Oology may be said to be the latest of the sciences; and although perhaps not a very profound one, it is certainly among the most interesting. Those who are not ornithologists, or specially interested in natural history, can have but little idea of the progress made of late in all that pertains to the nidification of British birds. Expensive and elaborately illustrated treatises have been written on the subject; naturalists have spent thousands of pounds in tracking birds to their breeding haunts; and some of the best scientific workers of the day are devoting their lives to this and the kindred subject of migration. Then again city "naturalists" have their continental collectors, and are building up quite a commerce about the subject. The money value of a complete set of clutches of eggs of British birds is about £200, although more than double this sum would be given for eggs taken within the British Islands. Of course a great number of birds do not breed and never have bred here; for whilst the number of species comprising the home list is three hundred and sixty-seven, only about two hundred breed within our shores.

Not a few of the eggs of British birds are worth more than their weight in gold, whilst those of certain species which are supposed to have become extinct bring quite fabulous prices. A well-marked pair of golden eagle's eggs have been known to fetch £25. The market value of an egg of the swallow-tailed kite is three guineas, of Pallas's sand-grouse thirty shillings, while ten times that amount was recently offered for an egg of this Asiatic species taken in Britain. On the other hand, the eggs of certain of the social breeding birds are so common in their season as to be systematically collected for domestic purposes. And this in face of the fact that many of them are remarkable alike for size, shape, and beauty of colouring. This applies particularly to the guillemot, whose eggs are often remarkably handsome. As a rule the colour of these is bluish green, heavily blotched, and streaked with brown or black; and the form that of an elongated handsome pear. The guillemot is one of our commonest cliff-birds, and is found in greatest abundance at Flamborough Head. The eggs are systematically gathered by men who are let down the rocks in ropes. They traverse the narrowest ledges, placing the eggs which they gather daily in baskets fastened round their shoulders. The guillemot makes no nest, lays but one egg, and incubation lasts about a month. The birds sit upright, and when suddenly alarmed, as by the firing of a gun, the eggs fall in showers into the sea. Most of those collected at Flamborough are sent to Leeds, where the albumen is used in the preparation of patent leather; whilst the eggs taken on Lundy are used at Bristol in the manufacture of sugar. At the British breeding-stations of the gannet, or Solan goose, thousands of birds breed annually, though in numbers less than formerly. In this case the young birds, not the eggs, are taken; and on North Barra from two thousand to three thousand birds are captured in a season. The collector kills the gannets as they are taken from the nests, and they are then thrown into the sea beneath, where a boat is in waiting to pick them up. In the Faroes the people keep January 25 as a festival in consequence of the return of the birds.

The difference in size and colour which the eggs of different birds exhibit is even more apparent than the great diversity of shape. The giant eggs of wild swans and geese, or the extinct great auk, are tremendous when compared with those of the warblers and titmice; while the egg of the golden-crested wren is smaller still. This, the smallest British bird, is a mere fluff of feathers, and weighs only eighty grains. The relative sizes of the eggs named are as a garden-pea to a cocoanut. Another interesting phase of the subject is the number of eggs laid by different species. The Solan goose, guillemot, cormorant, shag, puffin, and others lay but one egg; whilst some of the tiny tits have been known to produce as many as twenty. In this respect the game-birds and wild-fowl are also prolific, and a partridge's nest containing from fifteen to twenty eggs is not at all an uncommon occurrence. Where a greater number of eggs than this is found, it is probable that two females have laid in the same nest. Certain species, again, habitually bred once, twice, or thrice a season; whilst others less prolific have but a single egg, and lay but once during the year.

Almost as interesting as the eggs they contain are the nests themselves. Birds of the plover kind almost invariably deposit their eggs in a mere depression in the ground; while many of the shore-haunting birds lay theirs in sand and shingle—often upon the bare stones. The present writer once found a ringed dotterell's nest on a bank of dÉbris, the eggs being stuck right on end, and absolutely resembling the drift stuff. The lapwing's eggs invariably have their smaller ends pointing inward. This bird is an early breeder, and eggs may often be found by the middle of March. It is these first clutches that fetch such fancy prices in the market, as much as fifteen shillings having been paid for a single egg. So anxious are the poulterers to obtain these that one of them expressed himself to the effect that if he were assured of having the first ten eggs he would not hesitate to give five pounds for them. Among birds the ground builders are the most primitive architects; but their very obtrusiveness certainly aids them to escape detection. Partridges and pheasants almost invariably lay their olive eggs upon dead oak-leaves, and, moreover, cover them when they leave the nest. The red speckled eggs of the grouse are very much of the colour of the heather, as are those of wild ducks to the green reeds and rushes. The nest of the cushat, or woodpigeon, consists of a mere platform of sticks, and the eggs may almost always be seen through the interstices of the crossed twigs. The goatsucker makes no nest, but lays its eggs among burning bits of limestone on the sides of the fells; and that of the golden plover is equally non-existent. Among tree builders the jay is slovenly and negligent, while the scarlet bull-finch is equally careless. Hawks, falcons, and birds of the crow kind construct substantial platforms of sticks; though the crafty magpie is an exception, and constructs a domed nest. The reason for this is not easy to understand, but, being an arrant thief itself, the pie is perhaps suspicious of birddom in general. The pretty water-ouzel, or dipper, also builds a domed nest, which as a rule resembles a great boss of bright green moss. The domicile of the wren is simply a small edition of the last, and often contains as many as seven or eight eggs. A curious habit may frequently be observed in connection with the wren's nesting, that of beginning several structures and then abandoning them. Nests, too, are not unfrequently built and occupied in winter, quite a colony of wrens at this time huddling together for the sake of warmth. Mr. Weir watched a pair at work building, and found that although the nest was commenced at seven o'clock in the morning it was completed the same night. There can be no question as to the clever adaptation of the wren's nest to its surroundings. When it is built in a mossy bank its exterior is of moss, often with a dead leaf on the outside. A nest which was against a hayrick was composed outwardly of hay; while another, in a raspberry bush, was wholly composed of the leaves of that plant.

Probably the only hang-nests of British birds are those of the gold-crest, reed-warbler, and long-tailed titmouse. The first is usually hung among the long, trailing tassels of the pine, where it is most difficult to detect. It is quite one of the prettiest examples of bird architecture, and is thickly felted with wool, feathers, and spiders' webs. The eggs are white, speckled with red. Montague kept a brood of eight nestlings in his room, when he found that the female bird fed them upon an average thirty-six times an hour, and that this was continued sixteen hours a day. Besides being built in pines, the nests are sometimes attached to yews and cedars. The cradle of the reed-warbler is invariably hung upon the stalks of reeds, rushes, and other aquatic plants; and the whole structure is often swayed about so much by the wind as not unfrequently to touch the water. The bottle-shaped nest of the long-tailed tit is almost as remarkable as its builder. It is exquisite alike in form and material, and its interior is a perfect mass of feathers. In one nest alone were found two thousand three hundred and seventy-nine, chiefly those of the pheasant, wood-pigeon, rook, and partridge. Sometimes a great many eggs are found in the nest of the long-tailed titmouse—as many as twenty, it is stated—and these are white, speckled, and streaked with red.

The colours of eggs in relation to birds and the site of their nests is an exceedingly interesting phase of the philosophy of the subject. It is found as an almost invariable rule that birds which lay white eggs nest in holes as a means of protection. The high-flying, loud-screeching swift is an instance of this. So is the burrowing sand-martin, the kingfisher, the shell-duck, and the woodpecker; also the puffin and the stock-dove, which breed in disused rabbit burrows. All these lay white eggs.

The hole which the swift selects is usually in a high building; while the delicate bank-swallows drill their holes in river banks or sandholes. The eggs of the kingfisher are perhaps the most beautiful of all. They are beautifully round, delicately white, glossy, and suffused with an exquisite rosy flush. For breeding, the kingfisher either drills a hole for itself or occupies that deserted by some small rodent. The seven or eight eggs are placed at the end of the burrow, upon a mass of dry fish bones ejected by the bird. The nest is so friable that it is almost impossible to remove it, and at one time it was said that the authorities at the British Museum were prepared to pay one hundred pounds for an absolutely perfect nest of the kingfisher.

The sheld is the largest and handsomest of British ducks. It invariably breeds in a burrow on a plateau commanding the sea, and when approaching its nest plumps right down at the mouth of the hole. Its creamy eggs are large and round; and for a day or so after the young are hatched they are kept underground. Emerging from their retreat, they are immediately led or carried down to the tide. The young seem to be able to smell salt water, and will cover miles to gain it. An interesting fact anent another of our British ducks centres about the golden-eye, an exquisite study in black and white, the back of the neck and head being burnished with violet and green. A trait which the golden-eye has is its almost invariable habit of nesting in holes in trees—remarkable in the case of a duck—so that the Laps place darkened boxes by the sides of rivers and lakes for the ducks to lay in. Often as many as a dozen eggs are found, and the nests are lined with the soft down of the birds. The golden-eye has been seen to transport its young to the water from a considerable altitude. While botanising by the side of a lake, where these beautiful birds breed in great numbers, a Lap clergyman observed one of them drop into the water, and at the same time an infant duck appeared. After watching awhile and seeing the old bird fly to and from the nest several times, he made out that the young bird was held under the bill, but supported by the neck of the parent.

All the British woodpeckers bear out the theory already stated. They lay glossy white eggs, and their nests, (if the touchwood upon which their eggs are deposited can be so called,) are always built in holes in growing wood or decayed timber. The stock-dove, one of our pretty wild pigeons, nests in colonies in rabbit-burrows, as does the brown owl. When ferreting for rabbits the writer has put both these birds out of the holes instead of their rightful owners. The nuthatch is yet another bird which upholds the same rule, and whose case is peculiarly interesting. It not only lays purely white eggs in holes in trees, but if the hole for ingress and egress is one whit too large it is plastered up by the industrious bird until it barely admits the body of the clever little architect.

The cuckoo is quite a Bohemian among birds, and it is doubtless owing to its vagrant habits that there yet remain several points in its life-history which have to be cleared up. The most interesting of these questions are those which relate to its nesting and nidification. It was once thought that the cuckoo paired, but it is now known that the species is polygamous. The number of hens that constitute a harem is not known, but from the number of bachelor birds the males must greatly predominate over the females. Dissection conclusively proves that each female lays a series of eggs, and that these occur in the ovary in widely different stages of maturity. The older naturalists thought that the cuckoo laid its eggs actually in the nests of other birds, but it is now known that it conveys them thither in its bill. The egg of the cuckoo has been found in the nests of sixty different species, several of which are exceedingly small, and moreover domed. Among the sixty nests patronised were the unlikely ones of the butcher-bird, jay, and magpie—all either bird or egg destroyers. This may seem to reflect on the cuckoo's stupidity; and the bird certainly exhibits deplorable ignorance of the fitness of things when it deposits its egg in the nest of the diminutive goldcrest or the cumbersome one of the cushat. A goldcrest might conveniently be stowed away in the gape of a young cuckoo without the latter detecting that the morsel was much more than a normal supply. The nests in which the eggs of cuckoos are most frequently found are those of the meadow-pipit, hedge-sparrow, and reed-warbler. Now the eggs of these birds vary to a very considerable degree; and the question arises whether the cuckoo has the power of assimilating the colour of its egg to those among which it is to be deposited. Certain eminent continental ornithologists claim that this is so, but facts observed in England hardly bear out the conclusion. Brown eggs have been found among the blue ones of the hedge-sparrow, redstart, wheatear; among the green and grey ones of other birds; and the purely white ones of the wood-pigeon and turtle-dove. The cuckoo's egg is brown, and it must be admitted that the great majority of the nests which it patronises contain eggs more or less nearly resembling its own. There is a general family likeness about those laid by the bird, not only in the same clutch, but from year to year. Admitting that the eggs of the cuckoo as a species vary more than those of other birds, it is yet probable that the same female invariably lays eggs of one colour. This can only be surmised by analogy, though the one fact bearing on the question is where two cuckoo's eggs were found in the same nest, and which differed greatly. More might have been learnt from the incident had it been known for certain whether the eggs were laid by the same or different birds. There is a general tendency in the habits of animals to become hereditary, and it seems not unreasonable to suppose that a cuckoo which has once laid its egg in the nest of any particular species should continue to do so, and that its offspring also should continue the practice in after years. A possibility with regard to the cuckoo is that it is not so destitute of maternal instinct as is generally supposed, and that it occasionally hatches its own eggs. It is certain that a female has been seen with her breast destitute of feathers, and with young cuckoos following her and clamouring to be fed. Some other species of the genus nearly akin to our own bird are quite normal in their nesting habits, and I here suggest that, under certain circumstances, our English cuckoo may be so likewise.

The dotterel is one of the most interesting of British birds. It is a summer visitant, and breeds upon the tops of the highest mountains. It is every year decreasing as a species in consequence of the persistency with which it is hunted down for its feathers; these are used for dressing flies. I have found it breeding upon Skiddaw, Sea Fell, and Helvellyn, though not since the year 1884. Part of the interest which attaches to the bird arises from the fact of its extremely local distribution, the mountains named being perhaps the only ones on which it is known to breed in this country. Hewitson, the eminent ornithologist, spent five consecutive seasons in looking for a dotterel's nest; and it was upon Great Robinson and the Hindsgarth range that he ultimately found its eggs. The large price offered for these has acted as a prize for the dotterel's extermination by the shepherds; and some years ago a quarryman had a dog which was trained to find the nests. Owing to the great number of trout streams in the Lake district, angling is general; and, as has been said, the dotterel's decrease is due entirely to the great demand for skins. The birds are mainly shot either on their spring or autumnal migration, and at the former season the grandfather of the present writer upon one occasion bagged seventeen birds in a morning.

Although eagles are now more than rare in Britain, there was a time when they bred among the crags of Cumbria. Gray and Sir Humphrey Davy watched the eagles in their eyries, and the former tells how he saw them robbed of their young. To say nothing of the carnage made on hares, grouse, and waterfowl, these birds during the breeding season destroyed a lamb daily. It is no wonder that the farmers, shepherds, and dalesfolk were careful to plunder the eyries, though this was not done without very considerable risk. In one case a man was lowered down the rocks a distance of fifty fathoms, and during the descent he had to protect himself against the attacks of the parent birds. Year by year the eggs or eaglets were taken, and as their presence was injurious to the interests of the farmers, the latter were willing to pay for their extermination. If the nest contained young birds, these were to be the cliff-climber's remuneration; but if eggs, every neighbouring farmer paid for each egg five shillings. The nests were formed of the branches of trees, and lined with coarse grass and bents that grew on the neighbouring rocks. On the eagles being so frequently robbed of their young, they became unsettled and removed from crag to crag. On one mighty escarpment more inaccessible than the rest they nested for fourteen consecutive years. These eagles and their progenitors had probably bred in the near vicinity for centuries; and the conservatism of birds—especially birds of prey—is quite remarkable. Of this two instances may be given. In Cotheca Wolleyana it is recorded that a peregrine falcon's nest on a hill called Arasaxa, in Finland, is mentioned by the French astronomer Maupertius as having been observed by him in 1736. In 1799 it was rediscovered by SkjÖldebrand and Acerti. Wolley himself found it tenanted in 1853, and by examining the remains of a young bird lying near the nest, proved that it belonged to this species. It is probable, therefore, that this particular eyrie had been used by the same species of falcon for one hundred and seventeen years.

The following is another instance, hardly less remarkable, though having reference to an altogether different kind of bird. The particular incident is well known to naturalists, and perhaps the latest rendering of it is that by the Nestor of British ornithology, Professor Newton. He says: "When the blue titmouse has taken possession of a hole, she is not easily induced to quit it, but defends her nest and eggs with great courage and pertinacity, puffing out her feathers, hissing like a snake, and trying to repel the fingers of the intruder…. The branch containing the nest may even be sawn off and conveyed to a distance (a cruel experiment) without the mother leaving it, and cases have been known in which, when this has been done, she has still continued to sit on her eggs, hatch them, and rear her brood. With equal persistence will this species year after year use as a nursery the same hole, and a remarkable instance of this kind is on record. In 1779, according to one account, in 1785, according to another, it is said that a pair of these birds built their nest in a large earthenware bottle which had been left to drain in the branches of a tree in a garden at Oxbridge, in the township of Hartburn, near Stockton-on-Tees, and safely hatched their young. The bottle having been allowed to remain in the same position by the occupiers of the farm, then and still a family of the name of Callendar, was frequented for the same purpose and with a like result, until 1822, when, the tree becoming decayed, the bottle was placed in one near by, and the tenancy continued until 1851. In that year the occupiers of the farm omitted drawing out the old nest, as had been the constant practice before the breeding season, and in consequence the birds chose another place; but in 1852 they returned to the bottle, and have annually built in it, or in a second bottle, which has lately been placed close by it, up to the present year, 1873, with the exception of one season, when a pair of great titmice took possession of their inheritance. The intruders were shot, and the tenancy, it is hoped, will not be again disturbed."

Many birds show that they have the power of not only cleverly adapting themselves to circumstances in matters concerning their nesting, but that they are also equal to unforeseen accidents, which not unfrequently occur. From the secluded haunts and hideling habits of birds of the rail kind, it would hardly be imagined that they were endowed with much intelligence. Here is a striking instance, however, to the contrary. A pair of waterhens built their nest upon an ornamental piece of water of considerable extent, which was ordinarily fed from a spring, and into which another large pond was occasionally emptied. This upon one occasion was done while the female was sitting, and, as the nest had been built at low water, the sudden influx from the second pond caused the water to rise so rapidly as to threaten the destruction of the eggs. This the birds seemed aware of, and immediately took precautions against it. The gardener on the estate, knowing of the sudden rise of water, went to look after the nest, though quite expecting to find the eggs ruined. Instead of this he saw both birds busily engaged about the nest, and adding, with all possible despatch, fresh materials to the fabric to bring it above the impending flood. This they not only succeeded in doing, but it was observed that upon the first rush of water they had removed the eggs to a distance of some feet from the margin of the pool. In the meantime the nest rose rapidly in height, and when the water began to retire the eggs were brought back and placed in the nest. In a few days these were hatched, and the young were swimming with their parents about the pool. The nest plainly showed the formation of the old and new material, and testified to the instinct or reason of the bird architects. In this connection birds have been known to adapt their nests to changed forms of architecture; and almost innumerable little devices may be seen in individual nests tending to their special safety or protection. As an instance of adaptation to haunt it may be mentioned that in the north, buzzards and ravens invariably nest among the rocks of the crags, whilst in the south their nests are just as invariably found in trees.

Both the eggs and plumage of game birds offer interesting instances of this adaptation. The pencilled plumage of the snipe lying still in the brown marshes it is impossible to detect, although the birds get up at one's feet everywhere. The same may be said of the woodcock in the leaf-strewn woods, and of the nests and eggs of both species. The eggs of the wild-duck assimilate to the colour of the green reeds, and those of the lapwing to the ploughed field or the upland. The colour of the red grouse conforms very nearly to that of the purple heather among which it lies, as do the richly-speckled eggs. The partridge has a double protection. It is difficult to pick out her quiet brown plumage from a hedge-bottom so long as she remains still. She adopts the duns and browns and yellows of the dead leaves, among which she crouches. When she leaves her eggs she is careful to cover them with dead oak-leaves; but this seems almost superfluous, for there is no great contrast between the tint of the eggs and that of the leaves among which they lie. A hen pheasant lying in a bracken-bed is equally difficult to detect; and this applies particularly to all the young of the game birds just mentioned. The bright, dark eyes of birds and animals frequently betray them, as these are almost invariably large and prominent. A short-eared owl on a peat-moss I have mistaken for a clod of turf, and a gaunt heron with wind-fluttered feathers for drift stuff caught in the swaying branches of the stream. Another characteristic case of protective imitation is furnished by the nightjar or goatsucker. This night-flying bird, half owl, half swallow, rests during the day on bare bits of limestone on the fells. Its mottled plumage exactly corresponds with the grey of the stones, and its eggs, in colour like its plumage, are laid upon the bare ground without the slightest vestige of a nest—and again entirely resemble the stone.

It will be remarked that all the birds mentioned live much upon the ground, obtaining the principal part of their food therefrom, and that therefore they have need of special protection. Incubation in every case takes place on the ground; and just as the imitation of the plumage of the female bird is perfect, so will the fact tell upon the survival of the species. There is no such need of protection for tree builders, as these, for the most part, are out of the way of predatory animals. The chaffinch is by far the most abundant bird of our fields and woods; and there is one good reason why it should be so. It invariably covers its nest on the outside with dead lichens, like to those of the trunk against which it is built. Against boys and other predatory creatures the device succeeds admirably, and the chaffinch as a species flourishes vigorously. The wren constructs her nest of moss, placing it upon a mossy background so as to present no sharp contrasts. Sometimes she interweaves one or two dead oak-leaves, so as to render the deception more deceitful; and, from the number of wrens which abound, she evidently succeeds. Starlings and sparrows and jackdaws, which build in holes at a considerable elevation, and have therefore less need of protection, hang out straws and sticks and bits of wool and feather as impudent advertisements. Wheatears and such birds as build in low walls cannot afford to do this, but instead build neat nests leaving no trace without. Several of our leaf-warblers drag dead leaves to the outside of their nests, and a hundred others employ like ingenuities.

With regard to sexual colour, the dull summer plumage which characterises so many ground-breeding birds is all the more remarkable as they are the mates of males for the most part distinguished by unusual brilliancy. The few exceptions to this rule are of the most interesting character, and go eminently to prove it. In these exceptions it happens that the female birds are more brightly plumaged than the males. But in nearly the whole of the cases this remarkable trait comes out—that the male actually sits upon the eggs. Now this fact more than any other would seem to indicate that the protection afforded by obscure colouring is directly intended to secure the bird's safety during the most critical period of its life-history. And it has been seen that the law of protective colouring most influences those birds which breed on the ground. One remarkable instance of this may be given, that of the dotterel, a bird already mentioned. This is a species of our own avi-fauna, one which breeds on the summits of the highest mountains. Mr. Gould has remarked that dotterel have not unfrequently been shot during the breeding season with the breast bare of feathers, caused by sitting on the eggs; and the writer knows of his personal knowledge that the shepherds on the Cumbrian mountains occasionally kill dotterel on the actual nest, and that these almost invariably turn out to be males. In winter the colouring of the sexes is almost identical; but when the breeding season comes round the female dons a well-defined, conspicuous plumage, while it is found that the dull-coloured male alone sits upon the eggs. Mr. Wallace has pointed out that bee-eaters, motmots, and toucans—among the most brilliant of tropical birds—all build in holes in trees. In each of these cases there is but little difference in the plumage of the sexes, and where this is so the above rule is almost invariable. Again, our native kingfisher affords an illustration. The orange-plumaged orioles have pensile nests, which is a characteristic of the order to which they belong, most of the members of which are conspicuous. Bird enemies come from above rather than below, and it will be seen that the modifications referred to all have reference to the upper plumage.

In 1888 an egg of a great auk was sold for one hundred and sixty guineas, whilst more recently an egg of the same species fetched two hundred and twenty-five pounds; and although these may seem enormous sums to give for a relic, the transactions are not without others to keep them in countenance. Only a few years ago two eggs of the same kind fetched one hundred and one hundred and two guineas respectively; while the egg first named realised thirty-three pounds ten shillings a little over twenty years ago. At that time it was discovered, together with four others, packed away in a dust-covered box in the museum of the Royal College of Surgeons, these being sold in 1865. From this it would seem that in the ornithological market the complete shell of a great auk's egg is worth nearly one hundred and seventy pounds, and a broken one only seventy pounds less. It will be seen that the purchase of one of these may be a good investment; and what a mine of wealth a great auk that was a good layer might prove to its fortunate possessor can only be conjectured. At the present time the number of eggs of this species known to exist is sixty-six, twenty-five of which are in museums and forty-one in private collections. Of the total number forty-three are retained in Great Britain. When a bird becomes so rare that the individual remains can be counted, the same may be taken to be practically extinct as a species. The great auk has pursued a policy of extinction for the past two or three centuries, until now, like the mighty moa and the dodo, it has ceased to exist. The great auk, or gare-fowl, was one of those birds which, from long disuse, had lost at once the power of flight and preservation. It was a great shambling bird, as large as a goose, and ill adapted to travel on land. How these things told against it may be inferred from the story of one Captain Richard Whitbourne, who writing of the discovery of Newfoundland in 1620, says that among the abundant water-fowl of these parts are penguins (great auks) "as bigge as geese, and flye not, for they have but a short wing, and they multiply so infinitely, upon a certain flat island, that men drive them from thence upon a boord, into their boats by hundreds at a time." This process of extinction went on in Iceland and elsewhere until about the middle of the present century hardly any birds remained. The Icelanders robbed the auks of their eggs for domestic use, and upon one occasion the crew of a British privateer remained upon one of the skerries all day killing many birds and treading down their eggs and young. This went on until the last birds were taken, and there is but the faintest hope that it may yet linger on in the inaccessible North. Although awkward, and travelling with the greatest difficulty on land, the great auk was perfectly at home in the water, and travelled both upon and under the surface with the rapidity of a fish. The time of haunting the land was during the breeding season, in early summer. At this period the auk resorted to the rocks, in the dark recesses of which the females deposited one large egg—large even for the size of the bird. These had a whitish-green ground, streaked with brown, and nearly five inches in length.