Chapter 5

"But why do not cuckoos make nests and sit on their eggs like other birds?" said Jack. Such a question is more easily asked than answered; nevertheless I hope you will always try to discover reasons for things. "It is now," writes a celebrated naturalist, "commonly admitted that the more immediate and final cause of the cuckoo's instinct is, that she lays her eggs, not daily, but at intervals of two or three days; so that if she were to make her own nest and sit on her own eggs, those first laid would have to be left for some time unincubated, or there would be eggs and young birds of different ages in the same nest. If this were the case the process of laying and hatching might be inconveniently long, more especially as she has to migrate at a very early period, and the first hatched young would probably have to be fed by the male alone." The cuckoos come to this country about the middle of April; the male birds arrive before the females. Whether this arrangement is ungallant conduct on the part of the gentlemen birds, who prefer to come alone, or whether, just when the gentleman cuckoo is ready and almost impatient for a start, her ladyship has all at once discovered some important matter that ought to be finished before leaving the country, some adjustment of her dress, some tiresome feather that will ruffle itself up in spite of every effort to keep it smooth, I know not, but the fact remains, that my Lord and Lady Cuckoo do not travel together. Let us suppose that both sexes have arrived in this country, we will say about the 23rd of April. It is natural they want a little time to look about them; at any rate, no egg is ready for being sat upon till some weeks after the arrival of the birds, say the 15th of May. The eggs require fourteen days' setting before they are hatched; this brings the date to the 29th of May. The young ones will require three weeks in the nest and constant feeding all the time; we now arrive at about the 20th of June, when the young ones would be ready to leave the nest. But they want five weeks' more feeding by the parents, after they leave the nest, before they are able to provide for themselves; this would bring the date to about the 25th of July, when there is hardly a parent bird in the country; they have left for other parts of the world. "Oh! but, papa," said Willy, "you said in the lines you told us to remember--

In July, He prepares to fly. Come August, Go he must.

And now you say the cuckoos leave before the end of July. I think you must have made a mistake somehow." I am glad that you have found out the error, if it is one. Old rhymes are not always to be trusted; but I suspect that the couplet "Come August, go he must," means to imply that the cuckoo does never really stay so late with us. I must not, however, forget to tell you that it is the old parent birds that leave us early; young birds remain till September, and even October, but they have not by that time acquired the cuckoo note. If you ask why cannot the old cuckoos stay with us a little longer, and then all go away together as a family party, young and old, in September, instead of being in such a hurry, I have only to say that it is the fashion amongst cuckoos, and of course cuckoos, like certain other animals, must be in the fashion. This is Dr. Jenner's explanation of the peculiar habits of the cuckoo in respect of its eggs. I am not prepared to say whether or not it is sufficient to explain them. The cuckoo's egg is very small when compared with the size of the bird; it is of a pale grey tinged with red.

"But how does the cuckoo's egg get into some of the nests?" asked Willy; "for some of the nests in which the cuckoo's egg is found are too small to allow the cuckoo herself to enter to lay her egg." You are quite right; I believe it has been proved that the cuckoo lays her egg on the ground, and carries it in her bill into other birds' nests.

"Oh! papa," said Jack, "what is this curious plant that grows so abundantly on the grass here? I know it well by sight, but do not know its name." It is a spike of horse-tail; see how the stem is marked with lines, and how curiously jointed it is, and quite hollow except where the joints occur. The fruit is borne at the top of the plant (_a_); see, as I shake it, what a quantity of dust comes from it; this dust is the fruit, or spores as they are called; each spore is of an oval form, with four elastic threads. If I were to put some of this dust on a glass slide, and look at it under the microscope, I should see a curious sight. The four threads would be spread out, but if I were to breathe on the glass, these threads would coil themselves round the oval body; but as soon as the effect of the moisture had passed away, the threads would shoot out again in the same position as they were at first, causing the spore to leap as if it were alive. The stems are of two kinds, fertile and unfertile; the one you have in your hands is a fertile spike, and appears only in the spring; the unfertile ones have no dust-like fruit, and have numerous jointed branches growing in rows, or whorls as they are termed, round them; they remain throughout the summer, and in some places form quite a thick cover. Feel how rough the stem is; this is due to the presence of a quantity of silex or flint in it; on this account some of the species are used for polishing purposes. One kind, under the name of "Dutch rushes," is imported from Holland, being used for polishing mahogany, ivory, metal, &c. The horse-tails for the most part grow in moist ground, in ditches and on the borders of lakes; some, however, are common in corn fields and on the roadside. In this country they do not attain a height of more than a few feet, but in tropical countries one or two species grow to the height of sixteen feet or more.

Now for a dip with the bottle in this pond. I will try and catch a few Hydræ. Strange animals, indeed, they are, and strange is their history; but let us catch a few first. Nothing yet in my bottle like a hydra. Ah! now we have one or two. You see a small creature sticking to the stem of a bit of duckweed; around its mouth are five or six little projections. At present they are contracted; but the hydra is able to lengthen them out, when they appear as long, thin lines, which are used as the creature's fishing-lines; it is not much larger than a pin's head at present, but it can stretch its body out as it does its lines. I will take a handful of duckweed, and put it, dripping wet, into this bag, and when we get home we will place the whole in a glass vessel full of water. In the course of half an hour or so, we shall, no doubt, see several hydræ, probably of different species, in various attitudes--some hanging loosely down, others erecting themselves in graceful curves and throwing out their arms or tentacles many times longer than their bodies; others shooting up their arms right above their heads; others contracted, looking like miniature dabs of jelly; others attached head and tail to the side of the glass; others floating on the surface of the water, their tail-ends sticking out and serving to keep them from sinking; some of a beautiful grass-green colour, others light brown or flesh colour, others almost white, others red. These creatures may be cut into several parts, yet each part will grow again into a perfect animal; young ones bud out of the sides of the parents. Some have said that they can be turned inside out, and find no inconvenience whatever from the operation. "But how," asked Willy, "could anybody manage to turn so small a thing as a hydra inside out?" It does seem an impossible task, I confess, and a man must have much skill and patience to enable him to accomplish it. However, I will give you the description of an attempt made many years ago by a celebrated naturalist of Geneva, named Trembley, who made the hydræ or fresh-water polypes a study for many years. This is what Trembley says:--"I begin by giving a worm to the polype on which I wish to make an experiment, and when it is swallowed I begin operations. It is well not to wait till the worm is much digested. I put the polype, whose stomach is well filled, in a little water in the hollow of my left hand; I then press it with a small forceps nearer to the tail end than to the head. In this way I push the swallowed worm against the mouth of the polype, which is thus forced to open, and by again slightly pressing the polype with my forceps I cause the worm partly to come out from its mouth, and thus draw out with it an equal part of the end of its stomach. The worm, coming out of the mouth of the polype, forces it to enlarge itself considerably, especially if it comes out doubled up. When the polype is in this state, I take it gently out of the water, without disturbing anything, and place it on the edge of my hand, which is simply moistened, so that it may not adhere too closely. I oblige it to contract more and more, and this also enlarges the stomach and mouth. The worm then is partly coming out of the mouth, and, keeping it open, I then take in my right hand a hog's bristle, rather thick and without a point, and I hold it as one holds a lancet for bleeding. I bring its thickest end to the hind end of the polype and push it, making it enter into its stomach, which is the more easily done as in that part it is empty and much enlarged. I push on the end of the hog's bristle, which continues to invest the polype. When it reaches the worm, which holds the mouth open, it either pushes the worm or passes by its side, and at last comes out by the mouth, the polype being thus completely turned inside out."

Very strange, indeed, to think that animals with the wrong side outermost should continue to eat, grow, and multiply, as Trembley assures us his specimens did, though, perhaps, we shall not wonder that they often tried to turn themselves back to their original condition, and with success, unless Trembley took steps to prevent them. There are other strange things recorded of the fresh-water polypes, as that different individuals can be grafted together without the slightest inconvenience to any of the parties, the joint-stock company of course being limited.

The hydræ live on small worms, larvæ of gnats, water-fleas, and other minute creatures; they catch them with their tentacles or fishing-lines, and draw them to the mouth. It is maintained by many observers, with good reason, that these arms have the power of paralysing, in an instant, the worms they wrap themselves round. There are at least three well-marked species of hydræ to be met with in the ponds and ditches of this country. There is the green hydra, the light flesh-coloured or common hydra, and the long-armed hydra, the most interesting of all. See, there is the water-primrose, now in flower, with its delicate pink corolla and bright orange centre. Let us gather a few plants, and then return home.

FOOTNOTES:

[Footnote B: 'Marvels of Pond Life,' by H. J. Slack, p. 92.]

WALK V.

MAY.

To-day we will go to Shawbury and try our luck with the trout. If the fish will not rise there will be plenty to observe, and I have no doubt we shall enjoy the day thoroughly; the wind is in the south-west and the day is cloudy; the May-fly is well out, and I think we have every chance of good sport. Let us look out our fishing-tackle and drive off at once to the river. How delightful it is to stroll by the river side and hear the rippling of the water; delightful, too, is the sensation of feeling at the end of your line the tugs and jumps of a good lively trout. I cannot resist quoting some lines from 'The Angler's Song,' which I think you will say are very pretty:

Merry in the greenwood is the note of horn and hound, And dull must be the heart of him that leaps not to their sound; Merry from the stubble whirrs the partridge on her wing, And blithely doth the hare from her shady cover spring; But merrier than horn or hound, or stubble's rapid pride, Is the sport that we court by the gentle river side.

Our art can tell the insect tribe that every month doth bring, And with a curious wile we know to mock its gauzy wing; We know what breeze will bid the trout through the curling waters leap, And we can surely win him from shallow or from deep; For every cunning fish can we a cunning bait provide, In the sport that we court by the gentle river side.

Where may we find the music like the music of the stream? What diamond like the glances of its ever-changing gleam? What couch so soft as mossy banks, where through the noontide hours Our dreamy heads are pillowed on a hundred simple flowers? While through the crystal stream beneath we mark the fishes glide, To the sport that we court by the gentle river side?

For as the lark with upland voice the early sun doth greet, And the nightingale from shadowy boughs her vesper hymn repeat; For as the pattering shower on the meadow doth descend, And far as the flitting clouds with the sudden sunbeams blend; All beauty, joy and harmony, from morn to eventide, Bless the sport that we court by the gentle river side.

Well, here we are once more at the charming little village of Shawbury. How often, both as a boy and a man, have I wandered by the banks of the river Roden. What changes have taken place since my early rambles! Long familiar forms, companions in my fishing expeditions, have vanished; the mind fondly cherishes their memory, and recalls past hours of cheerful intercourse. We will put up the horse and carriage at the Elephant and Castle Inn and stroll away to the river.

Ah! here is a capital place. Now, Master Willy, there is no tree to interfere with your throw, so cast in just near that spot, quietly, carefully, anxiously; if there is a fish there he cannot resist your green drake. I recommend him the artificial before the fat natural fly. As Christopher North says--"Devouring ephemerals! Can you not suffer the poor insects to sport out their day? They must be insipid eating--but here are some savoury exceedingly ... they carry _sauce piquante_ in their tails. Do try the taste of this bobber--but any of the three you please." There, hold fast, Willy, for that's a good one. Bring him up carefully to the side; hold your rod erect; play him a little, for he is full of vigour. There! well done; I have got him in the landing net. Is not he a beauty? A pound weight, I'll be bound; and what condition! His flesh will be almost as pink as that of a salmon. Further down stream I managed to take a fish in very different condition; I took him where the river was rather muddy, and flowed very slowly. Just look at him, with a body lean and dark coloured, and an enormous head for so slender a body. "Oh! but, papa," said Willy, "what are these curious creatures crawling over him? Do look." Ah! I know them well; anglers call them trout lice. I will scrape off a specimen, and put him in the bottle. Now look at him. The body is nearly round, and almost transparent; colour rather green; it has four pairs of swimming feet, each pair beset with a fringe of hairs; a pair of foot-jaws; a small half-cleft tail; and a pair of fleshy circular suckers just in front of the foot-jaws, by means of which the little creature is able to attach itself, as a parasite, upon various fish. It is a graceful little creature, and, as you see, can swim with great activity in the water; now it swims in a straight line, now it suddenly turns quickly round and turns over and over. It is known to naturalists under the name of _Argulus foliaceus_; I do not think it has any English name. It is found on many kinds of fish, and generally in greater abundance upon individuals that are in an unhealthy state; though these parasites often attach themselves to fish in good condition. The mouth is furnished with a long, sharp sucking-tube, by means of which the animal can pierce the skin of the fish it lives upon, and suck up the juices. We will take a few home, and I will show you the different parts of the creature under the microscope.

Let us now sit down and rest for an hour, and eat our lunch; the fish do not rise as freely as they did; perhaps later on they will be in the humour again. But what do I see sticking to the sides of that rail across the river; I must go and see. Well, really this is an interesting thing. An immense mass of flies, a few alive, but the greater number quite dead; and, look! a quantity of white eggs underneath them. Let us examine a fly; it is of a brown or tawny colour, and has rather long, diverging, colourless wings, marked with irregular brown spots. Why, there must be thousands of dead flies covering these eggs. What an odd idea! Presently up comes Mr. Collins from the farm near the bank of the stream. "Oh, sir, I know those flies quite well; they are oak-flies (_Leptis scolopacea_)." Certainly not, I replied, though they do somewhat resemble them in colour and appearance; but the farmer stoutly asserted he was right, and I did not think it worth while discussing the matter further with him. Mr. Collins is a good fly-fisherman; and fly-fishermen, unless they are naturalists, are generally very positive. How often have I tried to teach anglers that the May-fly does not come from a caddis worm; how often have I failed! Well, the two-winged fly I have just found in such thousands, with their dead bodies brooding over this mass of eggs, is known to entomologists by the name of _Atherix Ibis_; the females are gregarious, and, as we have seen, attach their eggs to rails, boughs, or other objects overhanging streams; each female, having laid her eggs, remains there and dies; shortly after comes another and does the same, and so on till immense clusters are formed. The larva, when hatched, falls into the water, its future residence; it is said to have a forked tail about one third the length of its body, and to "have the power of raising itself in the water by an incessant undulating motion in a vertical plane." I am not, however, acquainted with either larva or pupa, but hope to become so this summer. "It is very curious, papa," said Jack, "that the flies, after they have laid their eggs, should die there; why do not they fly away? Do any other animals do the same?" Yes, pretty much so. Some of the female insects of the genus called _Coccus_, scale insect, or mealy bug, common on the stems of various trees, to which they sometimes do incredible mischief, lay their eggs and die over them, the dead bodies of the parents forming coverings for the young. See how fast the green drake is appearing. Notice how it flies with head erect for a second or two, and then falls almost helplessly on the surface of the water.

There! did you see that fish rise at him? He has escaped the hungry trout, and has reached a blade of grass, where he will probably rest for some hours. But give me my rod; perhaps the same trout will rise at my artificial fly. There! that throw was exactly over the spot. No; he won't have it. I'll try again and again. No. Objects to _sauce piquante_, I suppose. Well, I will tempt him again in an hour's time or so. The water is smooth here, and free from rapids; let us lie down on the grass and see the birth of _Ephemera_--for that is the May-fly's proper name. Here comes something floating down. It is within the reach of my hand, so I will secure it. What is it? As I thought. Ephemera is throwing off its swaddling clothes. See how it twirls and twists itself about. Now it is free; and the strange-looking worm has changed into a beautiful fly. But there is yet one other operation to go through ere it assumes its final and complete form; you see at present it is a heavy flier, for the wings are scarcely dry, and the muscles as yet unequal to great exertion; so in their present imperfect form they are constantly dropping for a second or two in the water, and are often sucked down the throat of some roach, trout, or other fish on the look-out. You should remember that the _Ephemera_, or May-fly, in this its _sub-imago_, or imperfect winged state, represents the "green drake" of the angler. What have I here on this blade of grass? Do you see? What is the shadowy form that lifelessly clings to it? It is a delicate membrane, thin and light; see, I blow it away. You saw the split in the back, through which the former tenant left the abode. It is the cast-off skin of the green drake, now metamorphosed into a creature more active than harlequin or columbine, the male into a dark brown insect, with gauze-like wings, the female into a beautiful creature, with body marbled white and brown, and able to fly well and strongly, now high in the air, now sailing along close to the surface of the water, ever and anon dipping gently into it for the purpose of laying her eggs. The small oval eggs sink down to the bottom, and attach themselves to the weeds and stones that are found there. The flight of the male Ephemera is different; it is the males that practise together that peculiar up-and-down dance, with heads erect and bodies curving prettily upwards; of course, you can understand how countless multitudes fall victims to fish and bird, for dainty morsels they are. These flies, though voracious feeders both in the larval and nymphal state, never eat at all after they have assumed their perfect form. Indeed, they have no true mouth, only an imperfect or rudimentary one; and you would never find a particle of food in their stomachs, which are always more or less full of air-bubbles, which, no doubt, assist in buoying up the insect, and thus save the expenditure of muscular power. I'll catch one of those dancing males, and press him quickly in the middle. There! crack he goes! for the little air-bubbles in the stomach have burst by the pressure of my finger and thumb.

Abundant as are the May-flies at the latter end of May and the beginning of June in this country, in other countries they are sometimes more astonishingly numerous. In some parts of Holland, Switzerland, and France, their great numbers have been compared to pelting flakes of snow. "The myriads of Ephemeræ which filled the air," says Reaumur, "over the current of the river and over the bank on which I stood, are neither to be expressed nor conceived. When the snow falls, with the largest flakes and with the least interval between them, the air is not so full of them as that which surrounded the Ephemeræ." The occurrence of such prodigious numbers is, I believe, unknown in the British isles. In the perfect or _imago_ state the May-fly lives but a short time. The word _ephemera_ means "living only for a day;" and though individuals may live longer, yet the term is fairly correct as expressing their short existence. The May-flies (_Ephemeræ_) have all three long fine hairs at the end of the tail; some members of the same family, but belonging to a different genus, have only two hair-like appendages. For instance, the fly known to fishermen as the "March-brown" belongs to the same family as the May-fly; it is smaller than it, and has only two hairs at the end of the tail; but with this exception, the natural March-brown and the May-fly are wonderfully alike; yet it is most curious to notice what a wonderful difference there is in the larvæ of these two insects. Significant facts, no doubt, lie at the bottom of such differences in the case of insects so evidently allied, but these I will not speak of. Here are the two forms of larvæ, the one being the larva of the common May-fly (_Ephemera_), the other that of the March-brown (_Baëtis_).