Our Summer Migrants / An Account of the Migratory Birds Which Pass the Summer in the British Islands.

THE CUCKOO. ( Cuculus canorus. )

From numerous observations made by competent naturalists in different localities, it appears that the usual time of arrival of the Cuckoo in this country is between the 20th and 27th of April, and the average date of its appearance may be said to be the 23rd of that month, St. George’s Day. In no instance, so far as I am aware, has the bird been heard or seen before the 6th of April. On that date in 1872 it was observed at Torquay, but this was considered by my informant an unusually early date at which to meet with it.

Between April and the end of August, it may be found generally distributed throughout the British Islands, even as far north as Orkney and Shetland. It is also a well-known visitor to the Outer Hebrides. On the European continent it occurs throughout Scandinavia and Russia, and is found in all the countries southward to the Mediterranean, which it crosses in the autumn for the purpose of wintering in North Africa. Eastward it extends through Turkey, Asia Minor, and Persia, to India, and according to Horsfield and Temminck, visits even Java and Japan.[97]

The Cuckoo does not pair, but is polygamous. It is not unusual, soon after their arrival, to see a couple of male birds chasing a hen. The first eggs are seldom laid before the middle of May, or not until the birds have been here three weeks or a month. The egg, which is about equal in size to that of the Skylark, is very small, considering the bulk of the bird which lays it. It is white, closely freckled over with grey, or sometimes reddish brown, and generally has a few darker specks at the larger end. Instead of building a nest for itself, the Cuckoo deposits its eggs singly, and at intervals of a few days, in the nests of a variety of other birds, and leaves them to be hatched out, and the young reared, by the foster parents.

The nests in which the Cuckoo’s eggs are most frequently deposited are those of the Hedge Sparrow, Meadow Pipit, Pied Wagtail, and Reed Warbler, but according to Dr. Thienemann, a great authority on the subject of European birds’ eggs, they have also been found in the nests of the following very different species:—

Garden Warbler.

Blackcap.

Whitethroat.

Lesser Whitethroat.

Redstart.

Black Redstart.

Robin.

Reed Warbler.

Sedge Warbler.

Marsh Warbler.

Grasshopper Warbler.

Willow Wren.

Hedge Sparrow.

Common Wren.

Whinchat.

White Wagtail.

Grey-headed Wagtail.

Tawny Pipit.

Meadow Pipit.

Skylark.

Yellowhammer.

To this list Dr. Baldamus, from other sources, has added the following:[98]—

Red-backed Shrike.

Barred Warbler.

Nightingale.

Icterine Warbler.

Chiff-chaff.

Great Reed Warbler.

Sedge Warbler.

Fire-crested Wren.

Tree Pipit.

Crested Lark.

Wood Lark.

Common Bunting.

Black-headed Bunting.

Greenfinch.

Linnet.

Russet Wheatear.

And lastly, in a foot-note to Mr. Dawson Rowley’s article on the Cuckoo,[99] in which the above lists were quoted, Professor Newton has pointed out the authority which exists for including the following, at least occasionally, amongst the foster parents of the young Cuckoo:—

House Sparrow.

Blue-throated Warbler.

Rock Pipit.

Chaffinch.

Blackbird.

Grasshopper Warbler.[100]

Great Titmouse.

Red-throated Pipit.

Mealy Redpoll.

Bullfinch.

Jay.

Song Thrush.

Magpie.

Turtle Dove.

Wood Pigeon.

He confirms, moreover, Mr. Rowley’s remark that the Cuckoo’s egg is occasionally found in the nest of the Brambling (Fringilla montifringilla).

I have still to name four species which are not included in any of the above lists, viz., the Spotted Flycatcher, Yellow Wagtail, Grey Wagtail, and Wheatear. They were noticed by me some years ago in the first work I ever published.[101] In the case of the Wheatear, a nest of that bird containing three eggs of the Wheatear and one of the Cuckoo was placed under a clod, and in such a position as strongly to favour the opinion of some naturalists that the Cuckoo first lays her eggs and then deposits them with her bill in the nest.

Considering the amount of attention which has been bestowed upon the Cuckoo by naturalists in every age down to the present, one would suppose that every fact in connection with its life-history was now pretty generally known. Such, however, is not the case. There are still certain points which require investigation, and which, owing chiefly to the vagrant habits of the bird, are not easily determined.

How can it be ascertained with certainty, for example, whether the same hen Cuckoo always lays eggs of the same colour, or whether (admitting this to be the case) she invariably lays in the nest of the same species—that is, in the nest of that species whose eggs most nearly approximate in colour to her own?

And yet we must be satisfied on these points if we are to accept the ingenious theory of Dr. Baldamus. If we understand the learned German rightly, he states that, with a view to insure the preservation of species which would otherwise be exposed to danger, Nature has endowed every hen Cuckoo with the faculty of laying eggs similar in colour to those of the species in whose nest she lays, in order that they may be less easily detected by the foster parents, and that she only makes use of the nest of some other species (i.e. of one whose eggs do not resemble her own) when, at the time she is ready to lay, a nest of the former description is not at hand. This statement, which concludes a long and interesting article on the subject in the German ornithological journal “Naumannia,” for 1853, has deservedly attracted much attention. English readers were presented with an epitome of this article by Mr. Dawson Rowley in the “Ibis” for 1865, and the Rev. A. C. Smith, after bringing it to the notice of the Wiltshire ArchÆological Society in the same year, published a literal translation of it in the “Zoologist” for 1868. More recently, an article on the subject, by Professor Newton, appeared in “Nature” and elicited various critical remarks from Mr. H. E. Dresser, Mr. Layard, and other ornithologists which deserve perusal.[102]

To enter fully upon the details of this interesting subject would require more space than can here be accorded; one can only glance therefore at the general opinions which have been expressed in connection with it.

If the theory of Dr. Baldamus be correct, is it possible to give a reasonable and satisfactory explanation of it? This question has been answered by Professor Newton in the article to which we have just referred. He says:—“Without attributing any wonderful sagacity to the Cuckoo, it does seem likely that the bird which once successfully deposited her eggs in a Reed Wren’s or a Titlark’s nest, should again seek for another Reed Wren’s, or a Titlark’s nest (as the case may be) when she had an egg to dispose of, and that she should continue her practice from one season to another. We know that year after year the same migratory bird will return to the same locality, and build its nest in almost the same spot. Though the Cuckoo be somewhat of a vagrant, there is no improbability of her being subject to thus much regularity of habit, and indeed such has been asserted as an observed fact. If, then, this be so, there is every probability of her offspring inheriting the same habit, and the daughter of a Cuckoo which always placed her egg in a Reed Wren’s or a Titlark’s nest doing the like.” In other words, the habit of depositing an egg in the nest of a particular species of bird is likely to become hereditary.

This would be an excellent argument in support of the theory, were it not for one expression, upon which the whole value of the argument seems to me to depend. What is meant by the expression “once successfully deposited”? Does the Cuckoo ever revisit a nest in which she has placed an egg, and satisfy herself that her offspring is hatched and cared for? If not (and I believe such an event is not usual, if indeed it has ever been known to occur), then nothing has been gained by the selection of a Reed Wren’s or Titlark’s nest (as the case may be), and the Cuckoo can have no reason for continuing the practice of using the same kind of nest from one season to another.

While admitting therefore the tendency which certain habits have to become hereditary in certain animals, I feel compelled to reject the application of this principle in the case of the Cuckoo, on the ground that it can only hold good where the habit results in an advantage to the species, and in the present instance we have no proof either that there is an advantage, or, if there is, that the Cuckoo is sensible of it.

Touching the question of similarity between eggs laid by the same bird, Professor Newton says:—“I am in a position to maintain positively that there is a family likeness between the eggs laid by the same bird” (not a Cuckoo) “even at an interval of many years,” and he instances cases of certain Golden Eagles which came under his own observation. But do we not as frequently meet with instances in which eggs laid by the same bird are totally different in appearance? Take the case of a bird which lays four or five eggs in its own nest before it commences to sit upon them—for example, the Sparrow-Hawk, Blackbird, Missel-Thrush, Carrion Crow, Stone Curlew, or Black-headed Gull. Who has not found nests of any or all of these in which one egg, and sometimes more, differed entirely from the rest? And yet in each instance these were laid, as we may presume, not only by the same hen, but by the same hen under the same conditions, which can be seldom, if ever, the case with a Cuckoo.

Looking to the many instances in which eggs laid by the same bird, in the same nest, and under the same circumstances, vary inter se, it is not reasonable to suppose that eggs of the same Cuckoo deposited in different nests, under different circumstances, and, presumably, different conditions of the ovary, would resemble each other. On the contrary, there is reason to expect they would be dissimilar. Further, I can confirm the statement of Mr. Dawson Rowley, who says:[103] “I have found two types of Cuckoo’s eggs, laid, as I am nearly sure, by the same bird.”

It is undeniable that strong impressions upon the sense of sight, affecting the parent during conception or an early stage of pregnancy, may and do influence the formation of the embryo, and it has consequently been asserted that the sight of the eggs lying in the nest has such an influence on the hen Cuckoo, that her egg, which is ready to be laid, assumes the colour and markings of those before her. This is not, however, supported by facts, for the egg of a Cuckoo is frequently found with eggs which do not in the least resemble it (e.g. those of the Hedge-Sparrow); or with eggs which, from the nature of the nest, could not have been seen by the Cuckoo (as in the case of the Redstart, Wren, or Willow Wren); or deposited in a nest before a single egg had been laid therein by the rightful owner. Again, two Cuckoo’s eggs of a different colour have been found in the same nest. If both were laid by one bird, we have a proof that the same Cuckoo does not always lay eggs of the same colour; if laid by different birds, then the Cuckoo is not so impressionable as has been supposed.

What really takes place, I believe, is this:—The Cuckoo lays her egg upon the ground; the colour of the egg is variable according to the condition of the ovary, which depends upon the age of the bird, the nature of its food, and state of health at the time of oviposition. With her egg in her bill, the bird then seeks a nest wherein to place it. I am not unwilling to accept the suggestion that, being cognizant of colour, she prefers a nest which contains eggs similar to her own, in order that the latter may be less easily discovered by the foster parents. At the same time the egg in question is so frequently found amongst others which differ totally from it in colour, that I cannot think the Cuckoo is so particular in her choice as Dr. Baldamus would have us believe.

The manner in which “the cuckowe’s bird useth the sparrow,” “oppressing his nest,” living upon him, and finally turning him adrift, has furnished a theme for poets and prose writers in all ages, and has awakened in no small degree the speculative powers of naturalists.

The story is as old as the hills, and it would probably be difficult, if not impossible, to trace it to its origin. It was known to the ancients that the Cuckoo leaves its eggs to be hatched by other birds, but they mingled fact with fable, believing, or at all events asserting, that the young Cuckoo devoured not only its foster brothers and sisters, but ultimately its foster parents. Hence the expression which Shakespeare put into the mouth of the Earl of Worcester to the effect that the youngster

“Grew by our feeding to so great a bulk

That even our love durst not come near his sight

For fear of swallowing.”—Henry IV. act v. sc. 1.

But though so time-worn is the tale as to be very generally believed, it is singular how few writers have attempted to show a foundation for it from their own observations. So scattered, indeed, is the evidence on the subject, that many naturalists of the present day still hesitate to believe the story, pronouncing the alleged feat of strength on the part of the young Cuckoo to be “a physical impossibility.”

Although my present purpose is to direct attention to the latest observations upon this vexed question which have come to us with authority, it will not be superfluous to glance very briefly at what had already been advanced in support of the statement referred to.

Dr. Jenner says positively (“Phil. Trans.,” vol. lxxviii. p. 225):—“I discovered the young Cuckoo, though so newly hatched, in the act of turning out the young Hedge-Sparrow. The little animal, with the assistance of its rump and wings, contrived to get the bird upon its back, and making a lodgement for its burden by elevating its elbows, clambered backwards with it up the side of the nest till it reached the top, where, resting for a moment, it threw off its load with a jerk, and quite disengaged it from the nest. It remained in the situation for 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 nest again.”

Montagu, in the Introduction to his “Ornithological Dictionary,” states that he took home a young Cuckoo five or six days old, when, to use his own words: “I frequently saw it throw out a young Swallow (which was put in for the purpose of experiment) for four or five days after. This singular action was performed by insinuating itself under the Swallow, and with its rump forcing it out of the nest with a sort of jerk. Sometimes, indeed, it failed after much struggle, by reason of the strength of the Swallow, which was nearly full feathered; but, after a small respite from the seeming fatigue, it renewed its efforts, and seemed continually restless till it succeeded.”

Mr. Blackwall, who published some observations on this point in the fourth volume of the “Manchester Memoirs” (second series), says that a nestling Cuckoo, while in his possession, turned both young birds and eggs out of its nest, in which he had placed them for the purpose. He further observed “that this bird, though so young, threw itself backwards with considerable force when anything touched it unexpectedly,” an observation subsequently confirmed by Mr. Durham Weir in a letter to Macgillivray.[104]

Mr. Weir says a young Cuckoo was hatched with three young Titlarks on the 6th June. “On the afternoon of the 10th two of the Titlarks were found lying dead at the bottom of the ditch; the other one had disappeared.” Subsequently this Cuckoo was removed, and placed in another Titlark’s nest, nearer home, for more convenient observation. On the following day Mr. Weir found it covered by the old Titlark “with outstretched wings from a very heavy shower of rain * * * while her own young ones had in the meantime been expelled by the Cuckoo, and were lying lifeless within two inches of her nest.” Another instance is given wherein two Cuckoos were hatched in a Titlark’s nest. “On the third or fourth day after this the young Titlarks were found lying dead on the ground, and the Cuckoos were in possession of the nest.” Ultimately one of the latter, the weaker of the two, disappeared.

A German naturalist, Adolf MÜller, of Gladenbach, writing in a German periodical, “Der Zoologische Garten,” in October, 1868, has given a curious account of the conduct of two young Cuckoos, which were hatched in the nest of a Robin. A translation of this account was published in “The Field” of Nov. 21, 1868, and it will be unnecessary therefore to give more than the merest outline of the facts detailed in it.

Two young Cuckoos, five or six days old, were found in a Robin’s nest, four Robin’s eggs lying on the heath before the nest. The two birds were extremely restless, striving to push each other out of the nest, the smaller one always the more active. Herr MÜller placed the smaller on the back of the larger one, which immediately began to heave it upwards, and, thrusting its claws into the moss and texture of the nest, actually succeeded in pushing it to the edge of the nest and about four inches further amongst the heath stems. After every contest which was observed both birds contrived to creep back again into the nest. Ultimately the larger one was found lying dead outside the nest, while the Robin was sitting on the smaller bird and the eggs, which had been replaced.

The latest contribution on the subject is that of Mr. Gould, who in his splendid folio work on “The Birds of Great Britain,” expressed himself a disbeliever in the popular story. He has since found reason to change his opinion, for in his recently published octavo “Introduction” to that work he says: “I now find that the opinion ventured in my account of this species as to the impossibility of the young Cuckoo ejecting the young of its foster parents at the early age of three or four days is erroneous; for a lady of undoubted veracity and considerable ability as an observer of nature, and as an artist, has actually seen the act performed [he seems to overlook the circumstance that others had previously seen it], and has illustrated her statement of the fact by a sketch taken at the time, a tracing of which has been kindly sent to me.”

This tracing he has reproduced as an engraving in the “Introduction” referred to, and as he has been good enough to allow me the use of the wood block to illustrate the present remarks, the reader may consider himself in possession of a fac-simile sketch from nature.

The following is the account given by Mrs. Blackburn (the lady referred to) of the circumstance as it came under her observation:[105]—

“The nest which we watched last June, after finding the Cuckoo’s egg in it, was that of the Common Meadow Pipit (Titlark, or Moss-Cheeper), and had two Pipit’s eggs, besides that of the Cuckoo.

“It was below a heather bush, on the declivity of a low abrupt bank, on a Highland hill-side, in Moidart. At one visit the Pipits were found to be hatched, but not the Cuckoo.

Cuckoo in nest

“At the next visit, which was after an interval of forty-eight hours, we found the young Cuckoo alone in the nest, and both the young Pipits lying down the bank, about ten inches from the margin of the nest, but quite lively after being warmed in the hand. They were replaced in the nest beside the Cuckoo, which struggled about till it got its back under one of them, when it climbed backwards directly up the open side of the nest, and hitched the Pipit from its back on to the edge. It then stood quite upright on its legs, which were straddled wide apart, with the claws firmly fixed half-way down the inside of the nest among the interlacing fibres of which the nest was woven; and, stretching its wings apart and backwards, it elbowed the Pipit fairly over the margin so far that its struggles took it down the bank instead of back into the nest.

“After this the Cuckoo stood a minute or two, feeling back with its wings, as if to make sure that the Pipit was fairly overboard, and then subsided into the bottom of the nest.

“As it was getting late, and the Cuckoo did not immediately set to work on the other nestling, I replaced the ejected one and went home. On returning next day both nestlings were found dead and cold, out of the nest. I replaced one of them, but the Cuckoo made no effort to get under and eject it, but settled itself contentedly on the top of it. All this I find accords accurately with Jenner’s description of what he saw. But what struck me most was this: The Cuckoo was perfectly naked, without a vestige of a feather, or even a hint of future feathers; its eyes were not yet opened, and its neck seemed too weak to support the weight of its head. The Pipits had well-developed quills on the wings and back, and had bright eyes, partially open; yet they seemed quite helpless under the manipulations of the Cuckoo, which looked a much less developed creature. The Cuckoo’s legs, however, seemed very muscular; and it appeared to feel about with its wings, which were absolutely featherless, as with hands, the ‘spurious wing’ (unusually large in proportion), looking like a spread-out thumb. The most singular thing of all was the direct purpose with which the blind little monster made for the open side of the nest, the only part where it could throw its burthen down the bank.”

Notwithstanding the objections put forward by sceptics, it is impossible, after reading the evidence of the above-named independent observers, to doubt that the young Cuckoo is capable of doing all that has been attributed to it in the way of ejectment. But it is still very desirable that some competent anatomist should examine and report upon the arrangement and development of the nerves and muscles, which must differ very considerably from those which are to be found at the same age in the young of other insessorial birds.

WRYNECK

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