be no reason to question their interpretation. Sloths vary widely in color, but a rich olive-brown is perhaps the most characteristic tint. Sometimes they are almost green, owing to a growth of minute alge on their fur; and this of course enhances the mimetic effect, allying them in the very ingredients of their superficial structure to the vegetable masses all about them. Again, they are sometimes rather brightly varied with patches of dark brown, blackish, dull orange and yellow, and even white; but these markings barely attain the rank of true ‘ruptive’ patterns. One marking, however, to which they are very prone, is extremely interesting and noteworthy. This is the blackish stripe or spot on the fore-back, sur- rounded by a rim of light color, varying from orange brown to white. Strangely enough, this marking is almost precisely duplicated on the head of a species of sphinx-moth larva (see Plate XV, Fig. T, Chapter XXV) and it there plays an important and unmistakable part in the imitation, beautifully achieved by the aspect of the entire caterpillar, of a pendant, curled-up, brown dead leaf. The larva hangs head downward, and its white-rimmed black spot pictures the shadowed hole at the tip of the pendant leaf-roll. There seems very little room for doubt that a like effect is achieved by the peculiar shoulder-spot of the sloth. Evidently, this simulates a shadowed orifice, with brightly con- trasting outward rim, in the bottom of the vegetable mass mimicked by the entire beast. (See also page 157 of Chapter XXII, and Fig. 120.) The armadillos (Dasypodide), another family of edentates, are terrestrial and fossorial, and almost hairless. But they are partially protected from their enemies by a hard, annulated shell, as well as by their prodigious dig- ging-powers. Some species roll up into almost invulnerable balls, as do their African and Asiatic relatives, the armor-scaled pangolins (Manide). Both these families, besides being chiefly nocturnal, belong perhaps to the group of specially protected animals (although their armament is purely and passively defensive, like that of tortoises, and unlike that of porcupines), and their protective coloration accordingly is meager and irregular. Armadillos 125 are earth- and sand-colored above, and their broad, shelly roof, somewhat counter shaded, extends so far down over the sides as almost wholly to hide the shieldless and more or. less hairy under parts, which, in conformity with the common law, are often decidedly paler in color. It is doubtful, though, whether the ventral paleness has in this case much significance beyond the lax and aborted pigmentation of a surface almost never exposed to view. But armadillos’ heads and tails are always (?) counter shaded. The Myrmecophagide, or American Ant-eaters, are all fully furred, and, despite their nocturnal habits, obliteratively colored. Only three species are known, namely, the Great Ant-eater (Myrmecophaga jubata), the middle- sized Tamandua (Tamandua ietradactyla), and the Little Ant-eater (Cyclo- thurus didactylus). M~yrmecophaga is strictly terrestrial, but does not burrow; Tamandua is chiefly arboreal, and Cyclothurus strictly so, being halfway to the sloths in habits and demeanor. The two larger kinds lack diurnal ob- literative shading, but are equipped with powerful ruptive patterns of black, white and gray.* The exquisite, pale-brown furry coat of the little Cyclo- thurus bears a rather faint obliterative shading, and a blackish ‘secant’ stripe along the underside. The ‘‘Aard-vark”’ of South Africa (family Orycteropodide) represents the only other type of edentate that remains to be considered. It is strictly noc- turnal, fossorial (living in deep burrows), and extremely timid and wary. Its body is scantily clothed with coarse brownish hair, and has in all probability the regular slight ‘nocturnal’ counter shading. (See the second footnote on page 123.) I have already named the general rules which seem to govern these va- rious breaks in the prevalence of full-blown obliterative coloration among mammals. To recapitulate, the exceptions occur, in the first place, among beasts that are habitually or very frequently hidden away from the light, either underground, in caves or hollow trees, in thick vegetation, or in the cloak of night. In the second place, they occur among beasts, mostly non- * See Chapter XXII, p. 149. 126 predaceous, which are almost or quite immune from danger at the hands of their wild fellow-creatures, by virtue either of their great size and strength, or of a potent fixed defensive armament. In the third and last place, a few defenseless arboreal mammals are equipped for mimicry rather than oblit- eration. It is, then, among unarmed, daylight-inhabiting mammals, and among the purely rapacious mammals, both of the plains and of the forest, that ob- literative coloration, based on full and simple obliterative shading, reaches its highest and most uniform development. Many of the terrestrial beasts, particularly those of the open country, are equipped with full counter shading and ‘ground’-color alone, almost or quite without markings. Such are lions, wolves, jackals, kangaroos, hares and rabbits; marmots, some gophers, and several smaller rodents and marsupials; as well as many of the big ungulates or ruminants, such as wild asses, some wild bovines, and many deer and antelopes. It has long been known that the animals of the desert are ex- tremely alike in coloration—insects, reptiles, birds and mammals all sharing the same sandy brown. But codrdinate with this fact is one hitherto ignored, ‘namely, that the colors of these desert animals do as universally and unvary- ingly constitute a perfect obliterative gradation of shades, from dark above to light below. As there is great monotony and uniformity in the animals’ lighting and backgrounds, so is there sameness in their color-tints, in their all-essential obliterative shading, and in their scanty pattern,—when patterns occur, for they are often wholly wanting. Among the simply-colored mam- mals named above, the lion and the jackal may fairly be said to belong to the desert class. Most of the others are more characteristically inhabitants of grassy prairies; while some are partially sylvan. The Cottontail Rabbit (Lepus floridanus transitionalis) shown in Plate VII, at the head of this chap- ter, is a fair type of the fully counter-shaded, plain-colored terrestrial mam- mals.* ‘These paintings of ours (rabbit, Ruffed Grouse, Copperhead Snake, * More strictly, however, this hare is a semi-patterned, semi-sylvan beast, and one in whose normal backgrounds there is a good deal of variation. T2327 caterpillars, etc.) are, we believe, the first ever published which rightly illus- trate and in some respects do justice to the wonderful effects of obliterative coloration, based on the great law of obliterative shading. Many photographs of wild animals in nature (e. g., the ptarmigan shown in Fig. 41) illustrate the same thing with compelling force and beauty. Photography, indeed, is the great ally of those who would expound the laws of obliterative coloration; and it is destined—more swiftly now that the underlying principles of that beautiful phenomenon have been disclosed and analyzed—to effect a funda- mental change in men’s knowledge of the looks of animals in nature; and, by the same token, in the drawings and paintings men make of these wild ani- mals. The world has had enough, or must soon have had enough, of pic- tures of birds and beasts with their light-and-shade falsified to make them show. Outdoor nature as it really is, in the matter of the marvelous and exquisite visual correlations between animal and environment, offers to art, in this late age, an almost boundless virgin field. Figs. 84-89 and 93-04 are all photographs from live mammals, either in nature or captivity. Fig. 86 shows a tame hare upside down against a nor- mal background. (See also the photographed flat hides of mammals shown in Figs. 11, 12, and. 13 of Chapter II.) Mammals, totally unlike birds, butterflies, and even fishes and reptiles, are almost wholly devoid of really gaudy surface-colors. In some few cases, mammalian fur reaches or nearly reaches the standard of pure color in the direction of yellow, green, and possibly orange; but its normal and usual range of tint is through all the grades of neutral, from black to white, and through the entire scale of browns and grays, from vivid rust-color to cold bluish gray. When clear, gaudy color does occur on mammals, it is usually in the naked skin, as on the faces and rumps of certain monkeys and baboons. Now whether, as may well be the case, mammalian hairs are, as compared with the feathers of birds, the scales of butterflies, and the skin and scales of fishes, structurally incapable of producing brilliant colors, there is yet a sufficient ulterior reason why we should expect to find mammals brown and gray, 128 Fig. 84. Wild Cottontail Rabbit (Lepus floridanus transitionalis) in po- sition. ‘Obliter- ated’ by counter- shading and faint ground -picturing pattern, Photographed from life, outdoors. Captive rabbit. Fic. 85. Domestic hare.’ Obliterative shading, etc. Photographed from life. Fic. 86. Domestic hare laid on its back, outdoors, so that the obliterative shading is reversed. Photographed from life. or at least much less brightly colored than birds, etc. The fact that they are so becomes in fact one more strong link in the chain of evidence in proof of the universal and paramount importance of concealing-coloration. Mam- mals (we will exclude the aberrant forms, as the bats—winged, nocturnal, and cavern-haunting—and the marine types) are characteristically flightless, and hence, in a great measure, tied to earth. In the forest, the outermost skyward excursions of the most arboreal species rarely or never take them into the gay regions inhabited by the more brilliant birds and butterflies. For these are masters of that unstable element, the air, and can go whither they please above as well as upon and through the ground and the forest. Hovering, flitting, perching lightly, always ready to resort to their wings in an instant if the perch should fail them, even many of the heavier members of this gifted class—even many of the birds, in short—are wont to pass most of their time in the brilliantly lighted outermost border of the forest, among the very tips of the slenderest twigs, where most of the fruits and flowers grow, but whither even the most agile climbers of all the wingless mammals dare not venture. Metaphorically speaking, birds and butterflies are creatures of the grave and ponderous globe’s exterior efflorescence, of the colored foam at the outermost edge of things, of the borderland between earth and sky; while mammals, man included, are citizens of the sober underworld. Plod- ding, earth-bound things, they walk upon the solid ground, and drive their tunnels in the darkness under it; while some of them ascend its skyward ex- crescences, the trees; but high as they may go they are still the creatures of the ‘underworld,’ and the bright realm of butterflies and birds is still as a rule above them. By their life-laws, they are forever associated in close con- tiguity with things brown and gray and black;—mud, sand, the dead leaves. and twigs of the forest floor, rocks and pebbles, tree trunks and branches— and the black holes and shadows among all these things. Some few of the most arboreal kinds live in the realm of preponderant sylvan greenness (see p. 108 of Chapter XIX), and several of these (small monkeys, etc.) have olive- green or even clear green and sometimes yellow fur. But as no wingless 129 mammals attain, except in rare chance moments, to the bright and efflores- cent ‘borderland,’ the headquarters of the brilliant butterflies and_ birds, so are there practically no really gaudy mammals. Furthermore, it will be found, in almost every case, that the birds most closely akin, in’ways of life and local habitat, to some dull-colored mammal, are themselves dull-colored; for birds are distributed ubiquitously, from their own special realm to the mammals’ stronghold, the solid ground below. (See p. 107 of Chapter: XIX.) Even outside the forest, the characteristic difference between the two classes, in habits and in accompanying coloration, is maintained. Wherever there is vegetation of any sort, down to lowly herbage, there it is the general wont of birds to feed and fly and climb on #op of it, in the light, and amid bright colors, and the general wont of mammals to feed and crawl about below it, amid shadows and dull colors. This generalization applies even to semi-aquatic birds and beasts. Wood Ducks swim high, and often sit on trees; kingfishers sit on stumps and branches above the water; Purple Gal- linules walk about, erect, on lily pads; and all these birds are marked with rich or brilliant water-colors. Otters, muskrats, beavers, capybaras, and other semi-aquatic mammals, swim either under water or almost submerged, showing only a low line of back and head. When they are out of the water they are always close to terra firma—on the muddy shores, in holes, or run- ning about under the bushes and weeds and tree-roots; and no one of these beasts is brightly colored. But here again we find that the bird tribe invades the mammal tribe’s proper realm, and shares its system of dingy colors, though the mammal tribe cannot reciprocate. Thus there are rails and other marsh birds that live like skulking quadrupeds, on the ground below the reeds and bushes, and like them also they lack brilliant colors.* To sum up: on the bare fields and deserts, in the dusky forest shades, and below the taller vegetation in the marshes, there are ‘mammal-colored’ birds; but nowhere are there ‘bird-colored’ mammals. (A statement essentially correct, though for absolute accuracy it would need some qualifying.) * Except on their beaks, legs, etc., in the breeding season. 130 Equally in keeping with mammals’ lack of gay colors and minutely elab- orate patterns is the fact that the great majority of them are nocturnal, hiding by day in hollow trees and holes in the ground. Nevertheless, in addition to a complete general adequacy, based, for the most part, on full and perfect counter shading, mammalian concealing-costume presents many beautiful types of generalized obliterative picture-pattern. Some of these are the sub- jects of our next two chapters. 131 CHAPTER XXI MAMMALS, CONTINUED. MARKINGS OF COUNTER-SHADED MAMMALS. THE MAIN TYPES OF THEIR OBLITERATIVE PICTURE PATTERNS HILE the beasts of the open land, such as lions, kangaroos, and many hares, are notable for their almost complete lack of markings, al- though obliteratively shaded and tinted to a high degree, the costumes of many of the forest-haunting and tree-climbing mammals are characterized by strong and beautiful picture-patterns. Among these, there is perhaps none more potent and remarkable than the checkered sun-fleck and leaf-shadow pat- tern, worn by leopards, jaguars, ocelots, giraffes, and other sylvan mammals, and even by some snakes—e. g., several of the great constrictors. It varies, of course, from species to species; but its essential character is always the same, and it is always the handmaid of complete obliterative shading. Who has not noticed, in the forest, the flickering play of circular (or broken) sun-flecks and branched, encompassing leaf shadows? There is no more typical and familiar sylvan sight. Where the forest’s crown is not too dense, this beau- tiful tremulous pattern marks all the brown ground where the matted dead leaves lie, and even checkers the sides and bases of some of the upright trunks, and the tops and sides of the naked lower branches. In deeper woods, where the leafage is extremely full and crowded, little or none of this sun-engendered pattern penetrates to the ground, which then is cloaked in uniform and quiet shade. But somewhere between the dim brown ground and the green and gaudy-flashing tree-tops there is always a large intermediate tract, where, amid trunks and spreading branches, twigs and scattered leaves, the check- ered pattern reigns supreme, dancing softly on the upper side of everything; and, helped by the varied glinting of the lower leaves themselves, it transmutes 132 Fic. 87. CHap. XXI. ag ge of acaptive Jaguar, with a background, as of torest leaves in light and shadow, painted around him. The Jaguar is the same as that published by C. W. Beebe in his “The Bird,” and is here used with the kind permission of Mr. Beebe, E. R. Sanborn and Henry Holt & Co. all that portion of the forest into a shimmering disorder of small, shattered lights and shadows, in which the actual solid details seem inextricably merged. To witness this effect in full, one must of course look at the scene from a point somewhat above it; but the pattern one sees in looking upward through the forest leaves, where they are not so crowded as quite to hide the sky, is of much the same nature. Indeed, this latter sort is in some respects more like that worn by leopards, etc., than is the true sun-fleck pattern. For the predominant effect of the leopard’s pattern, and of that made by leaves against the sky, is of symmetrical dark marks on an irregular light ground—propor- tions which the sun-fleck pattern inverts, except where it is exceedingly pro- fuse. But what we see on the hides of these checkered sylvan beasts is really an apt and efficient generalization of this entire class of forest-patterns, includ- ing the much-used picturing of holes, done all in brown and black and golden forest-interior color. Among the species named at the beginning of this chapter, all but the giraffe are arboreal—that is, tree-climbing—while the giraffe’s great height keeps him also in the region of frequent sun-flecks, as he feeds among low trees and lofty bushes. But the ‘checkered’ pattern in general is so charac- teristic of all lights and shadows in the woods, that, whether the beast so marked have for a background the variegated middles of trees, an under view of their leafy tops against the sky, or the flat brown forest floor, he will almost al- ways be adequately ‘obliterated.’ Everywhere, under leajy trees, exist these simple, elemental patterns, whose likeness on the hides of beasts men deem so beautiful. A leopard or a jaguar stretched out on a lofty branch, lying in wait for monkeys, his deceitfully counter-shaded and spotted coat dappled into still further indistinctness by the very shadows and sun-spots it counterfeits, must be about the most insidiously inconspicuous of hunters. (See Fig. 87.) But not all leopards and jaguars have this brilliantly obliterative forest-color- ation. Both species are rather prone to melanism, being sometimes almost wholly black, with scant traces either of counter shading or pattern. It would 133 be very interesting to discover whether or not the dusky individuals tend to be more strictly nocturnal in their habits; for they are certainly less well equipped for stalking and ambushing their prey in the broad daylight. The giraffe’s or camelopard’s pattern is simpler than the leopard’s, con- sisting of but two well-marked cclor tones instead of three. The dark spots are rich brown instead of black, representing, as it were, a consolidation of the leopard’s two darker tones. Giraffes, however, are subject to a good deal of individual (?), sexual, and geographical variation in the color and shade of the spots, as well as of the branching, irregular light bands by which the spots are divided. But their pattern always maintains its potency for obliteration, particularly in (low) woods, amid shimmering sunshine and leaf shadows, and more distant leaves and leaf-clusters and small branches silhouetting against the sky. In this, their foremost and special obliterative function, the mammalian and reptilian checker-patterns, codperant with a full obliterative shading, must be reckoned among patterns which picture the background, like those much more elaborate and minute of many birds. (See Chapters IV, V, VI, VII, etc.) But they have also, in common with almost all other patterns, and notably all that are sharp and bold, a simple, inherent obliterative effect. The sharp spots thickly scattered over the leop- ard’s coat, and the eccentric patchwork-marks worn by his huge, stilt-legged, ruminant namesake, are in themselves a kind of mask or veil for the solid animal forms beneath them. ‘Their bright, irregular and inorganic pattern takes from the visibility of their wearers’ contours, and goes far toward effac- ing all the minor details and chance-shown lesser lights and shadows of the beasts’ solid but obliteratively shaded forms. A glance at Figs. 1, 14, and 87 will tell the reader more about this than many words. In the case of such an animal as the Jaguar shown in Fig. 87, the perfection of the obliterative shading, denying as it does the presence of a solid body underneath the spots, tends to make these seem to belong to the background, even if that is not elsewhere spotted; and thus the simple ‘retrocessive’ obliteration is in part maintained. Nevertheless, a highly spotted (or otherwise closely marked) 134 “siaysyiqnd sty puv sSayyiyog AtoY Jo worssymnsed oy} qs p dor erp] “sBUITIMS “H “O Aq oanqun mousy ydusrsojoyd WSN qSCLA ‘snondoidsuo0out Ayleurprovayxe oq ysntu £94) YOrA ysureSe pur prime woryeyoSaa fo sodA} [BXOAos oy) JO ou Jo Yyoxed &v ST IWS Oy) YY ‘sovyd SuryUTIp v ye seIqeZ “88 “OTL animal, even though perfectly counter shaded, is of course out of place and more or less clearly visible against a perfectly plain background, because his figure silhouettes against the monochrome scene by virtue of its continuous pattern. This fact, or the converse of it, the noticeableness of a monochrome object against a patterned background, has already been demonstrated (Chap- ter III, Figs. 15-16). But few natural backgrounds, even in the open lands, are entirely immaculate; and hence some degree of flecking is nearly always advantageous, though often not essential, in an animal’s obliterative colora- tion. There is a complete gradation of types between the leopards, ocelots, giraffes and boas, with their rich, specialized, forest-picturing ‘checker’ patterns, through such more weakly and ambiguously spotted beasts as the Ounce and Serval—the one apparently modified for snow and the other for the more open country—to the immaculate lions and (certain) antelopes. In the same way another beautiful and important type of obliterative pattern, namely, transverse striping, grades from its extreme development on the zebras and tigers, through various lessened and modified forms, to its last and slightest appearance on such animals as Livingstone’s Eland, and other antelopes, from which it is but -a step to the stripeless ruminants and car- nivores of the open ground. Among all the bolder obliterative patterns worn by mammals, that of the zebras (Equus zebra and E. burchelli) probably bears away the palm for potency and beauty.* The wonderful photographs of live wild zebras (Figs. 88 and 89), here reproduced with the permission of their author, Herr Schillings, and his publishers, clearly illustrate one main phase of the obliterative force of these beasts’ patterns. The brilliant cross- bands ‘cut their wearers all to pieces,’ and look exactly like the stripings of the lighted reeds across their. shadowed background. To aid in a fuller * Kipling, in one of his “‘ Just So Stories,” ‘‘How the Leopard Got His Spots,” which we have just read for the first time, gives a most keen and appreciative description of the marvelous conceal- ing-power of the costumes of the zebra, leopard, and giraffe. He does not analyze the magic of these patterns, for he says nothing of the principle which underprops it, counter shading; but the magic in operation he has perceived and told about as no other man we know of has. 135 analysis of this effect, and kindred ones, we give also some diagrams—some imitation zebra pictures. Figs. 90, 91, and g2 are photographs of a zebra- shaped model cut out of flat cardboard, and placed amid straws and imita- tion reeds or grasses, artificially arranged. In Fig. go the grasses relieve light against a dark background (as in the real zebra photographs by Schill- ings), and the zebra-to-be—now a wild ass (!)—is tinted uniformly with a shade intermediate between background and grasses. Being actually flat, as the real live zebra is made to appear by its full obliterative shading, this mono- chrome model is not revealed by any look of solidity; yet it is visible and rec- ognizable, because its stripeless surface, with its organic and peculiar outline, interrupts and relieves against the striped pattern behind it. In Fig. g1, the same model, against the same background, has been converted into a zebra, by the application of the proper bands or stripes,—and notice the result! The cardboard figure, standing almost where it stood before, and in exactly the same lighting, has practically disappeared from view. Its sharp bands carry the striate pattern of straws and dusky background across its every part, thereby obliterating it almost completely. (Schillings’s zebras didn’t hap- pen to have a fully and evenly striped background at the moment when he photographed them,* and therefore the effect of actual background-matching is only fragmentarily shown by his pictures.) Fig. 92 shows the same thing over again, with the difference that the striped background is made by imi- tation reeds relieving dark against white paper; the reverse of the former case. These two sorts of background are almost equally well suited to the zebra- pattern, as our pictures show. Both are imitated from nature, the one cor- responding to a landscape with brightly lighted grasses, reeds, or other tall and slender plants, relieving against dark ground or water, or against the shadowed interior mass of their own kind (see Schillings’s pictures, Figs. 88 and 8g), and the other to a landscape in which such plants in somewhat open array relieve darkly against bright sky or water. Again, the shadows of these tall and linear plants—or even of plants more treelike and branching—cast * (not to speak of the extreme abnormality of the lighting).—A. H. T. 136 Artificial ass and zebra, looked at from the low view-point of an ambushed lion, showing the effacing-effect of the stripes in actual operation. (Study this picture from a distance.) Substituted for the Schilling’s photograph, Fig. 89, since the book was printed. upon the sandy or otherwise pale-colored ground in sun- or moon-light, make a pattern very much like the zebra’s.* So also with the reflections of such plants on quiet water. Scenes like these are doubtless typical of all the coun- try in which zebras live. For however arid and barren, through much of the year, are the hills and plains and plateaux over which the Mountain Zebra ranges, or used to range, they are yet clothed with tall plants of many sorts, including rank grasses, which no doubt stand erect for months after they are withered by drought. Furthermore, all beasts must have water, and so the zebras of the dry plains must needs make frequent visits to the nearest living sloughs and rivers. There, by the water’s edge, tall reeds and grasses almost always flourish—often in broad beds of marshy verdure—and there, where all beasts meet to drink, is the great place of danger for the ruminants, and all on whom the lion preys. In the open land, they can often detect their enemy afar off, and depend on their fleetness for escape; but when they are down in the river bed, among the reeds, he may approach unseen and leap among them without any warning. It is probably at these drinking-places that the zebra’s pattern is most beneficently potent. From far or near, the watching eye of the hunter ¢ (bestial or human) is likely to see nothing, or nothing but reed-stripes, where it might otherwise detect the contour of a zebra. The extraordinary brilliancy of these stripes, which for the most part are clear black and white in sharpest contrast (much dimmed, of course, by shadows, when the beast stands amidst vegetation), makes them effectively obliterative at a great distance, where weaker markings would merge and vanish, thereby allowing their wearer’s contour to become apparent. Nor is this brilliance detrimental to the effect in a near view,—the stripes, as Schill- * One may satisfy oneself of this even in the snowy winter woods of northern Europe or America, where, in the slanting light of sun or moon, the shadows of naked trees lie thickly scattered on the pure-white ground. Those of the trunks are mostly parallel, and perspective gathers them into nar- rowly banded patterns, while those of the branches, though much more irregular, also tend to form patterns of this type. t However largely lions and other rapacious mammals hunt by scent, it is not scent, but sight alone, that can serve them when they are down wind of their quarry; and sight alone must guide their ultimate killing dash and spring —A. H. T. 137 ings’s pictures testify, still play their true obliterative part, ‘cutting the beast to pieces’ and wedding him to the strong and manifold striations of the veg- etation all about him. Indeed, a pattern so multiplexly and fundamentally ‘secant’ ‘cuts its wearer’s aspect to pieces’ in almost every view, only fail- ing to be purely obliterative when the beast is seen against a perjectly plain background. Against any appropriate background, on the other hand—as one of reeds and grasses, or even bare-limbed bushes and low trees, or sand streaked with the shadows of any of these plants, or quiet water striped with their reflections—its obliterative effect must be almost perfect. A slightly different phase of this pattern’s use is that which comes into play when the zebra stands amid lower reeds (or other plants) with its upper parts relieving against the sky, or against dim, distant ground, or water. Its body then looks like the upward continuation of the grasses or reeds encompassing its legs;— the dark stripes continuing the reeds upward, and the light stripes between them continuing the sky or other pale background downward, so that the beast’s contour, which otherwise could scarcely fail to show in this position, is still ‘cut up’ and concealed. This ‘letting in,’ or ‘drawing down,’ of sky into an animal’s silhouette is a regular and frequent factor of obliterative coloration, occurring in many forms, in many classes of animals, but most notably among birds and mammals. The reader will hear more of it in the next chapter. Burchell’s Zebra, the species photographed by Schillings,* is much like the now almost extinct Mountain Zebra in general coloration and pattern, but its light markings are more yellowish, and the secant bands are fewer and broader and somewhat ‘differently distributed. On the whole, the Mountain Zebra has the more highly wrought obliterative costume, and that of Bur- chell’s is one step down toward the much slighter pattern of the Quagga (Equus quagga). ‘This beast, which has lately been exterminated, was banded only on the fore part of the body, and there irregularly, with light and dark brown. The transverse leg- and flank-bars of both zebras (but particularly * Strictly speaking, his beasts belong to subspecifically differentiated races of burchelli. 138 Fie. 90. Cardboard ‘zebra’ without stripes, against light straws as in Fig. 91. Photograph, retouched. Fie. 91. Cardboard zebra among straws ‘relieving’ light, like reeds or grasses against dark ground. Photograph, retouched. Fie. 93. Chipmunk (Zamias striatus) among dead leaves, its stripes picturing sticks or leaf-edges and shadows. (These picture-patterns are, of course, based on perfect obliterative shading.) Photographed from life, outdoors. (Captive chipmunk.) Fie. 92. Cardboard zebra among imitation reeds ‘relieving’ dark, as against the sky. Z Photograph, retouched. of the mountain kind), opposed to the more or less vertical body-bands, call for a word of comment. They are an example of ‘secantly’ obliterative mark- ing as distinguished from pure and simple picture-pattern. Striped up and down, the legs would continue the body’s depiction of standing reeds or tufts of grass, but they might also look like an animal’s legs, for their true form and general trend would be obscured but little. The legs, like the body, must be cut crosswise by secant stripes, if they are to be fitly disguised. As was ex- plained in Chapter XIII, such stripes achieve their full effect only when aided by corresponding background-markings. Though the zebra walks amid upright grasses, etc., crisscrossing and horizontal stems and blades are of course common enough in his haunts to yield the required amount of co- operation to his essentially ‘secant’ horizontal leg-bands. When the zebra is lying down, with legs outstretched, these transverse leg-bands have of course a vertical direction, like the body-markings. ‘This, perhaps, is the position which best favors, in the aggregate, the proper working of his ob- literative pattern. Still another detail of these wonderful harlequins’ cos- tumes which demands especial notice is the delicately striped head-pattern. This is worn in almost equally high development by both zebras. It is by every test a picture-pattern. For, just as in the case of the picture-patterned birds (Chapter III, p. 32), this head-pattern of the zebra’s is much smaller and finer than that of the body, as if to match a striped background decidedly reduced by distance—just such a one as the head, being the highest part, must normally have in relation to the lower body. Considering birds alone, a skeptic might suggest that the smallness of the head-pattern may be merely the simple physical consequence of the smallness of the head-jeathers; but such a theory would break down when confronted with the fact that there is a like proportion in the sizes of pattern between the heads and bodies of obliteratively colored hairy mammals. A single feather often contributes the whole of an important spot, or even several spots, to the general pattern, so that small feathers might mean small markings; but patterns made with hair are very different. It takes many hundred crowded hairs to make a 139 small detail of such a pattern as the zebra’s, each separate hair contributing but a tiny share to the effect, so that the markings might be disposed quite arbitrarily on the beast’s coat, as far as the mere form and character of their component parts is concerned. Near akin to the zebra-pattern is that worn by tigers. But the tiger’s black stripes are narrower, further apart, and more broken and irregular, while its ground-color is tawny or deep golden brown instead of white or pale buff. The main obliterative principles, however, are alike in both. The tiger’s coat is obliteratively shaded to minute perfection—darkest along the ridge of the back, lightest on the throat and belly, with intermediate shades for intermediate regions and smaller details of rotundity. His general color is that of the interiors of bushy thickets, reed-beds, the underwood of the loftier jungle, and all brown, half-shaded coverts; while his stripes picture vertical stems and slender trunks in shadow, and also the sun- or moon-en- gendered shadows that such plants cast upon the ground in opener places. As with the zebra, however, his pattern is essentially and intrinsically ‘se- cant’ and obliterative, and nothing short of a perfectly plain background can neutralize its power. He is a beast who hunts his prey by stalking, often in full daylight; accordingly, his huge form has been ‘blotted out’ by counter shading; he is likewise a beast who hunts in and among bushy and grassy thickets, full of upright ‘stripes’ of vegetation, and accordingly he bears a system of generalized dusky stripes upon his brown, obliteratively-shaded coat. The terrible inconspicuousness of the tiger in his native jungles has long been a famous fact, and no evidence on that score need here be cited. Suffice it to say that this inconspicuousness is due primarily to the beast’s obliterative shading, and secondarily to his stripes and his tan-color, which have hitherto alone been held responsible, in the opinion of men. Turn a dead tiger or his stuffed skin upside down in a normal outdoor lighting, and, arrange him as you will against fitting backgrounds, he will be not dim and illusive, but conspicuous, because ,of his now inverted obliterative shading. 140 The tiger has a vast geographical range, extending from the humid jungles of Sumatra to the snowy mountains and plateaux of northern China and Siberia; and like most widely distributed beasts and birds, it has developed several regional races, differing mainly in superficial characters. As the Ounce or Snow Leopard differs from the true leopard type in coloration, so, to some degree, does the North Asian mountain tiger differ from the jungle tigers of the South. Its ground-color is paler—sometimes almost ashen-white —and the stripes are scantier and more broken. These differences correspond to those of the beasts’ habitats—the northern tiger living amid rocks and sometimes snow, in regions where tall upright stalks of vegetation are com- paratively uncharacteristic features of the landscape. Thus, in almost all cases, can one trace an apparent raison d’étre of color- and pattern-differ- ences among nearly allied animals. There are a few cases more baffling, but the seeming obscurity of these doubtless depends on our ignorance of many fine points of difference or affinity in the beasts’ life histories. Some animals, for instance, seem to have a superlatively elaborate obliterative equipment, while other closely allied species with nearly similar habits, living in the same regions, are patterned much more simply. This. is the case with the two ‘harlequin’ zebras and their relative the scantily half-striped Quagga. As the Quagga was banded only on its fore quarters, so the Thylacine, or Tas- manian Wolf, is banded only on its hind. Another Australian marsupial, the little ant-eating Myrmecobius fasciatus, is brilliantly zebra-banded from its shoulders to its tail, But among all the beasts that bear more fragmentary vertically-secant patterns, the African antelopes are probably the most note- worthy. Many antelopes of that continent, indeed, are almost or quite un- marked—smooth brown or gray, obliteratively shaded, with the regulation white or very pale-tinted bellies. But others are brightly, if somewhat scant- ily, striped, and sometimes spotted, on the back and sides and legs, with white and black—especially white. The most amply and regularly banded of these is the Koodoo (Strepsiceros kudu), which has many vertical white stripes on a dark-brown ground. This beast, as its markings would suggest, is an inhab- 141 itant of regions with rather ample vegetation—such as reedy river-margins. Indeed, its average environment and its disguising coloration are very much like the zebra’s. In the same class of ‘secantly’ striped antelopian costumes is that of Livingstone’s Eland, mentioned a few pages back. This mag- nificent great antelope has black marks on its fore legs, while its brown back and sides, otherwise immaculate, are marked with five narrow vertical lines of gleaming white, extending from the ridge of the back about two thirds of the way to the middle line of the belly. These stripes, like those so much more numerous and bold worn by the zebras—and even the Koodoo—are secantly obliterative. They bring down, as it were, narrow slips of sky into the beast’s smooth contour, when he stands upon an eminence and silhouettes against the distance—and thus they ‘cut the contour up’ and tend to obliterate it. Again, under other conditions, these stripes carry the aspect of stray gleaming grasses or reed-stems upward across the eland’s earth-colored, obliteratively shaded body. In all such views, and in others where the ‘picturing’ effect is less pronounced, these stripes are definitely obliterative, always tending to ‘cut up’ the aspect of the eland’s form. The Common Eland wholly lacks these markings, as do many other African antelopes; and here we have an- other case of notable costume-differences among animals with nearly or seem- ingly quite the same habits and environments. No doubt, however, there are really equivalent differences in the beasts’ average surroundings, and in their behavior, even though these have not yet been noticed by man. Thus Livingstone’s Eland may have a greater propensity to stand still in time of danger, or may spend more time amidst tall grasses and reeds, than those of its near relatives that lack the secant stripes. In the same way the more pro- fuse and variegated white markings of the Harnessed Antelopes, containing an admixture of white spots, are probably an indication that these beasts spend an unusually large proportion of their time in and about wet swamps and river borders, where flecks of water-shine—glints and stripes of sky-reflection —are common features of the scene. The small, irregularly circular white spots on the common Harnessed Antelope are indeed almost exactly like those 142 which are prominent in the patterns of certain semi-aquatic mammals; and they also correspond closely to the water-shine flecks of aquatic and swamp- haunting birds. (See Chapter XI, p. 61.) Two beasts of this type are the African Water Chevrotain (Hyomoschus aquaticus) and the South American Lape or Paca (Celogenys paca). Though belonging to different orders (the Chevrotain being a ruminant and the Lape a rodent) these two animals are much alike in general habits, while in pattern they are almost identical. The ground color of the Chevrotain’s coat is richer and redder brown than that of the Paca’s, but it bears almost exactly the same system of white flecks —irregular white spots, in places almost or quite confluent, and forming longitudinal chains or stripes. If these two beasts lived in the same swamps, naturalists would very likely consider their superficial likeness a case of ‘mim- icry.’ But since they live on different continents, there is no disputing the statement that they are independently equipped with water-shine patterns of the same simple, generalized type, which occurs the world over both on mam- mals and on birds. As the zebras’ bands are vertically ‘secant,’ so lengthwise stripes, of which we see the first signs on the Harnessed Antelopes and the two water-beasts just described, are longitudinally secant, like those of certain gallinaceous birds and sparrows, etc. (Chapter XIII, p. 78). On mammals, this truly striped pattern appears in many forms and many degrees of elaboration, be- ing sometimes merely secant, with no very particular suggestion of back- ground-picturing, and sometimes highly ‘pictorial. Many of the North American Ground Squirrels, and Spermophiles (Tamias and Spermophilus), are marked with bright, longitudinally striate patterns of black and brown alone. The Common Chipmunk (Tamias striatus), of eastern North Amer- ica, has few but highly developed markings, its one composite side-stripe being formed by a central whitish stripe inclosed within two black ones. (See Fig. 93.) Painted thus boldly on the little beast’s obliteratively shaded, beautifully dim and flat-looking, honey-brown body, these markings much enhance its elusiveness by distracting the beholder’s eye from any faint mod- 143 ulations of the creature’s form which might otherwise be apparent; while each of these stripes looks in itself like a bright stick, twig, grass-blade, leaf-edge, or weed stem standing out above a shadow—either its own or a more general background-shadow, which shows on either side of it. Or again, this mark- ing suggests a shiny, cylindrical stick or stem, with its central streak of high- light, and the bordering shadows on itself, caused by its own curvature. Still another detail of ground-scene which these chipmunk-stripes suggest is the pattern made by sunlight falling between parallel twigs or stems—narrow, shadow-bordered sun-streaks on the earth or leaves or stones. They are, in short, generalized but most efficient picture-patterns. The western Four- striped Ground Squirrel (Tamias quadrivittatus) is colored and marked much like the eastern Chipmunk, but its stripes, besides being more in number, are narrower, and, as picture-patterns, perhaps even more generalized. Notable among the several other modifications of this pattern to be found on North American mammals is that worn by the beautiful Thirteen-lined Ground Squirrel (Spermophilus tridecimlineatus). The black intervals between its many light-colored secant stripes are traversed by lengthwise chains of bright spots, like slender flower-spikes or little leaves over shadow. On some sper- mophiles (as S. grammurus douglassit), the secant pattern is reduced to a single broad black stripe along the middle of the back—an exaggeration of the dusky ‘ridgepole’ mentioned at the beginning of Chapter XX. An illustration of the obscurer type of generalized flecky background pat- tern on mammals was given in Plate VII. It is a type extremely prevalent among terrestrial mammals. Indeed, if we include all its offshoots, such as the system of regular, scale-like bright flecks on a dark ground, worn for in- stance by certain spermophiles, it is the commonest as it is the obscurest kind of mammalian pattern. It is worn by many terrestrial rodents, etc., of the open ground—e. g., hares, gophers, lemmings, spermophiles—and, variously modified, by many terrestrial forest mammals. Simplified to a close, bark-like grizzling, it is characteristic of many arboreal beasts, such as squirrels and some of the marmosets and lemurs. With very few exceptions, 144 patterns of this kind are accompanied by—or better, they are the accompani- ment of—complete and perfectly efficient obliterative shading. They grade, however, into the more bold and special types of pattern. Thus the ob- scurely flecky pattern of some lynxes shows here and there a spot which is halfway to the clean, sharp “rosettes” of leopards and jaguars. On the other hand, the flecky pattern grades downward into nothing, so to speak, and many mammals are almost or quite without markings, though perfectly coun- ter shaded, and colored brown or gray like the ground or tree trunks. Such are many rats, mice, shrews, etc., and, among large mammals, lions, pumas, wild asses, and many horned ruminants. An interesting parallel between the disguising-equipments of mammals and those of birds is furnished by the obliteratively marked young of many species in which the adults are without markings. The special obliterative costumes of young gulls and other birds was described in Chapter XIV. Among mammals, some of the deer and wild swine are notable examples. The adults are obliteratively shaded but unspotted, while the fawns and little wild pigs are super-equipped with an obliterative pattern of light spots, which lasts through their baby-time of comparative sluggishness and helplessness. These spots belong to the class of generalized flecky background-patterns, inclining on some fawns to sun-fleck and leaf-shadow picturing, and on pigs to water-shine picturing. Some deer—for instance the European Fallow and the Indian Axis Deer—retain the youthful pattern of obliterative flecks through life. This simple, spotty pattern is connected by various intermediates with other types of cervine and antelopine marking—such as the vertical bands of the Koodoo, the bands, stripes and spots of the Harnessed Antelopes, the - softly ‘ruptive’ and background-picturing broad patches of whitish on light brown worn by the American Prongbuck (Antilocapra americana), etc. In- deed, with mammals as with birds, the special types of marking are all more or less smoothly connected one with another by intermediate types—worn, for the most part, by beasts which are evidently intermediate in habits also. But we have now mentioned and briefly analyzed the workings of the main 145 central types of mammalian picture-pattern codperant with counter shading, as far as they are known to us. Wittingly and unwittingly, we have passed by a multitude of minor variations and adaptations, and may even have missed some types of foremost importance. The next chapter deals mainly with the patterns of mammals which lack diurnal obliterative shading.. 146 Fic, 94. Mbega Monkey —a ‘ruptively’ and ‘secantly’ colored forest mammal. His light brush and long side-fringe carry outward into his surroundings his sky-vista-like patch of light, which ‘cuts his form to pieces.’ Photographed from nature by C. G. Schillings. (Cf. Figs. 88-89.] PLATE VIN AHOEN & CO BALTIMORE. EXPLANATION OF PLATE VIII SUNRISE OR SUNSET. -\ By Abbott H. Thayel. , Presenting the very colors of the Spoonbills.. ! [See Plates IX and X.] ROSEATE SPOONBILLS. In morning or evening sunlight. . By Abbott H. Thayer. (See Plates IX and X.] CHAPTER XXII MAMMALS, CONCLUDED, ETC. PATTERNS OF MAMMALS THAT LACK DIURNAL OBLITERATIVE SHADING. SKY-MATCHING PATTERNS OF MAMMALS, AND A COMPARISON BETWEEN THEM AND THOSE OF BIRDS. FIXED ‘DAZZLING’ MARKS, AND OTHER SPECIAL PHASES OF PATTERN-USE N strange contrast to the many beasts whose strongly, moderately, or faintly patterned ground-matching costumes are based on full and perfect obliterative shading, are the few whose bold, clear patterns seem to defy that foremost obliterative law.* Such are the skunks (Mephitis, Conepatus, and Spilogale) in America, the African Zoril or Cape Polecat (Zorilla striata), the Madagascan Golidictis striata and G. vittata, and that queer, badger- like stinker of the Javan mountains, the Teledu (M: ‘ydaus meliceps). These, and many other small or medium-sized carnivorous mammals, are boldly pied with white and black—or dusky brown—and their white is all on the back and sides, while their under parts are uniformly dark.t We have here, as far as these patterns go, a complete inversion of the regular obliterative coloration. A true analysis of this case, which looks at first so mystifying, shows it to be in truth merely one more phase and token of the infallibly close correlation between animals’ costumes and their environment and habits. Two diametrically different uses of white are equally consistent factors of animals’ obliterative coloration. White on the underside, the usual culmina- tion of the almost universal obliterative counter shading, serves as a neutralizer of shadow, an adjuster and maintainer of the even balance between light and dark; white on the upper side, as worn in various forms and proportions by a good many animals, serves to imitate, to picture, the shining sky from which the underside is shaded. On the one hand, it is an all-important ingredient in an ¥ See footnote, p. 123. } The “white” of these animals is in reality pale yellow, brown, or gray.—A. H. T. 147 obliterative compounding; on the other it is used, at its face value, for direct ‘background’ picturing. Skunks, teledus, and the rest, long believed by natu- ralists to be colored for warning conspicuousness (proclaimant of their foul defensive equipment), have, in fact, the universal obliterative coloration. Seen from above on open ground, as men commonly see them, they are some- times very showy beasts, with their big, skylit patches of yellowish white, and their darkly shadowed undersides. But how different is the view their ter- restrial victims get of them! To these little animals—insects and small vertebrates of many kinds—they commonly loom up against the sky, towering high and huge as an elephant would above a skunk. Their big, bold patches of white and black are then about as potently obliterative as a beast’s pattern can ever be—as is proved by our photographs (Figs. 95-97). According to the angle at which they are seen, their lustrous white * either nearly or exactly matches the brightness of the sky, while their dark patches are left to look like bushes, boulders, or more distant trees standing up above the horizon. All this is attested beyond question by our photographs, as the reader will agree. And he must consider that these pictures were taken in full daylight—a far severer test of such an effect than the dim light of night. For at night, sky and sky-pictures being correspondingly and greatly dimmed, the casual discrep- ancies of shade between them are reduced to almost nothing. The whole illusion, of course, is better in a dim light, since it depends wholly on bold, simple counterfeiting of background ‘values’ or shades. Skunks, and most or all of the other mammals that are colored like them, are grubbing terrestrial hunters, and nocturnal, and hence are served by their boldly pied white and black patterns in the manner shown by our pictures, but on the whole even more potently, by virtue of the dimness of the light in which they commonly hunt. The white stripe on the Common Skunk’s forehead and snout—a mark- ing shared by several other grubbing ground-beasts, and among them some with light colored bellies, e. g., the badgers (Meles and Taxidea)—plays an im- * The actually pale yellow hairs are so lustrous as to look brighter, in such views, than lusterless pure white could. 148 Ftc. 95, Common Skunk as he appears to mice, grasshoppers, and other small ground- Fic, 97, Mouse’s or Cricket’s view of the Common Skunk, as in Fig. animals—his dark passing for distant trees, or bushes, his white for sky. . 15, ete. Photographed outdoors from a stuffed skin. Photograph, outdoors, from a stuffed skunk-skin. (Slightly retouched.) Fig. 98. Common Skunk, as in Fig. 97, but with sky ‘back- ground’ cut off by dark, making his white conspicuous, indistinguishable against the sky. [Ct. Fig. 95, ete.] ; hot: : td tuffed skunk Pl kin, Fic. 99. Conepatl or Prairie Skunk, scen from his prey’s point of view. [Cf. Fig. 95.] Stuffed skin, outdoors, photograph. Fie. 100. Conepatl or Prairie Skunk, as in Fig. 99, but with sky back- ground cut off. [Cf. Fig. 98.] Stuffed skin, outdoors, photograph. portant part in his disguisement. As he shambles over a field, with his seeking snout held close to the ground, this white stripe, in the view of the little ground beasts he approaches, ‘lets down the sky’ through his black head and fore- shortened bulky body, splitting the apparition into narrow, un-beast-like halves, which look like sticks or weeds or more distant bushes or boulders showing above the horizon. The several variations in the form and proportions of the sky-picturing white top-patterns of skunks and skunk-like beasts are all in more or less obvious conformity with differences in their wearers’ ways and places of life. ‘Thus the Common Skunk’s main white pattern has a somewhat irregular, a waved and insected, lower outline; while that of the Conepatl or Prairie Skunk (Conepatus mapurito, etc.) is square-cut and straight; and these differences are doubtless, nay, obviously, matched by differences in the beasts’ average backgrounds. For the eastern skunk is more often seen against a sky-line broken by trees, stones, and bushes, than is his desert- haunting relative. (Compare Figs. 99 and 100 with Figs. 95 and 98.) Al- though these photographs are from shapeless stuffed skins, they can be trusted in the matter of the main effects of the beasts’ patterns, and even the main pattern-differences between the two species. Evidently, the Conepatl has just so much of his back sharply and levelly cut off by white, as, in the aver- age view of the little ground beasts he hunts, at the moments when it most profits him to be concealed from them, would show above the (unbroken) horizon. The pattern of the common eastern skunk renders the same serv- ice, but with the difference that it represents a sky-line notched by trees, etc., as we have seen. The Teledu of Java is marked much like the Cone- patl, though its white ‘blanket’ is narrower. Other beasts with more or less nearly the same habits, and the same general system of sky-picturing, are the Ratels (Mellivora capensis and M. indica), the Wolverine or Glutton (Gulo luscus) in some pelages, the Great Ant-eater (Myrmecophaga jubata), the Tamandua Ant-eater (Tamandua tetradactyla), and, to some extent, the Tasmanian Devil (Sarcophilus ursinus). But most of these beasts have even browner (or grayer) ‘white’ patterns. Many of them, on the other 149 hand, like several of those previously mentioned (skunks and badgers), have head- and face-masking as well as body-masking sky-picture patterns. Such markings, indeed, are very common among grubbing carnivorous and in- sectivorous mammals. Anyone who will seek through a big museum col- lection of mammals will be able to add many cases of both sorts to the above casual and fragmentary list. The profusely striped top-pattern of the Spilogale and the Zoril, etc., is merely another form of the same costume, and performs nearly the same service. It pictures sky seen through obstruct- ing twigs or narrow leaves, and is, with little doubt, significant of more sylvan or bush-land-haunting habits on the part of its wearers. It looks somewhat, also, like the converse of such a sky-scene—sharply contrasting linear lights and shadows on the ground, in moonshine. But the light markings, being almost white, are over-bright for this ground-picturing service, whereas they exactly fit the other. True, the effect of such brilliant, sky-lit stripes, con- trasted with the shadowed black of the under parts, is powerfully ‘ruptive’ in all views, even against the ground, ‘breaking the beast up’ into un-beast- like stripes and patches. Indeed, against the most brightly moonlit and most sharply shadow-brindled ground, such a beast must be pretty well ob- literated, and even his motion may be masked,—by the motion of the ground- shadows, cast by wind-swayed vegetation. But such conditions are highly occasional, and against open ground the spilogale’s mantle of white stripes must often reveal him, especially when he moves about. It would seem that he might be much better equipped for concealment in almost all such views if he were counter shaded and more softly striped—or mottled, or even wholly unmarked. Think how ghostly-illusive against moonlit ground are the ob- literatively shaded and faintly patterned hares, and kindred beasts! Ap- parently, the dominant use of the spilogale’s pattern is not ground-picturing, but the matching of sky glimpsed through dusky obstructions—a purpose which the obliteratively shaded, dimly patterned animal’s costume could by no means serve. (See Fig. 103.) The spilogale probably has few large enemies to fear, and—just as with skunks, teledus, etc.—it is evidently of most 150 Fic. 101. Spilogale, or Little Striped Skunk, seen from mouse’s and cricket’s position—his dark stripes passing for vegetation, and his white stripes for the sky. [Cf. Figs. 95-99. Stuffed skin, outdoors, photograph, Fic, 102, Spilogale, or Little Striped Skunk, seen from men’s and hawks’ point of view. [Cf Fig. 101.] Stuffed skin, outdoors, photograph. Fic. 103, A Compound Picture. (Photographic, except for the upper rear-view of the Hare. The crouching Hare was photographed from life; the Skunk from a stuffed skin.) ‘This picture, by show- ing the ola familiar type of obliterative coloration alongside of the obliterative effect of white upper- surface patterns, so long supposed to make their wearer couspicuous, prepares the reader to discover that all patterns and colors whatsoever, of all animals that ever prey, or are preyed on, are, under certain normal circumstances, obliterative. Animals which need to escape notice when looked at from above, match the ground. Those that must not be detected when looked at irom a lower level, match the sky, or whatever combination of sky, vegetation, etc., commonly forms their backgroun from this view-point. Between these two axteanoleitwe count sky and sky-reflected-in-water as one— are ranged the color-schemes of most of the animal kingdom. In this illustration the Skunk against the sky loses the white parts of his silhouette, and his dark is left to look like bushes, ete., in the background (4). On the other hand, the Skunk against the ground loses his dark parts, and his white, though often, as here, conspicuous in itself, has a largely inorganic and deceptive contour, and, when seen amid obstructing twigs and leaves, especially at night, is potently obliterative (Cf. Figs. 104-106). It is in fact not pure white, but nearer to the color of bleached dead leaves and twigs. The Leaping Hare’s white rump vanishes against the sky (C), from the sight of the creeping fox, or other quadruped pursuer, The fox’s eyes are, at that moment, lower than the Hare’s tail, and he sees it against the sky, (or, in the woods, the sky’s light through the leaves). (J) shows a man’s view of the same hare, and explains why men have thought this white conspicuous. To a young hare this white rear of the mother would present the same difficulty as to the fox. On the other hand, a crouching Hare, so admirably merged into his surroundings when looked at from above, (), is boldly conspicuous when seen from the position of a mouse or cricket, as in (#7), and in the detached figure of a Tame Hare, (G@). Ifa mouse could theorize, he would know the skunk to be obliteratively colored, but would consider the hare, execpt when it was running away from him, a most conspicuous animal, thus reversing men’s notions. In this illustration, the hare in_ profi : St I D le against the sky would be still more convincing were his members extended for action, showing a more revealing outline. [Cf. the Domestic Hare (@).] importance to him to be masked for the eyes of the little ground beasts on whom he feeds. (See Figs. 101-102.) Seen against snowy ground, which is common enough through a large part of the eastern skunk’s range, a boldly pied pattern of white and black, such as he wears, is of course most potently ‘ruptive.’ But it does not truly oblit- erate, because all the black part of the beast is left rankly conspicuous, and has too peculiar a form, in such a view, to be easily ignored, or mistaken for a land- scape-detail. Northern skunks, however, vary a good deal in pattern, and the very whitest of them are doubtless well disguised, in certain views, against showy ground, ‘particularly amid trees and sticks and stones and bushes and other inanimate dusky details. In this case, as throughout the whole great field of phenomena we are studying, it stands to reason that a special development of costume must serve minor as well as major ends.* But how- ever potently ‘ruptive’ (and therefore essentially obliterative) in their effect when seen against the ground the whitish patterns of skunks and skunk- like beasts may sometimes be, the paramount function of these patterns is certainly the picturing of sky, as our figures show (Figs. 95-103). Both uses are served, perhaps almost in equal measure, but with the balance of importance probably tipped somewhat toward the ground-matching function, by the wholly or almost wholly white costumes of several snow-land animals. Such—to begin with those least remote from the skunks—is the rare, bear- like Ailuropus melanoleucus, of Thibet; such are the Arctic hares and foxes, the boreal weasels and some of the boreal hares, and the Polar Bear. Almost all of these, and their counterparts among boreal and Arctic birds—the ptar- migans, the snow buntings, the Snowy Owl, and the White Gerfalcon—almost all of them, mammals and birds alike, have a few sharp black markings in their mainly immaculate white costumes. These evidently serve as what may be called ‘distractive’ or ‘fixed dazzling’ marks. They are, in most cases, too small to show except in a very near view—when, by their sharp but isolated * Or, in terms of the Natural Selection theory, that each development is the product of the sum of all its uses, big and small. e I51 and noncommital conspicuousness, they tend to draw and hold the eye’s attention,—in a sense, to dazzle it, so that it less readily discerns the faintly shown snow-white body of their wearer. The working of this principle is illustrated by Figs. 104-106. Most ptarmigans have black tails, which, folded and largely hidden by white ‘coverts’ when the bird is skulking, show as nar- row, sharp black marks, drawing the eye to a point away from the bird’s rotund body, ‘dazzling’ it slightly, and presenting it with a view of what might be a little twig or stone or other dusky landscape-detail. Some ptar- migans in white winter plumage have also a black face-mark, which serves the same purpose, and also masks the bird’s round and lustrous eye, in the manner explained in Chapter XIV. The Snowy Owl and the White Ger- falcon are more profusely flecked with ‘distractive’ black marks. Notwith- standing the special inherent ‘dazzling’ function of such markings, they all belong essentially to the ‘picture’-pattern class. For, if they did not also look like dark landscape-details, they would in the long run tend to reveal rather than conceal their wearers. ‘The northern weasels in their white winter dress have ‘distractively’ jet-black-tipped tails. Polar Bears and Arctic Foxes have no such markings, unless we count their black snouts and dark eyes. Very likely such beasts when they are skulking partly close their eyes, masking their too characteristic circular or oval form. The little Thibetan Snow Bear (Ailuropus), on the other hand, has more than a mere ‘distrac- tive’ display of black in its white costume. Its legs, its ears, and a narrow shoulder-mantle are solidly black, and it has black spots around its eyes. Thus it is well fitted for obliteration. or great inconspicuousness against either snowy ground or sky, in a country full of dark boulders or bushes, or both.* In much the same manner, and presumably for life amidst back- grounds of the same general aspect, is the Kamchatkan white-shouldered Sea Eagle disguised. But in his costume the dark preponderates over the white. One more principal phase and function of mammalian sky-matching costume remains to be described. That is the ‘obliteration’ of fleeing deer, * The white breast-marks of several of the black bears belong in this same class of obliterative patterns. 152 Fie. 104. Fie, 105. ~ i illustrate the obliterative effect on faintly-showing contours of sharp and strong internal marks. The altri one, 2 ay pone cep i that the Butterflies’ or Letters’ contours near the bold marks vanish, while those apart from aaaekiugs remain perfectly distinct. The markings, at the same time, ally themselves to kindred details in the background, Fie. 106. Fie. 106. Here the spectator will discover, if he recedes far enough, (seven or eight yards in a bright light) that all three of the monochrome butterflies, even the dimmest, can be seen further, or in a less illumination, than the normally and brightly patterned one. This latter fades first. This shows how contrasted juxtaposed color-notes efface each other, so that contrary to the old theories they are not so good as monochrome for revealing the weare: M r, even in the open, while, seen through the average tracery of out door vegetation, they almost guarantee disguise and concealment. See Plate V. antelopes, hares, etc., by white tails and rumps. More characteristic even than the grubbing carnivores’ sky-matching head-patterns are these more or less ‘eclipsable’ rear-end flight-masks of timid, fleet ruminants and larger rodents. When these beasts flee at night before terrestrial enemies—which are nearly always of lower stature than their quarries, and in most cases addition- ally fated-to look upward at them by the fact of the quarry’s high-jumping gait, and their own crouching and slinking—when these hunted beasts flee thus, their brightly displayed sky-lit white sterns blot out their foreshortened bodies against the sky. In the night, the illusion must often be complete, and most beneficent to the hunted beast, who by its aid may often just avoid the lion’s or the tiger’s or the cougar’s or the cheetah’s killing second spring ;— vanishing into air, as it were, before the predator can get his aim for the leap, or before he can perceive the direction of his quarry’s flight. For photographic illustrations of this marking’s obliterative effect, see Figs. 107-115. Such rear-end sky-pictures are worn by most fleet ruminants of the open land, and by many rodents with more or less nearly corresponding habits—notably the hares, and several smaller running or leaping rodents whose terrestrial enemies are many of them beasts of low stature—like weasels, minks, snakes, etc., and foxes, that slink and crouch. The ruminants that lack such mark- ings are most of them either extremely big and powerful—like some of the huge African antelopes, and almost all the bovine beasts—or else they live in dense tropical forests, where at night there is very little ‘overhead’ light for them to relieve against. Some of the little South American jungle deer are good examples of this forest-haunting class. All these various sorts of wonderfully effective sky-picture patterns are worn by animals that are habitually or most commonly looked up at, either by their enemies or by their quarries. Indeed, the presence or absence, the high or scanty development, of such markings in an animal’s pattern, seems to be a direct and accurate indication of whether, in the average view of the creatures from whom it most profits the animal to be concealed, it comes above or below the horizon line—and of the largeness of the preponderance in either 153 direction. Thus gulls, terns, and many other sea birds, which fly between blank ocean and blank sky, getting their food from the water, are largely cloaked in sky-matching white. So, among land birds, are the often-men- tioned Snowy Owl and White Gerfalcon, which fly and hunt over treeless barrens and the bare ocean-shore. So are most swans, some geese, some pel- icans, and several herons, storks, ibises, cranes, etc..—birds that swim or wade, seeking their food below them in the water, and doubtless subject, in all or most cases, to persecutions from aquatic enemies. Showy as these birds are against the muddy ground and dark-green vegetation, they are equipped for the utmost possible inconspicuousness when seen from below, against the sky. Viewed at the proper angle, they must, like the skunk’s back, be almost invisible, especially at night. (An opaque body directly in- ter posed between the beholder and the zenith cannot fail to show dark, however colored; but the upper surfaces of a snow-white opaque body looked at in an obliquely upward direction, so that it is seen sky-lit and at the same time against the sky, may exactly match the brightness of its luminous background —all of which is shown by Figs. 107-115.) Plates VIII, IX, and X, with their Flamingoes and Roseate Spoonbills, reveal the simple fact, which seems never to have been noticed, that these traditionally “showy” birds are, at their most critical moments, perfectly ‘obliterated’ by their colora- tion. Conspicuous, in most cases, when looked at from above, as man is apt to see them, they are wonderfully fitted for ‘vanishment’ against the flushed, rich-colored skies of early morning and evening; and such are their normal backgrounds, at their chief feeding-times, in relation to their aquatic enemies (sharks, alligators, tortoises, anacondas, etc.) and those of their prey that see at all. Of course, against the dawn or the sunset itself, these birds must show dark, just as with white against the zenith; but the rosy hues very com- monly suffuse both sides of the sky, so that, in either twilight, the Spoonbill’s, Ibis’s or Flamingo’s adluminated ruddy color very often has a true ‘back- ground’ of illuminated ruddy sky. Further, the side of such a bird actually sunlit, at early morning or late afternoon, is made to glow so brilliantly as to 154 Fie. 107. Prong-Buck as commonly Fic. 108. Prong-Buck’s obliterative Fie. 109. The same as Fig. 107, but with the seen by all animals whose eyes are on a rump-mark seen against the ground, as Prong-Buck’s legs and the landscape shaded lower level than its rump. (This, of course, men see it, their eyes being on a higher more nearly into one flat ‘tone,’ such as the includes the Prong-Buck’s terrestrial ene- level. beholder would really see in the night. Body mies, such as wolves and cougars—not to Photographed from a stuffed skin. and legs, not coming against sky, would, at speak of the beast’sown young, which have Soiled rump-mark covered with white rabbit skin. night, be invisible, or very nearly so. been supposed to use their parent’s snow- ature, in such cases as the Hare’s and Prong- white stern as a ‘banner’ to follow in Buck’s, evidently ‘obliterates’ with white exactly flight.) 5 as much of the animal as his carnivorous enemies, n all these photographs from a stuffed when close upon him, would see against the sky, beast, the rest of the animal is much more to guide their final leap. conspicuous against the ground than it Retouched photograph of stuffed skin. would be in nature. Photographed trom a stuffed skin, Soiled rump-mark covered with white rabbit skin Fie, 110, Prong-Buck against the sky, presenting a con- spicuous silhouette of all bué the rump-mark, which would show were it of any darker tone than white. Soiled rump mark covered with white rabbit skin. Photograph of stuffed skin. (Except where the contrary is expressly stated, all our photographs are absolutely unretouched.) Fic, 111. The common aspect of animals showing against night sky, if they have no white top-patterns. Fig. 112. (Dead) Northern Hares seen from the level of a creeping fox. These photographs show that from this view- point the so-called banner-mark, the white, is precisely what does nof show. Vic. 113, Dead Northern Hare, seen from men’s level. Hares in danger from over-head foes, e. g., birds of prey, doubtless resort to crouching ‘invisible’ rather than to run- ning, while, on the other hand, enemies which trail them force them to leap away. Photographed, out-doors. Fig. 114. White card, as in Fig. 115, but invisible against the sky, because the camera was lower than the card, just as a panther or fawn would be lower than the deer’s buttocks. Photograph. Fie. 115. A white card—as it were a detached rump-mask against the ‘ground.’ Photograph, look like a real sunset or dawn, repeated, on the opposite side of the heavens,— either east or west as the case may be. ' All these white and pink (or red) fishing-birds and vegetable-eaters have the habit of staying more or less quiet, for longer or shorter periods, in the near vicinity of their aquatic prey and enemies. Egrets and white herons stand hour-long motionless or wade cautiously about in shallow ponds, rivers, lagoons and estuaries,—ready with poised head and lancelike bill to stab the first fish or frog that comes within their reach. (See Figs. 116-118.) White pelicans fish while swimming; but the brown pelicans plunge headlong from on wing into the water, catching their prey by violent abrupt assault, like the gannets, the terns, the kingfishers, and the Osprey; and all these plunging fishers have characteristics of coloration in common, which are not typical of the stealthy fishers. These consist in brilliant ruptive patterns, chiefly on the head, but sometimes also on the wings and body—patterns which doubtless have the effect of confusing the suddenly assaulted quarry as to the exact position and the true form of its attacker. Such are the tern’s black head- caps, the black or dark marks about the base of the Common Gannet’s pale sea-green bill, the clearly-contrasted brown and white stripes and patches of the brown pelicans’ heads, the motley costumes of kingfishers, etc. At the instant of attack, such markings ‘break up’ and confuse the apparition of the attacker, doubtless often to the bane of the attacked, whose life or death must often depend on the turn of a hair toward quicker or slower, surer or less sure darting off. Stealthy fishers, on the other hand, would in many cases be misfavored by such ‘ruptive’ markings, which during their quiet stalking and watching would increase their conspicuousness against the sky. On the other hand, even the black wing-tips and like markings of gannets and other plunging fishers, serve as ‘dazzling’ and ‘distractive’ marks,—like those of. the tails of winter ptarmigans and weasels—at the moment of the bird’s arrowy arrival with part-folded wings (and tail) among his finny prey. Then there are two or more classes of animals merely patched with sky- pictures. Such are the more or less largely white-backed skunks, and kin- 155 dred mammals, and the many arboreal birds and several arboreal mammals which have biggish white spots or patches on their backs and sides. The ground beasts of this group are, as has been explained, specially equipped for concealment against the horizon-bordering sky; while the tree birds’ and tree beasts’ more or less ample, irregular patches of sky-picturing white are in evidently just proportion to the greater or less amplitude and frequency, in their average backgrounds, of sky vistas, and light foliage vistas amidst dark leaves and twigs and tree trunks. Next and last in order come the terrestrial and semi-terrestrial birds and other animals which are equipped for concealment against the landscape below the horizon, and have little or no hint of sky-picturing in their costumes. Such are many woodland ground birds, notably the brown tropical ones described in Chapter XIX. Such also are most of the terrestrial woodland mammals; such, again, are snipe, goatsuckers, and many of the small, close-lying Gal- line (most arboreal species have fragmentary sky-pictures—see the Cock Ruffed Grouse in Plate II); such are most frogs and toads and many ground lizards; such are sand crabs; and such, in the most marked degree, are many terrestrial snakes—for instance the Copperhead, shown in Plate-XI (Chap- ter XXIII). Most of these creatures are patterned with elaborate ground- pictures, and on some species, like the Copperhead snake, these have reached a very high degree of specialization. Because of their low stature and their ground-haunting, close-lying habits, such animals as these scarcely ever, in the view of predators or quarries, stick up above the horizon line. They are colored, with exquisite efficiency, for obliteration or extreme inconspicuousness when looked down at, against a background of mother earth and her lowly vegetable mantle. If men were Lilliputians, and looked up at the flanks and back of the Copperhead snake, as in reality they look down at the sky-pic- turing back-pattern of the piebald skunk, the snake’s coloration would seem to them just as ‘‘conspicuous” and inappropriate for disguise as the skunk’s has always seemed. ‘‘It’s all in the point of view;”’—and if we would learn the true, the compellingly apparent significance of animals’ costumes, we must 156 EXPLANATION OF PLATE IX ROSEATE SPOONSBILL. ° Before sunrise or after sunset; matching the sky behind it, (i. e., the western sky at dawn, or the eastern sky at sunset). SUNRISE OR SUNSET. A typical sky, much like the aspect of the Flamingoes. en FLAMINGOES. ; mee, 7 ote, rea Ryans a ual Before sunrise or after sunset, oes the ty, ; behind them, as in the Spoonbill picture. ' "tis angio? BBs D By Abbott H. Thayer These various sketches of Flamingoes and Spoonbills show how wonderfully such birds match or reproduce the colors of morning or evening skies to the eyes of the inhabitants of the water in which they: wade—both their enemies, such as anacondas, alligators, sharks, etc., and such of their prey. as can see them. Commonly, the bird’s upper outline ‘melts’ into the sky, leaving the rest of his contour, seen through the Water, agitated and muddied by his feet, to be lost i in the indeterminate color-mass of the flock. Shaken and jumbled ’ by the continual agitations of the water, the image of the flock retains, for eyes beneath the surface, only its color and. its position, both of which coincide with those of the dawn or sunset, (though on the other side of the heavens) or the flushed sky opposite. Through all stages of twilight this living mass, seen against the less lighted parts of the sky, blends into. it, undergoing kindred ehanges of illumination, and when full sunlight bathes it, its lighted side blazes out into a perfect representation of the dawn or sunset itself, though in the opposite quarter. In the case of the Red Flamingo the bird’s legs, including its feathered thighs, are purplish instead of orange-red, in. keeping with the color-gradation of the sky, which is, at these hours, commonly purplest ‘at the lowest point, having its purest reds and oranges a little highér. up. Thus, each part of the bird has every possible opportunity of matching its background, —A. H. T. PLATE 1X AWOEN & GO, BALTIMORE | ‘LH “V— JS] UMBP 10 yastINS oy} THOTT susavay ay; fo waruonB opsoddo oy? we ‘asmoo jo ‘skvmje ysnoyye {