until the movement which began in the far north is com- | prolonged throughout some 50° or 60° of latitude, the This seems satisfactorily to explain the southward movement of all migrating Birds in the northern hemisphere; Homeward but when we consider the return movement which takes ovement. place some six months later, doubt may be entertained whether scarcity of food can be assigned as its sole or sufficient cause, and perhaps it would be safest not to come to any decision on this point. On one side it may be urged that the more equatorial regions which in winter are crowded with emigrants from the north, though well fitted for the resort of so great a population at that season are deficient in certain necessaries for the nursery. Nor does it seem too violent an assumption to suppose that even if such necessaries are not absolutely wanting, yet that the regions in question would not supply sufficient food for both parents and offspring-the latter being at the lowest computation, twice as numerous as the former-unless the numbers of both were diminished by the casualties of travel.1 But on the other hand we must remember what has above been advanced in regard to the pertinacity with which Birds return to their accustomed breeding-places, and the force of this passionate fondness for the old home cannot but be taken into account, even if we do not allow that in it lies the whole stimulus to undertake the perilous voyage. urn of male igrants. "It appears to me probable that here, as in so many other cases, 'survival of the fittest' will be found to have had a powerful influence. Let us suppose that in any species of migratory bird, breeding can as a rule be only safely accomplished in a given area; and further, that during a great part of the rest of the year sufficient food cannot be obtained in that area. It will follow that those birds which do not leave the breeding area at the proper season will suffer, and ultimately become extinct; which will also be the fate of those which do not leave the feeding area at the proper time. Now, if we suppose that the two areas were (for some remote ancestor of the existing species) coincident, but by geological and climatic changes gradually diverged from each other, we can easily understand how the habit of incipient and partial migration at the proper seasons would at last become hereditary, and so fixed as to be what we term an instinct. It will probably be found, that every gradation still exists in various parts of the world, from a complete coincidence to a complete separation of the breeding and the subsistence areas; and when the natural history of a sufficient number of species is thoroughly worked out, we may find every link between species which never leave a restricted area in which they breed and live the whole year round, to those other cases in which the two areas are absolutely separated." A few more particulars respecting Migration are all that can here be given, and it is doubtful whether much can be arlier re- built upon them. It has now been ascertained by repeated observation that in the spring-movement of most species of the northern hemisphere the cock-birds are always in the van of the advancing army, and that they appear some days, or perhaps weeks, before the hens. It is not difficult to imagine that, in the course of a journey 1 If the relative proportion of land to water in the Southern Hemisphere were at all such as it is in the Northern, we should no doubt find the birds of southern continents beginning to press upon the tropical and equatorial regions of the globe at the season when they were thronged with the emigrants from the north, and in such a case it would be only reasonable that the latter should be acted upon by the force of the former, according to the explanation given of the southward movement of northern migrants. But, though we know almost nothing of the migration of birds of the other hemisphere, yet, when we regard the comparative deficiency of land in southern latitudes all round the world, it is obvious that the feathered population of such as now-a-days exists can exert but little influence, and its effects may be practically disregarded. In principle Captain Hutton had already foreshadowed the same theory.-(Trans. New Zeal. Inst. 1872, p. 235.) wing. perceptible distance, and it can hardly be doubted that in weather on For many years past a large number of persons in dif- Presumed ferent countries have occupied and amused themselves by effects of carefully registering the dates on which various migratory migration. Birds first make their appearance, and certain publications 3 abound with the records so compiled. Some of the observers have been men of high scientific repute, others of less note but of not inferior capabilities for this especial object. Still it does not seem that they have been able to determine what connection, if any, exists between the arrival of birds and the state of the weather. This is not very wonderful, for the movements of the migrants, if governed at all by meteorological forces, must be influenced by their action in the places whence the travellers have come, and therefore to establish any direct relation of cause and effect corresponding observations ought equally to be made in such places, which has seldom been done.* 3 These are far too numerous to mention here. Perhaps the most very exhaustive memoir by Herr Palmén,3 but it would be impossible within the limits of the present article to do more than mention his results concisely. He enters very fully into this part of the enquiry and lays down with much apparent probability the chief roads taken by the most migratory Birds of the Palearctic Region in their return autumnal journey, further asserting that in the spaces between these lines of flight such birds do not usually occur. These main routes are, he states, nine in number. The first (A-to use his notation), leaving the Siberian shores of the Polar Sea, Nova Zembla, and the North of Russia, passes down the west coast of Norway to the North Sea and the British Islands. The second (B), proceeding from Spitsbergen and the adjoining islands, follows much the same course, but is prolonged past France, Spain, and Portugal to the west coast of Africa. The third (C) starts from Northern Russia, and, threading the White Sea, and the great Lakes of Onega and Ladoga, skirts the Gulf of Finland and the southern part of the Baltic to Holstein and so to Holland, where it divides-one branch uniting with the second main route (B), while the other, running up the valley of the Rhine and crossing to that of the Rhone, splits up on reaching the Mediterranean, where one path passes down the western coast of Italy and Sicily, a second takes the line by Corsica and Sardinia, and a third follows the south coast of France and eastern coast of Spain all three paths ending in North Africa. -all The fourth (D), fifth (E), and sixth (F) main routes depart from the extreme north of Siberia. The fourth (D) ascending the river Ob, branches out near Tobolsk—one track, diverging to the Volga, descends that river and so passes to the Sea of Azov, the Black Sea, and thence, by the Bosphorus and Ægean, to Egypt; another track makes for the Caspian by way of the Ural River and so leads to the Persian Gulf, while two more are lost sight of on the steppes. The fifth (E) mounts the Jennesei to Lake Baikal and so passes into Mongolia. The sixth (F) ascends the Lena and striking the Upper Amoor reaches the Sea of Japan, where it coalesces with the seventh (G) and eighth (O) which run from the eastern portion of Siberia and Kamchatka. Besides these the ninth (X) starting from Greenland and Iceland passes by the Faroes to the British Islands and so joining the second (B) and third (C) runs down the French coast. These being the main routes it must be added that, in Herr Palmén's opinion and that of many others, nearly all river-courses form minor routes.1 As a rule it would seem as though Birds were not dependent on the weather to any great degree. Occasionally the return of the Swallow or the Nightingale may be somewhat delayed, but most Sea-fowls may be trusted, it is said, as the almanack itself. Were they satellites revolving around this earth, their arrival could hardly be more surely calculated by an astronomer. Foul weather or fair, heat or cold, the Puffins (Fratercula arctica) repair to some of their stations punctually on a given day as if their movements were regulated by clock-work. Whether they have come from far or from near we know not, but other Birds certainly come from a great distance, and yet make their appearance with scarcely less exactness. Nor is the regularity with which certain species disappear much inferior; every observer knows how abundant the Swift (Cypselus apus) is up to the time of its leaving its summer-homein most parts of England, the first days of August-and how rarely it is seen after that time is past. Statistics of It must be allowed, however, that, with one exception, migration. the mass of statistics above spoken of has never been worked up and digested so as to allow proper inferences to be made from them, and therefore it would be premature to say that little would come of it, but the result of that one exception is not very encouraging. Some twenty years ago Dr von Middendorff carefully collated the records of the arrival of migratory Birds throughout the Russian Empire, but the insight into the question afforded by his published labours1 is not very great. His chief object has been to trace what he has termed the isepipteses (loos = æqualis, èñíπτησis = advolatus) or the lines of simultaneous arrival, and in the case of 7 species2 these are laid down on the maps which accompany his treatise. The lines are found by taking the average date of arrival of each species at each place in the Russian dominions where observations have been regularly made, and connecting those places where the dates are the same for each species by lines on the map. The curves thus drawn indicate the inequality of progress made by the species in different longitudes, and assuming that the advance is directly across the isepiptesial lines, or rather the belts defined by each pair of them, the whole course of the migration is thus most accurately made known. In the case of his seven sample species the maps show their progressive advance at intervals of a few days, and the issue of the whole investigation, according to him (op. cit. p. 8) proves that in the middle of Siberia the general direction of the usual migrants is almost due north, in the east of Siberia from south-east to north-west, and in European Russia from south-west to north-east. Thus nearly all the migrants of the Russian Empire tend to converge upon the most northern part of the continent, the Taimyr Peninsula, but it is almost needless to say that few of them reach anything like so far, since the country in those high latitudes is utterly unfit to support the majority. With the exception of some details, which, though possessing a certain special interest, need not here be mentioned, this treatise fails to shew more; for the fact that there are places that notwithstanding their higher latitude are reached by Birds on their spring-migrations sooner than others in a lower latitude was already known. Routes of The routes followed by migratory Birds, so far as our migrants. information at present extends, has been the subject of a rally the case, by heavy falls of snow, such Birds are of course driven southward to seek their living. But as often as not the Birds arrive with the kind of weather they are commonly held to prognosticate, while sometimes this does not follow their appearance. 1 Die Isepiptesen Russlands. Grundlagen zur Erforschung der Zugzeiten und Zugrichtungen der Vögel Russlands. St Petersburg: 1855. Hirundo rustica, Motacilla alba, Alauda arvensis, Oriolus galbula, Cuculus canorus, Ciconia alba, and Grus communis. 3 Om Foglarnes flyttningsvägar (Helsingfors: 1874). In this and the work of Dr von Middendorff, already cited, reference is made to almost every important publication on the subject of Migration, which renders a notice of its very extensive literature needless here, and a pretty full bibliographical list is given in Prof. Giebel's Thesaurus Ornithologia (i. pp. 146-155). Yet mention may be made of Prof. Schlegel's Over het trekken des Vogel's (Harlem: 1828), Mr Hodgson's "On the Migration of the Natatores and Grallatores as observed at Kathmandu" in Asiatic Researches (xviii. pp. 122-128), and M. Marcel de Serres's Des causes des Migrations des Animaux et particulièrement des Oiseaux et des Poissons (Harlem: 1842). This last though one of the largest publications on the subject is one of the least satisfactory. Prof. Baird's excellent treatise On the Distribution and Migrations of North American Birds has been before adverted to. In giving this abstract the present writer wishes to state that he does not thereby express his agreement with all that it contains. Herr Palmén's views deserve the fullest attention from the truly scientific spirit in which they are put forward, but some of the details on which they are founded seem to require correction. xplana ons agnetism. tory Wagtail will build her nest in the accustomed spot, Dr von Middendorff (op. cit. p. 9), from the conclusions he has drawn, as before mentioned, as to the spring-movefered:- ment of all birds in the Russian Empire being towards the Taimyr Peninsula, the seat of one of the magnetic poles, has suggested that the migrating Bird is always aware (he does not sufficiently explain by what means) of the situation of this point, and thus knows how to steer its course. Not only is this hypothesis unsupported by any considerations known to the writer, but it is not at all borne out by the observed facts of Migration in North America, where Birds as has been shewn by Professor Baird (op. cit. p. 347) do not migrate in the direction of the magnetic pole. stinct. Other authors there are who rely on what they call "instinct" as an explanation of this wonderful faculty. This with them is simply a way of evading the difficulty before us, if it does not indeed remove the question altogether from the domain of scientific inquiry. Rejecting such a mode of treatment, Herr Palmén meets it in a much 1 Absolute proof of the identity of the particular birds is of course wanting, but if that objection be raised the circumstance becomes still more puzzling, for then we have to account for some mode of communicating precise information by one bird to another. 2 It has occurred indeed as a straggler in about a dozen instances Mr Gätke, to whom ornithologists are so deeply indebted for his long | fairer spirit. He asserts (op. cit. p. 195) that migrants are There yet remain a few words to be said on what may Excep 3 Manual d'Ornithologie, iii. Introd. p. xliii. note. Pallas's tion of light did not exist, for Lord Lilford has recorded 4 how that once at Corfu he was startled by an uproar as if all the feathered inhabitants of the great Acherusian Marsh had met in conflict overhead, but he could form no conception of what birds produced the greater part of it. SONG. they shift from place to place in its quest, and may thus | find an easy way of accounting for their uncertain appearNutcracker. ance. The great band of Nutcrackers (Nucifraga caryocatactes) which in the autumn of 1844 pervaded Western and Central Europe' may also have been actuated by the same motive, but we can hardly explain the roaming of all Waxwing. other Birds so plausibly. The inroads of the Waxwing (Ampelis garrulus) have been the subject of interest for more than 300 years, and by persons prone to superstitious auguries were regarded as the forerunners of dire calamity. Sometimes years have passed without its being seen at all in Central, Western, or Southern Europe, and then perhaps for two or three seasons in succession vast flocks have suddenly appeared. Later observation has shown that this species is as inconstant in the choice of its summer- as of its winter-quarters, and though the cause of the irregularity may possibly be of much the same kind as that just sug-ing to his art, but strains which in all countries and in all gested in the case of the Crossbill, the truth awaits further investigation.2 One of the most extraordinary events known to ornithologists is the irruption into Europe in 1863 of Pallas's Sand-Grouse (Syrrhaptes paradoxus). Of this Bird, hitherto known only as an inhabitant of the Tartar steppes, a single specimen was obtained at Sarepta on the Volga in the winter of 1848. In May 1859 a pair is said to have been killed in the Government of Vilna on the western borders of the Russian Empire, and a few weeks later five examples were procured, and a few others seen, in Western Europe-one in Jutland, one in Holland, two in England, and one in Wales. In 1860 another was obtained at Sarepta; but in May and June 1863 a horde computed to consist of at least 700 individuals overran Europe-reaching Sweden, Norway, the Faroes, and Ireland in the north-west, and in the south extending to Sicily and almost to the frontiers of Spain. On the sandhills of Jutland and Holland some of these birds bred, but war was too successfully waged against the nomades to allow of their establishing themselves, and a few survivors only were left to fall to the gun in the course of the following winter and spring. In the summer of 1872, another visitation to Great Britain was reported, but if it really took place it must have been that of a very small number of birds, and it was not observed on the Continent. Speculation has amused itself by assigning causes to these movements but the real reason remains in doubt. Nocturnal concourse 3 We cannot quit the subject of Migration, however, without referring to the wonderful assemblages of Birds which of migrants. have in various places been time and again noticed by night. Towards the close of summer, in dark, cloudy, and still weather, it not unfrequently happens that a vast and, to judge from their cries, heterogeneous concourse of Birds may be heard hovering over our large towns. The practical ornithologist will recognize the notes of Plover, Sandpiper, Tern, and Gull, now faint with distance and then apparently close overhead, while occasionally the stroke of a wing may catch his ear, but nothing is visible in the surrounding gloom. Sometimes but a few fitful wails are heard, of which only an expert listener will know the meaning. At others the continuous Babel of sounds will ensure the attention of the most incurious. It is supposed that these noises proceed from migrating birds, which, having lost their way, are attracted by the glare of the street lamps, but far too little has been observed to remove the obscurity that in a double sense surrounds them and to enable us to come to any definite conclusion. It must be added also that such a concourse has been noticed where the fascina 1 Bull. de l'Acad. de Bruxelles, xi. p. 298. 2 Cf. Yarrell, Brit. Birds, cd. 4, i. pp. 524-532. Ibis, 1864, pp. 185-222. A few additional particulars which have since become known to the writer are inserted above. 5 Leaving then the subject of Migration, the next important part of the economy of Birds to be considered is perhaps their Song—a word, however, in a treatise of this kind to be used in a general sense, and not limited to the vocal sounds uttered by not more than a moiety of the feathered races which charm us by the strains they pour from their vibrating throat,―strains indeed denied by the scientific musician to come under cognizance as appertainages have conveyed a feeling of true pleasure to the human hearer, and strains of which by common consent the Nightingale is the consummate master. It is necessary in a philosophical spirit to regard every sound made by a Bird under the all-powerful influence of love or lust as a "Song." It seems impossible to draw any but an arbitrary line Variety between the deep booming of the Emeu, the harsh cry of Song. the Guillemot (which, when proceeding from a hundred or a thousand throats, strikes the distant ear in a confused murmur like the roar of a tumultuous crowd), the plaintive wail of the Plover, the melodious whistle of the Widgeon," the Cock's shrill clarion," the scream of the Eagle, the hoot of the Owl, the solemn chime of the Bellbird, the whip-cracking of the Manakin, the Chaffinch's joyous burst, or the hoarse croak of the Raven, on the one hand, and the bleating of the Snipe or the drumming of the Ruffed Grouse, on the other. Innumerable are the forms which such utterances take. In many birds the sounds are due to a combination of vocal and instrumental powers, or, as in the cases last mentioned, to the latter only. But, however produced-and of the machinery whereby they are accomplished there is not room here to speakall have the same cause and the same effect. The former has been already indicated, and the latter is its consummation. Almost coinstantaneously with the hatching of the Nightingale's brood, the song of the sire is hushed, and the notes to which we have for weeks hearkened with rapt admiration are changed to a guttural croak, expressive of alarm and anxiety, inspiring a sentiment of the most opposite character. No greater contrast can be imagined, and no instance can be cited which more completely points out the purpose which "Song" fulfils in the economy of Purpose the bird, for if the Nightingale's nest at this early time be Song. destroyed or its contents removed, the cock speedily recovers his voice, and his favourite haunts again resound to his bewitching strains. For them his mate is content again to undergo the wearisome round of nest-building and incubation. But should some days elapse before disaster befalls their callow care, his constitution undergoes a change and no second attempt to rear a family is made. It would seem as though a mild temperature, and the abundance of food by which it is generally accompanied, prompt the physiological alteration which inspires the males of most birds to indulge in the "Song" peculiar to them. Thus after the annual moult is accomplished, and this is believed to be the most critical epoch in the life of any bird, cock Thrushes, Skylarks, and others begin to sing, not indeed with the jubilant voice of spring but in an 4 lbis, 1865, p. 176. The true cause of this sound has been much discussed, but Herr Meves's explanation (Proc. Zool. Soc. 1858, p. 302), based on experiment, seems to be correct, though it is far from being generally accepted. lestures kin to ong. f nests. uncertain cadence which is quickly silenced by the supervention of cold weather. Yet some birds we have which, except during the season of moult, hard frost, and time of snow, sing almost all the year round. Of these the Redbreast and the Wren are familiar examples, and the Chiffchaff repeats its two-noted cry, almost to weariness, during the whole period of its residence in this country.1 Akin to the "Song" of Birds, and undoubtedly proceeding from the same cause, are the peculiar gestures which the males of many perform under the influence of the approaching season of pairing, but these again are far too numerous here to describe with particularity. It must suffice to mention a few cases. The Ruff on his hillock in a marsh holds a war-dance. The Snipe and some of his allies mount aloft and wildly execute unlooked-for evolutions almost in the clouds. The Woodcock and many of the Goatsuckers beat evening after evening the same aerial path with its sudden and sharp turnings. The Ring-Dove rises above the neighbouring trees and then with motion less wings slides down to the leafy retreat they afford. The Capercally and Blackcock, perched on a commanding eminence, throw themselves into postures that defy the skill of the caricaturist-other species of the Grouse-tribe assume the strangest attitudes and run in circles till the turf is worn bare. The Peacock in pride spreads his train so as to shew how nearly akin are the majestic and the ludicrous. The Bower-bird, not content with his own splendour, builds an arcade, decked with bright feathers and shining shells, through and around which he paces with his gay companions. The Larks and Pipits never deliver their song so well as when seeking the upper air. Rooks rise one after the other to a great height and, turning on their back, wantonly precipitate themselves many yards towards the ground, while the solemn Raven does not scorn a similar feat, and, with the tenderest of croaks, glides supinely alongside or in front of his mate.2 NIDIFICATION. Following or coincident with the actions just named, and countless more besides, comes the real work of the breeding-season, to which they are but the prelude or the arieties accompaniment. Nidification is with most birds the beginning of this business; but with many it is a labour that is scamped if not shirked. Some of the Auk tribe place their single egg on a bare ledge of rock, where its peculiar conical shape is but a precarious safeguard when rocked by the wind or stirred by the thronging crowd of its parents' fellows. The Stone-Curlew and the Goatsucker deposit their eggs without the slightest preparation of the soil on which they rest; yet this is not done at haphazard, for no birds can be more constant in selecting, almost to an inch, the very same spot which year after year they choose for their procreant cradle. In marked contrast to such artless care stand the wonderful structures which others, such as the Tailor-bird, the Bottle-Titmouse, or the Fantail-Warbler build for the comfort or safety of their young. But every A curious question, which has as yet attracted but little attention, is whether the notes of the same species of Bird are in all countries alike. From his own observation the writer is inclined to think that it is not, and that there may exist "dialects," so to speak, of the song. (Cf. Gloger, Jour. für Orn. 1859, p. 398.) 2 No comprehensive account of the Song of Birds seems ever to have been written. The following may be cited as the principal treatises on the subject-Barrington, Phil. Trans. 1773, pp. 249-291; KenLedy, N. Abhandl. baier. Akad. (Phil. Abhandl.) 1797, p. 169; Black wall, Mem. Lit. and Phil. Soc. Manch. 1824, pp. 289-323; Savart, (Froriep's) Notizen u. s. w., 1826, pp. 1-10, 20-25; Brehm and Hansmann, Naumannia, 1855, pp. 54-59, 96-101, 181-195, and Journ. für Orn. 1855, pp. 348-351, 1856, pp. 250-255. The notes of many of our common Birds are musically expressed by Mr Harting, Birds of Middlesex (London: 1866). variety of disposition may be found in the Class. The Apteryx seems to entrust its abnormally big egg to an excavation among the roots of a tree-fern; while a band of female Ostriches scrape holes in the desert-sand and therein promiscuously dropping their eggs cover them with earth and leave the task of incubation to the male, who discharges the duty thus imposed upon him by night only, and trusts by day to the sun's rays for keeping up the needful, fostering warmth. The Megapodes raise a huge hotbed of dead leaves wherein they deposit their eggs and the young are hatched without further care on the part of either parent. Some of the Grebes and Rails seem to avail themselves in a less degree of the heat generated by vegetable decay, and dragging from the bottom or sides of the waters they frequent fragments of aquatic plants form of them a rude half-floating mass which is piled on some growing water-weed-but these birds do not spurn the duties of maternity. Many of the Gulls, Sandpipers, and Plovers lay their eggs in a shallow pit which they hollow out in the soil, and then as incubation proceeds add thereto a low breastwork of haulm. The Ringed Plover commonly places its eggs on shingle, which they so much resemble in colour, but when breeding on grassy uplands it paves the nest-hole with small stones. Pigeons mostly make an artless platform of sticks so loosely laid together that their pearly treasures may be perceived from beneath by the inquisitive observer. The Magpie, as though self-conscious that its own thieving habits may be imitated by its neighbours, surrounds its nest with a hedge of thorns. Very many birds of almost every group bore holes in some sandy cliff, and at the end of their tunnel deposit their eggs with or without bedding. Such bedding, too, is very various in character; thus, while the Sheldduck and the Sand-Martin supply the softest of materials, the one of down from her own body, the other of feathers collected by dint of diligent search, the Kingfisher forms a couch of the undigested spiny fish-bones which she ejects in pellets from her own stomach. Other birds, as the Woodpeckers, hew holes in living trees, even when the timber is of considerable hardness, and therein establish their nursery. Some of the Swifts secrete from their salivary glands a fluid which rapidly hardens as it dries on exposure to the air into a substance resembling isinglass, and thus furnish the "edible birds' nests" that are the delight of Chinese epicures. In the architecture of nearly all the Passerine birds, too, some salivary secretion seems to play an important part. By its aid they are enabled to moisten and bend the otherwise refractory twigs and straws and glue them to their place. Spiders' webs also are employed with great advantage for the purpose last mentioned, but perhaps chiefly to attach fragments of moss and lichen so as to render the whole structure less obvious to the eye of the spoiler. The Tailor-bird deliberately spins a thread of cotton and therewith stitches together the edges of a pair of leaves to make a receptacle for its nest. Beautiful too is the felt fabricated of fur or hairs by the various species of Titmouse, while many birds ingeniously weave into a compact mass both animal and vegetable fibres, forming an admirable non-conducting medium which guards the eggs from the extremes of temperature outside. Such a structure may be open and cup-shaped, supported from below as that of the Chaffinch and Goldfinch, domed like that of the Wren and Bottle-Titmouse, slung hammock-wise as in the case of the Golden-crested Wren and the Orioles, or suspended by a single cord as with certain Grosbeaks and Hummingbirds. Under such circumstances it is even sometimes needful to balance the nest lest the weight of the growing young should destroy the equipoise and, precipitating them. on the ground, dash the hopes of the parents, and compensation in such cases is applied by loading the opposite |