of a great variety of small birds. I have known its egg intrufted to the care of the hedge-fparrow, the water-wagtail, the titlark, the yellow-hammer, the green linnet, and the whinchat. Among thefe it generally selects the three former; but fhews a much greater partiality to the hedge-fparrow than to any of the reft: therefore, for the purpose of avoid ing confufion, this bird only, in the fol. lowing account, will be confidered as the fofter-parent of the cuckoo, except in inftances which are particularly specified. The hedge-fparrow commonly takes up four or five days in laying her eggs. During this time, (generally after she has laid one or two), the cuckoo contrives to depofit her egg among the reft, leaving the future care of it entirely to the hedgefparrow. This intrufion often occafions fome difcompofure; for the old hedgefparrow at intervals, whilft fhe is fitting, not unfrequently throws out fome of her own eggs, and sometimes injures them in fuch a way that they become addle; fo that it more frequently happens, that only two or three hedge-fparrow's eggs are hatched with the cuckoo's than otherwise but whether this be the cafe or not, the fits the fame length of time as if no foreign egg had been introduced, the cuckoo's egg requiring no longer ineubation than her own. However, I have never seen an instance where the hedge-fparrow has either thrown out or injured the egg of the cuckoo,

When the hedge-fparrow has fat her ufual time, and difengaged the young cuckoo and fome of her own offspring from the shell, her own young ones, and any of her eggs that remain unhatched, are foon turned out, the young cuckoo remaining poffeffor of the neft, and fole object of her future care. The young birds are not previously killed, nor are the eggs demolished; but all are left to perifh together, either entangled about the bush which contains the neft, or lying on the ground under it.

The early fate of the young hedgefparrows is a circumftance that has been noticed by others, but attributed to wrong caufes. A variety of conjectures have been formed upon it. Some have fuppofed the parent cuckoo the author of their deftruction; while others, as erroneously, have pronounced them fmothered by the difproportionate fize of their fellow-neftling. Now the cuckoo's egg being not much larger than the hedgefparrow's (as I fhall more fully point out

hereafter), it neceffarily follows, that at firft there can be no great difference in the fize of the birds juft burft from the shell. Of the fallacy of the former affertion allo I was fome years ago convinced, by having found that many cuckoo's eggs were hatched in the nefts of other birds after the old cuckoo had disappeared; and by feeing the fame fate then attend the neftling fparrows as during the appearance of old cuckoos in this country. But, before I proceed to the facts relating to the death of the young sparrows, it will be proper to lay before you fome examples of the incubation of the egg, and the rearing of the young cuckoo; fince even the well known fact, that this bufinefs is intrufted to the care of other birds, has been controverted by an author [Daines Barrington] who has lately written on this fubject; and fince, as it is a fact fa much out of the ordinary course of nature, it may ftill probably be disbelieved by others.

I. The titlark is frequently selected by the cuckoo to take charge of its young one; but as it is a bird lefs familiar than many that I have mentioned, its neft is not so often discovered. I have, nevertheless, had feveral cuckoo's eggs brought to me that were found in titlark's nefts; and had one opportunity of seeing the young cuckoo in the neft of this bird: I faw the old birds feed it repeatedly, and, to fatisfy myself that they were really titlarks, fhot them both, and found them to be fo.

II. A cuckoo laid her egg in a waterwagtail's neft in the thatch of an old cottage. The wagtail fat her usual time, and then hatched all the eggs but one; which, with all the young ones, except the cuckoo, was turned out of the neft. The young birds, confifting of five, were found upon a rafter that projected from under the thatch, and with them was the egg, not in the least injured. On examining the egg, I found the young wagtail it contained quite perfect, and just in such a state as birds are when ready to be difengaged from the shell. The cuckoo was reared by the wagtails till it was nearly capable of flying, when it was killed by an accident.

III. A hedge-fparrow built her neft in a hawthorn bush in a timber yard: after fhe had laid two eggs, a cuckoo dropped in a third. The sparrow continued laying, as if nothing had happened, till fhe had laid five, her usual number, and then fat.

June

June 20. 1786. On inspecting the nest I found, that the bird had hatched this morning, and that every thing but the young cuckoo was thrown out. Under the neft I found one of the young hedge fparrows dead, and one egg by the fide of the neft entangled with the coarse woody materials that formed its outfide covering. On examining the egg, I found one end of the fhell a little crack⚫ed, and could fee that the fparrow it contained was yet alive. It was then reftored to the neft, but in a few minutes was thrown out. The egg being again fufpended by the outfide of the neft, was faved a fecond time from breaking. To fee what would happen if the cuckoo was removed, I took out the cuckoo, and placed the egg containing the hedgefparrow in the neft in its ftead. The old birds, during this time, flew about the fpot, fhewing figns of great anxiety; but when I withdrew, they quickly came to the neft again. On looking into it in a quarter of an hour afterwards, I found the young one completely hatched, warm and lively. The hedge-fparrows were fuffered to remain undisturbed with their new charge for three hours (during which time they paid every attention to it) when the cuckoo was again put into the neft. The old fparrows had been fo much disturbed by these intrusions, that for fome time they fhewed an unwillingnefs to come to it: however, at length they came, and on examining the neft again in a few minutes, I found the young fparrow was tumbled out. It was a fecond time restored, but again experienced the fame fate.

From these experiments, and suppofing, from the feeble appearance of the young cuckoo juft difengaged from the fhell, that it was utterly incapable of displacing either the egg or the young fparrows, I was induced to believe, that the old fparrows were the only agents in this feeming unnatural bufinefs; but I afterwards clearly perceived the cause of this ftrange phænomenon, by difcovering the young cuckoo in the act of difplacing its fellow-neftlings, as the following rela tion will fully evince.

June 18. 1787, I examined the neft of a hedge-fparrow, which then contained a cuckoo's, and three hedge-fparrow's eggs. On inspecting it the day following, I found the bird had hatched, but that the neft now contained only a young cuckoo and one young hedge-fparrow. The neft

was placed fo near the extremity of a hedge, that I could diftinctly fee what was going forward in it; and, to my aftonishment, faw the young cuckoo, though fo newly hatched, in the act of turning out the young hedge-fparrow.

The mode of accomplishing this was very curious. The little animal, with the affiftance of its rump and wings, contrived to get the bird upon its back, and making a lodgement for the burden by elevating its elbows, clambered backward with it up the fide of the neft till it reached the top, where refting for a moment, it threw off its load with a jerk, and quite difengaged it from the neft. It remained in this fituation a short time, feeling about with the extremities of its wings, as if to be convinced whether the business was properly executed, and then dropped into the neft again. With the extremities of its wings I have often seen it examine, as it were, an egg and neftling before it began its operations; and the nice fenfibility which thefe parts appeared to poffefs feemed fufficiently to compenfate the want of fight, which as yet it was deftitute of. I afterwards put in an egg, and this, by a fimilar process, was conveyed to the edge of the neft, and thrown out. Thefe experiments I have fince repeated several times in different nefts, and have always found the young cuckoo difpofed to act in the fame manner. In climbing up the neft, it fometimes drops its burden, and thus is foiled in its endeavours; but, after a little refpite, the work is resumed, and goes on almoft inceffantly till it is effected. It is wonderful to fee the extraordinary exertions of the young cuckoo, when it is two or three days old, if a bird be put into the neft with it that is too weighty for it to lift out. In this ftate it feems ever reftlefs and uneasy. But this difpofition for turning out its companions begins to decline from the time it is two or three till it is about twelve days old, when, as far as I have hitherto feen, it ceafes. Indeed, the difpofition for throwing out the egg appears to cease a few days fooner; for I have frequently feen the young cuckoo, after it had been hatched nine or ten days, remove a nestling that had been placed in the neft with it, when it suffered an egg, put there at the fame time, to remain unmolested. The fingularity of its fhape is well adapted to these purposes; for, different from. other newly-hatched birds, its back from

A 2

the

the feapule downwards is very broad, with a confiderable depreffion in the middle. This depreffion feems formed by nature for the defign of giving a more fe cure lodgement to the egg of the hedgeSparrow, or its young one, when the young cuckoo is employed in removing either of them from the neft. When it is about twelve days old, this cavity is quite filled up, and then the back af. fumes the shape of neftling birds in general.

Having found that the old hedge-fparrow commonly throws out fome of her own eggs after her neft has received the cuckoo's, and not knowing how the might treat her young ones, if the young cuckoo was deprived of the power of difpoffeffing them of the neft, I made the following experiment.

July 9. A young cuckoo, that had been hatched by a hedge-fparrow about four hours, was confined in the neft in fuch a manner that it could not poffibly turn out the young hedge-sparrows which were hatched at the fame time, though it was almost inceffantly making attempts to effect it. The confequence was, the old birds fed the whole alike, and appeared in every refpect to pay the fame attention to their own young as to the young cuckoo, until the 13th, when the neft was unfortunately plundered.

The fmallness of the cuckoo's egg in proportion to the fize of the bird is a circumflance that hitherto, I believe, has efcaped the notice of the ornithologift. So great is the difproportion, that it is in general fmaller than that of the houfefparrow; whereas the difference in the fize of the birds is nearly as five to one. I have used the term in general, because eggs produced at different times by the fame bird vary very much in fize. I have found a cuckoo's egg fo light that it weighed only 43 grains, and one fo heavy that it weighed 55 grains. The colour of the cuckoo's eggs is extremely variable. Some, both in ground and penciling, very much resemble the housefparrow's; fome are indiftin&tly covered with bran-coloured spots; and others are marked with lines of black, refembling, in fome measure, the eggs of the yellow! hammer.

The circumftance of the young cuckoo's being defined by nature to throw out the young hedge-fparrows, feems to account for the parent-cuckoo's dropping her egg in the neft of birds fo fmall as thofe I have particularifed. If fhe were

to do this in the neft of a bird which produced a large egg, and confequently a large neftling, the young cuckoo would probably find an infurmountable difficulty in folely poffeffing the neft, as its exertions would be unequal to the labour of turning out the young birds. Befides, though many of the larger birds might have fed the neftling cuckoo very properly, had it been committed to their charge, yet they could not have fuffered their own young to have been facrificed, for the accommodation of the cuckoo, in fuch great number as the fmaller ones, which are fo much more abundant; for though it would be a vain attempt to calculate the numbers of nestlings deftroyed by means of the cuckoo, yet the flighteft, obfervation would be fufficient to convince us that they must be very large.

Here it may be remarked, that though nature permits the young cuckoo to make this great wafte, yet the animals thus deftroyed are not thrown away or rendered ufelef. At the feafon when this happens, great numbers of tender quadrupeds and reptiles are seeking provifion; and if they find the callow neftlings which have fallen victims to the young cuckoo, they are furnished with food well adapted to their peculiar ftate.

It appears a little extraordinary, that two cuckoo's eggs should ever be depofited in the fame neft, as the young one produced from one of them muft inevitably perish; yet I have known two inftances of this kind, one of which I shall relate.

June 17. 1787. Two cuckoos and a hedge-fparrow were hatched in the fame neft this morning; one hedge-fparrow's egg remained unhatched. In a few hours after, a conteft began between the cuckoos for the poffeffion of the neft, which continued undetermined till the next afternoon; when one of them, which was fomewhat fuperior in fize, turned out the other, together with the young hedgefparrow and the unhatched egg. This conteft was very remarkable. The combatants alternately appeared to have the advantage, as each carried the other feveral times nearly to the top of the neft, and then funk down again, oppreffed by the weight of its burden; till at length, after various efforts, the ftrongeft prevailed, and was afterwards brought up by the hedge-fparrows.

I come now to confider the principal matter that has agitated the mind of the

naturalift

naturalift refpecting the cuckoo why, like other birds, it should not build a neft, incubate its eggs, and rear its own young?

There is certainly no reason to be affigned from the formation of this bird why in common with others, it should not perform all these feveral offices; for it is in every respect perfectly formed for collecting materials and building a neft. Neither its external shape nor internal Atructure prevent it from incubation; nor is it by any means incapacitated from bringing food to its young. It would be needlefs to enumerate the various opinions of authors on this fubject from Ariftotle to the present time. Those of the ancients appear to be either visionary or erroneous; and the attempts of the moderns towards its investigation have been confined within very narrow limits; for they have gone but little farther in their refearches than to examine the conftitution and ftructure of the bird, and having found it poffeffed of a capacious ftomach, with a thin external covering, concluded that the preffure upon this part, in a fit ting pofture, prevented incubation. They have not confidered that many of the birds which incubate have ftomachs analogous to thofe of cuckoos: the ftomach of the owl, for example, is proportionably capacious, and is almoft as thinly covered with external integuments. Nor have they confidered, that the ftomachs of Deftlings are always much diftended with food; and that this very part, during the whole time of their confinement to the neft, fupports, in a great degree, the weight of the whole body; whereas, in a fitting bird, it is not nearly fo much preffed upon; for the breaft in that cafe fills up chiefly the cavity of the neft, for which purpofe, from its natural convexity, it is admirably well fitted.

Thefe obfervations, I prefume, may be fufficient to fhew that the cuckoo is not rendered incapable of fitting through a peculiarity either in the fituation or formation of the ftomach; yet, as a proof still more decifive, I shall lay before you the following fact.

In the fummer of 1786, I faw, in the neft of a hedge-fparrow, a cuckoo, which from its fize and plumage, appeared to be nearly a fortnight old. On lifting it up in the nest, I obferved two hedgefparrow's eggs under it. At first I fuppofed them part of the number which had been fat upon by the hedge fparrow with the cuckoo's egg, and that they had

become addle, as birds frequently fuffer fuch eggs to remain in their nefts with their young; but on breaking one of them I found it contained a living fœtus; fo that of courfe thefe eggs must have been laid feveral days after the cuckoo was hatched, as the latter now completely filled up the neft, and was by this peculiar incident performing the part of a fitting-bird.

At this time I was unacquainted with the fact, that the young cuckoo turned out the eggs of the hedge-sparrow; but it is reasonable to conclude, that it had loft the difpofition for doing this when thefe eggs were depofited in the neft.

Having under my infpection, in another hedge-fparrow's neft, a young cuc koo, about the fame fize as the former, I procured two wagtail's eggs which had been fat upon a few days, and had them immediately conveyed to the spot, and placed under the cuckoo. On the ninth day after the eggs had been in this fituation, the perfon appointed to fuperintend the neft, as it was some distance from the place of my refidence, came to inform me, that the wagtails were hatched. On going to the place, and examining the neft, I found nothing in it but the cuckoo and the shells of the wagtail's eggs. The fact, therefore, of the birds being hatched, I do not give you as coming immediately under my own eye; but the teftimony of the perfon appointed to watch the neft was corroborated by that of another witness.

To what cause then may we attribute the fingularities of the cuckoo? May they not be owing to the following circumftances? The fhort refidence this bird is allowed to make in the country where it is deftined to propagate its species, and the call that nature has upon it, during that short refidence, to produce a numerous progeny." The cuckoo's firft appearance here is about the middle of April. Its egg is not ready for incubation till fome weeks after its arrival, feldom before the middle of May. A fortnight is taken up by the fitting bird in batching the egg. The young bird generally continues three weeks in the neft before it flies, and the fofter-parents feed it more than five weeks after this period; fo that, if a cuckoo should be ready with an egg much fooner than the time pointed out, not a fingle neftling, even one of the earlieft, would be fit to provide for itfelf before its parent would be inftinc

tively

tively directed to feek a new refidence, and be thus compelled to abandon its young one; for old cuckoos take their final leave of this country the first week in July.

Had nature allowed the cuckoo to have ftaid here as long as fome other migra ting birds, which produce a fingle fet of young ones (as the fwift or nightingale, for example), and had allowed her to have reared as large a number as any bird is capable of bringing up at one time, thefe might not have been fufficient to have anfwered her purpose; but by fending the cuckoo from one neft to another, he is reduced to the fame ftate as the bird whofe neft we daily rob of an egg, in which cafe the ftimulus for incubation is fufpended. Of this we have a familiar example in the common domeftic fowl. That the cuckoo actually lays a great number of eggs, diffection feems to prove very decifively. Upon a comparifon I had an opportunity of making between the ovarium, or racemus vitellorum, of a female cuckoo, killed juft as fhe had begun to lay, and of a pullet killed in the fame ftate, no effential difference appeared. The uterus of each contained an egg perfectly formed, and ready for exclufion; and the ovarium exhibited a large clufter of eggs gradually advanced from a very diminutive fize, to the greateft the yolk acquires before it is received into the oviduct. The appearance of one killed on the third of July was very different. In this I could diftinctly trace a great number of the membranes which had discharged yolks into the oviduct; and one of them appeared as if it had parted with a yolk the preceding day. The ovarium ftill exhibited a clufter of enlarged eggs; but the moft forward of them was fcarcely larger than a mustard-feed.

I would not be understood to advance that every egg which fwells in the ovarium at the approach or commencement of the propagating feafon is brought to perfection: but it appears clearly, that a bird, in obedience to the dictates of her own will, or to fome hidden cause in the animal œconomy, can either retard or bring forward her eggs. Befide the example of the common fowl above alluded to, many others occur. If you deftroy the neft of a blackbird, a robin, or almoft any fmall bird, in the fpring, when she has laid her usual number of eggs, it is well known to every one, who has paid any attention to inquiries of this kind, in

how very fhort a space of time she will produce a fresh fet. Now, had the bird been suffered to have proceeded without interruption in her natural course, the eggs would have been hatched, and the young ones brought to a state capable of providing for themselves, before the would have been induced to make another neft, and excited to produce another fet of eggs from the ovarium. If the bird had been deftroyed at the time fhe was fitting on her first laying of eggs, diffection would have fhewn the ovarium containing a great number in an enlar ged ftate, and advancing in the ufual progreffive order. Hence it plainly ap pears, that birds can keep back or bring forward, under certain limitations, their eggs at any time during the feafon appointed for them to lay; but the cuckoo, not being fubject to the common interruptions, goes on laying from the time fhe begins, till the eve of her departure from this country: for although old cuc koos in general take their leave the first week in July, and I never could fee one after the 5th day of that month, yet I have known an inftance of an egg's being hatched in the neft of a hedge-fparrow fo late as the 15th. And a farther proof of their continuing to lay till the time of their leaving us may, I think, be fairly deduced from the appearances on diffection of the female cuckoo above mentioned, killed on the 3d of July.

Among the many peculiarities of the young cuckoo, there is one that fhews itself very early. Long before it leaves the neft, it frequently, when irritated, affumes the manner of a bird of prey, looks ferocious, throws itself back, and pecks at any thing prefented to it with great vehemence, often at the fame time making a chuckling noise like a young hawk. Sometimes, when disturbed in a fmaller degree, it makes a kind of hiffing noise accompanied with a heaving motion of the whole body. The growth of the young cuckoo is uncommonly rapid.

The chirp is plaintive, like that of che hedge-sparrow; but the found is not acquired from the fofter-parent, as it is the fame whether it be reared by the hedgefparrow, or any other bird. It never acquires the adult note during its stay in this country.

The ftomachs of young cuckoos contain a great variety of food. On diffecting one that was brought up by wag. tails, and fed by them at the time it was

shot,