The Zoologist/4th series, vol 5 (1901)/Issue 726/Observational Diary of the Habits of Great Crested Grebe and Peewit, Selous

by Edmund Selous

 

AN OBSERVATIONAL DIARY OF THE HABITS—
MOSTLY DOMESTIC—OF THE GREAT CRESTED
GREBE (PODICIPES CRISTATUS), AND OF THE
PEEWIT (VANELLUS VULGARIS), WITH SOME
GENERAL REMARKS

By Edmund Selous.

(Continued from p. 350.)

 

May 3rd, 1901.—I was here this morning from about 4.30 a.m., but an unfortunate circumstance obliged me to leave at 7; and on the following day I was unable to come, owing to being indisposed. Up to my leaving, no pairing and no peculiar antic or display between the two birds—as witnessed the previous morning—had taken place. Twice, however, the two had approached the nest, and each had lain along the water, as though inviting the other, in the way I have recorded in my notes of last year. On each occasion this was followed by an approach of the birds to the nest, but the impulse was not sufficient to cause either of them to ascend it, though this was evidently in their minds. This, together with all their actions in this respect which I have witnessed, makes me think that the actual pairing of these birds takes place, always, either on the nest itself, or on some structure of weeds, either naturally or artificially formed for the purpose, the lying along the water being only the suggestion preliminary to the subsequent ascent. Such, at least, has always been the case, and the manner in which the pairing is accomplished, the one bird standing entirely upright—like a Penguin—on the body of the other, would seem to necessitate some solid foundation. Nevertheless, the lying along the water may point to a past state of things, in which pairing took place in it, as it does now with Ducks.

During all the time I was here (from 4.40 to 6.45, to be precise) neither of the two birds carried any weeds to the nest, or at all busied themselves with it. Assuming the nest to be the ordinary one in which the eggs will be laid, then it has been built earlier than it was the previous year—at least than the one which I first saw. Also, it differs in hardly being raised above the surface of the water—no more, in fact, than a floating weed—so that it is undiscernible, unless when standing just over it, whilst the other was quite conspicuous.

May 5th.—At the water just after 7 a.m. (having had to walk), and find the two birds separated by some distance. The male is near me, but soon works back to the female, and, when they meet, they utter the curious, low, quacking kind of note. They are now floating idly on the water. Each time I see them together, or even apart, I am more struck with the superior size of the male. His body is larger, his neck thicker and held habitually higher, his crest finer and thicker, his whole appearance more striking. It would not be easy for me, now, to mistake one for the other through the glasses, even at a considerable distance, nor have I ever, in fact, had a real doubt except when I was a long way off. The two are now fishing, and very successfully, for they often bring a fish up and swallow it on the surface.

It is very funny to see not only the foot, but the whole leg of one of these Grebes lifted right into the air, and shaken backwards and forwards—waggled about. This has just happened with the hen.

At a little past eight the two have fronted each other in the water, and toyed in the usual manner. But nothing more has come of this, and it is now near 9.30. It is a cold ungenial morning.

At 10 I leave, nothing more having taken place, or seeming likely to take place, between the birds. Yesterday I was not able to come owing to headache.

May 9th.—I am at the water at 7.30 this morning, and find the Grebes swimming about together. Twice they front each other in the water, stretch up their necks, and toy a little with their beaks; and a third time they do this less definitely. But they do not go to the nest. At 8.10 I notice them diving somewhat excitedly, as it seems to me, one going down as soon as the other does, and sometimes—especially once—with a little splash. They also get over by the opposite shore, close in and together, and I am expecting a repetition of the curious actions I saw before, and which directly preceded the pairing on the nest. Nothing of the sort takes place, however, and in whatever way this diving may have begun, the birds are soon merely fishing. I wait till about 8.30, and then walk down to the nest, and once more carefully examine it. It is certainly a made structure, but, as certainly, altogether slight and insignificant, compared to those of last year. One might call it a degenerate nest, and it certainly suggests the idea that it has only been constructed—up to the present, at least—for the purpose for which it has alone been used.

May 11th.—Arrive at 7 a.m., and see the Grebes confronting, &c. Shortly afterwards they swim to the accustomed place, and the female—who leads the way—lies along upon the water amongst the growing weeds. The male goes up to her, appearing interested, but all at once he turns right round, so that the two are tail to tail, and lowers his own head, lying along in the same way, but not to such a complete extent. Both, then, resume the normal attitude, and, approaching each other, the male passes the female, and, pressing to the nest, ascends it, and lies along in the customary manner. The female, however, though her actions show that she is quite aware of the state of the case, does not respond, and the male, soon taking the water again, first dives and places a piece of weed on the nest, and the two then swim away together and float, dive and preen themselves, as usual. At 7.30 the male swims to the nest, and lies along on the water close to it. He is followed by the female, who, when she arrives at the patch of weeds, does the same; but there is nothing further, and, very shortly, the two swim off together. At 8.15 both again swim to the nest, and the male, who is much in advance, ascends and lies along it, as before. This, however, has the effect of making the female turn and swim out to some little way, as though coyly. The male comes off and follows her, when, turning, she eagerly swims to him; but when they join there is nothing particular between them. There have thus, this morning, been several visits paid to the nest with the idea of pairing, and two ascensions by the male. Now the morning is fine and warm, the lake once more a sun-bath, though misty. For the last week the weather has been cold and detestable. The birds' inclinations and activities seem to follow the weather. At 8.20 I have to leave, so cannot say if the actual pairing was accomplished or not.

May 13th.—At the water to-day at 11 a.m., and again at about 1.30 p.m. Each time the Grebes were floating idly about, and showed no disposition towards connubiality.

May 14th.—Arrive at about 7 a.m. The two birds are floating idly about together, and, before long, they front each other with reared necks, in the way often alluded to. Then, without táter-ing, each throws up the head several times into the air, at the same time opening and closing the long slender bill. This I have seen them do several times before, but hardly so pronouncedly. The bill, however, is so fine, and its lines, when thus opened, so soon lost, that this action makes less impression upon one than the gross gobble—as one may call it—of the Shag, and (no doubt) the Common Cormorant. It is a finer and more aristocratic affair altogether. It has a lady-like character—indeed, this can be said of the general appearance and deportment of both the birds. Bismarck, I think, has said, "In races, also, you have the male and the female." The remark was à propos of the Slav peoples, yet the Russian nationality, at any rate, if it shows—really or fancifully—some feminine traits, seems, at least, as strong, persistent, and inflexible as the German, or any other Teutonic one.

In about half an hour the two birds begin fishing, starting off diving with excitement and energy, and, as it seems to me, with a certain amount of consciousness between them. After a time they become separated, and, for a good while, one floats on the water (having finished fishing) quite alone. Now, however, the one is swimming down to it, and they soon rejoin. Both are now floating with their heads in the middle of their backs, looking like pork-pies on the water. As it is now half-past eight, and there is no sign of any nuptial activities, I leave.

My diary ends here. For several mornings after this, and then, on and off, till the end of the month, I continued to visit the lake, but the doings of the birds became less and less interesting, and it became, at last, evident to me that no eggs would be laid. Going again, on the 12th of June, I was unable to discover them on any part of the water, and came to the conclusion that they had abandoned it and the nest.

From the above observations, as well as those which I made last year, it may, I think, be concluded that the nest of the Great Crested Grebe is used, habitually, by the birds to pair on; so that, if it were used for no other purpose, and the eggs were laid elsewhere, it would not be a nest at all. It would, in fact, then be a "bower," or something very much resembling one—a thalamum, round and about which, in time, all the bird's coquetries might take place; whilst its subsequent gradual elaboration and ornamentation, in the case of species gifted with a higher aesthetic sense, offers no particular difficulty that I can see. Inasmuch, however, as the instinct of incubation would in all cases—we may assume—when the eggs had once been laid, overpower the primary sexual one, why should the two clash with each other, and, if they did not clash, why should not one and the same structure subserve, without inconvenience, the uses of both? First, it must be remembered that these Grebes paired on the nest, after one egg, at least, had been laid. Here, therefore, is a risk of the eggs being broken, and anything that diminished such risk would be an advantage to the species. But I have suggested another, and, as I think, a more powerful cause, by which the bower or thalamum may have become, in time, a distinct and separate structure from the true nest—as we see in the case of the Bower-birds. If I here repeat myself, somewhat, I hope I may be excused, for I wish to recall the speculations already indulged in, before proceeding to some further ones, which arise, naturally, out of them, whether supported or not by facts which I have observed, and will shortly record. Many birds, then, build more than one nest; and, if all of these nests were used as thalama for the performance of the nuptial rite, whilst only the last-made one received the eggs, then, gradually and quite naturally, two separate structures for two separate purposes might take the place of the one "contrived a double debt to pay." This would be but according to the principle of differentiation, or specialization ("specialization of parts," one might almost, by a metaphor, call it)^[1] which prevails throughout nature. Moreover, as the eggs would only be laid—after a full indulgence of the sexual passion—in the last nest, the incubating instinct might gradually restrain the birds—now somewhat sated—from pairing on that one; whilst the others, being used for that purpose only, would tend more and more to be built for it only, too. With regard to the multiplication of nests, we have the Wren as a familiar example of the habit, whilst my last year's observations on these same two Grebes record it in this species. Peewits are another instance, for they make a number of hollows, in all respects similar to the one in which the eggs are finally deposited, though, from their strange manner of doing this, another question arises, which I shall shortly bring forward. None of these birds are at all closely allied to the Bower-birds of Australia, but in the Thrush and the Blackbird we, at any rate, get a good deal nearer to them. With regard to the Blackbird, I have seen one clear instance of an apparently quite capricious abandonment of an almost finished nest in order to build another; nor is it in the least likely that I happened here—any more than in the case of the Grebes—to come upon a pair of very exceptional birds. It is the rarest thing, I think, speaking generally, to meet with a real exception. The appearance of it, in nine hundred and ninety-nine cases out of a thousand, marks but our ignorance. There remains the Thrush, and to this bird I paid some attention this spring, and was surprised at the number of nests which I found in different stages of construction, and which were not afterwards completed. That birds have, as a rule, any particular—or, at least, any clearly defined—object in building more than one nest, I do not myself believe; but, be that as it may, such a habit, joined to the one of pairing on the nest, appears to me to offer just that sort of foundation out of which such a state of affairs as we have with the Bower-birds might eventually arise.

But now another question arises. If a certain structure—the nest—is habitually made use of by any species of bird for pairing as well as for laying eggs in, which of these two uses are we to consider as the primary, and which the secondary one? In other words, has the bird built a thalamum which has become, in time, a nest, or a nest which has become a thalamum? This brings us to the origin of nest building, which need not, necessarily, have been the desire to shelter and conceal the eggs. It is possible that both that and the idea of doing so were developed after, and by reason of the nest itself, which, in its early stages, may have been due to other and widely different causes. Eggs and young must, of necessity, be preceded by sexual intercourse, and in the case of the Crested—probably of all the Grebes—it seems likely that such intercourse takes place on the nest alone. With the vast majority of birds, however, this is quite otherwise. Pairing on the nest, if it takes place at all (I have observed it in the case of the Rook, which again brings us nearer to the Bower-birds), does so probably as an exception, nor is it easy to see why this should ever have been otherwise. But (if I may be allowed to sketch my theory first, and give the facts on which I found it afterwards) let us assume two things, neither of which, perhaps, is highly improbable—viz.: first, that the primæval bird, or birds, made no nest; and, secondly, that the first eggs were laid on the ground. Supposing, then, that a male ground-laying bird that makes no nest indulges during the season of love, till shortly before the actual laying of the eggs, in all sorts of strange frenzied movements upon the ground, and that these movements tend to become localized and concentrated in some particular spot or spots in which—or one of which—the female, as sexually attracted thereto, ultimately lays her eggs, have we not here the nucleus, or, at any rate, the potentiality, of the future nest? And where—before the eggs were laid—would pairing have been so likely to have taken place as in one of these very spots—these vortexes, so to speak, of the sexual whirlwind? Can we not imagine a custom, gradually shaping itself out of this, of laying the eggs in some place where pairing was habitually indulged in, so that if such place afterwards became, in any true sense, a nest, we would here have habitual pairing upon it?

Having got so far, let us now suppose that one chief form of these frenzied movements alluded to, is a rolling upon or a buzzing or spinning over the ground, by which means the bird so acting produces a larger or smaller depression in it. If the eggs are laid in such a depression, they are now laid in a nest, but such nest will not have been produced with any idea of concealing the eggs or sheltering the young. It will be due to nervous and non-purposive movements springing out of the violence of sexual passion, and, moreover, it will often have been made mostly, if not altogether, by the male bird. Now, as everyone knows, numbers of ground-laying birds deposit their eggs in a depression made either wholly or partly by themselves; whilst others, such as the Great Plover and the Nightjar, do not—that, at least, is the common view—make any kind of artificial hollow, though they may, in some cases, take advantage of a natural one. We will suppose that in the former case, as well as in some instances of the latter, we see the primitive nest or pairing-place, produced or located in the manner indicated. Now, however, comes a farther stage which, it might well be thought, could have originated only in deliberate and purposive action on the part of the bird. I allude to the lining of grass, moss, sticks, or even stones or fragments of shells, with which many birds who lay their eggs in a hollow made by them in the ground, further improve it. That this process (or, at any rate, the later stages of it) has now, with most birds, become a deliberate one, I do not doubt. But, as every evolutionist will admit, it is the beginnings of anything which best explain and are most fraught with significance. Is it possible that even the actual building of the nest may have had a nervous—a frenzied—origin? Lions and other fierce carnivorous animals will, when wounded, bite at sticks, or anything else lying within their reach. That a bird, as accustomed to peck as is a Dog or Lion to bite, should, whilst in a state of the most intense nervous excitement, do the same, does not appear to me to be more strange, or, indeed, in any way peculiar; and that such a trick would be inherited, and, if beneficial, increased and modified, who (having evolution in his soul) can doubt? If a bird, whilst ecstatically rolling on the ground, were to pick up and throw aside either small sticks, or any other loose-lying and easily-seized objects—such as bits of grass or fibrous roots—I can see no reason why it should not, by stretching out its neck to such as lay only just within reach, and dropping them again when in an easier attitude, make a sort of collection of them close about it.^[2] Then, if the eggs were laid where the bird had rolled, they would be laid in the midst of such a collection, which would, of course, be increased, were the female bird to act in a similar way, and in the same place. Nor is this last so unlikely, for in many species both sexes indulge in the same odd postures and contortions during the breeding season.

All the above suppositions have been suggested to me by what I have actually seen birds do whilst under the influence of strong sexual excitement, and, though I am ready to admit that the foundation of fact may have been slight in comparison with the superstructure of theory raised upon it, yet there can be no harm in a provisional hypothesis; and, besides, what is the use of staring at facts with eyes that have "no speculation" in them? For myself, I shall always strive to see the causes of things with the things; nor do I know of anything worse that can happen to one by this method than to have it pronounced on all hands that one's theories are "less happy" than one's records of facts, a dictum which, till argument is met by argument, one may take to mean something like this—"We are equal to a fact or two, but theories make our heads spin round."

(To be continued.)

 

---

1. Comparing the different nests to multiplied organs of a living body, as e.g. the limbs of some crustaceans, which, being at first used both for walking and other purposes, have now become specialized into jaws, claws, and more effective legs.
2. Since writing this paper I have read that of Mr. Cronwright Schreiner on the Ostrich in 'The Zoologist' for 1897, and as a part of it seems to me to support my theory, I quote it here, though it should be read, also, with reference to some of those actions upon which I found it, and which I am about to recount:—
   "The nest.—...."made by the pair together. The cock goes down on to his breast, scraping or kicking the sand out backwards with his feet, &e. The hen stands by, often fluttering and clicking her wings, and helps by picking up the sand with her beak, and dropping it irregularly near the edge of the growing depression.
   "The little embankment round the nest.... The sitting bird, while on the nest, sometimes pecks the sand up with its beak nearly as far from the nest as it can reach, and drops it around the body. A little embankment is thus gradually formed.... The formation.... is aided by a peculiar habit of the birds. When the bird on the nest is much excited (as by the approach of other birds or people) it snaps up the sand spasmodically without rising from the nest, and without lifting its head more than a few inches from the ground. The bank is raised by such sand as falls inward. The original nest is merely a shallow depression."
   Remarks follow on the use of the bank, which has become a part—and an important part—of the nest. We, however, are concerned with the origin both of it and the depression. It seems clear, from the account, that the former is sometimes made, or added to, when there can hardly be an intention of making it: whilst, to make the latter, the cock assumes the attitude of sexual frenzy (described in the same paper), which is one, as it seems to me, hardly necessary for mere scratching alone. Had the latter, however, grown out of the former, we can well understand the characteristic posture being continued. The italics are my own.