they will never return to the same place without having sent out one single scout first, and a party of scouts afterwards; and when the reconnoitring party returns and reports that there is no danger, a second group of scouts is sent out to verify the first report, before the whole band moves. With kindred species the cranes contract real friendship; and in captivity there is no bird, save the also sociable and highly intelligent parrot, which enters into such real friendship with man. "It sees in man, not a master, but a friend, and endeavours to manifest it," Brehm concludes from a wide personal experience. The crane is in continual activity from early in the morning till late in the night; but it gives a few hours only in the morning to the task of searching its food, chiefly vegetable. All the remainder of the day is given to society life. "It picks up small pieces of wood or small stones, throws them in the air and tries to catch them; it bends its neck, opens its wings, dances, jumps, runs about, and tries to manifest by all means its good disposition of mind, and always it remains graceful and beautiful."(21) As it lives in society it has almost no enemies, and though Brehm occasionally saw one of them captured by a crocodile, he wrote that except the crocodile he knew no enemies of the crane. It eschews all of them by its proverbial prudence; and it attains, as a rule, a very old age. No wonder that for the maintenance of the species the crane need not rear a numerous offspring; it usually hatches but two eggs. As to its superior intelligence, it is sufficient to say that all observers are unanimous in recognizing that its intellectual capacities remind one very much of those of man.
The other extremely sociable bird, the parrot, stands, as known, at the very top of the whole feathered world for the development of its intelligence. Brehm has so admirably summed up the manners of life of the parrot, that I cannot do better than translate the following sentence:—
"Except in the pairing season, they live in very numerous societies or bands. They choose a place in the forest to stay there, and thence they start every morning for their hunting expeditions. The members of each band remain faithfully attached to each other, and they share in common good or bad luck. All together they repair in the morning to a field, or to a garden, or to a tree, to feed upon fruits. They post sentries to keep watch over the safety of the whole band, and are attentive to their warnings. In case of danger, all take to flight, mutually supporting each other, and all simultaneously return to their resting-place. In a word, they always live closely united."
They enjoy society of other birds as well. In India, the jays and crows come together from many miles round, to spend the night in company with the parrots in the bamboo thickets. When the parrots start hunting, they display the most wonderful intelligence, prudence, and capacity of coping with circumstances. Take, for instance, a band of white cacadoos in Australia. Before starting to plunder a corn-field, they first send out a reconnoitring party which occupies the highest trees in the vicinity of the field, while other scouts perch upon the intermediate trees between the field and the forest and transmit the signals. If the report runs "All right," a score of cacadoos will separate from the bulk of the band, take a flight in the air, and then fly towards the trees nearest to the field. They also will scrutinize the neighbourhood for a long while, and only then will they give the signal for general advance, after which the whole band starts at once and plunders the field in no time. The Australian settlers have the greatest difficulties in beguiling the prudence of the parrots; but if man, with all his art and weapons, has succeeded in killing some of them, the cacadoos become so prudent and watchful that they henceforward baffle all stratagems.(22)
There can be no doubt that it is the practice of life in society which enables the parrots to attain that very high level of almost human intelligence and almost human feelings which we know in them. Their high intelligence has induced the best naturalists to describe some species, namely the grey parrot, as the "birdman." As to their mutual attachment it is known that when a parrot has been killed by a hunter, the others fly over the corpse of their comrade with shrieks of complaints and "themselves fall the victims of their friendship," as Audubon said; and when two captive parrots, though belonging to two different species, have contracted mutual friendship, the accidental death of one of the two friends has sometimes been followed by the death from grief and sorrow of the other friend. It is no less evident that in their societies they find infinitely more protection than they possibly might find in any ideal development of beak and claw. Very few birds of prey or mammals dare attack any but the smaller species of parrots, and Brehm is absolutely right in saying of the parrots, as he also says of the cranes and the sociable monkeys, that they hardly have any enemies besides men; and he adds: "It is most probable that the larger parrots succumb chiefly to old age rather than die from the claws of any enemies." Only man, owing to his still more superior intelligence and weapons, also derived from association, succeeds in partially destroying them. Their very longevity would thus appear as a result of their social life. Could we not say the same as regards their wonderful memory, which also must be favoured in its development by society—life and by longevity accompanied by a full enjoyment of bodily and mental faculties till a very old age?
As seen from the above, the war of each against all is not the law of nature. Mutual aid is as much a law of nature as mutual struggle, and that law will become still more apparent when we have analyzed some other associations of birds and those of the mammalia. A few hints as to the importance of the law of mutual aid for the evolution of the animal kingdom have already been given in the preceding pages; but their purport will still better appear when, after having given a few more illustrations, we shall be enabled presently to draw therefrom our conclusions.
NOTES:
1. Origin of Species, chap. iii, p. 62 of first edition.
2. Nineteenth Century, Feb. 1888, p. 165.
3. Leaving aside the pre-Darwinian writers, like Toussenel, Fee, and many others, several works containing many striking instances of mutual aid—chiefly, however, illustrating animal intelligence were issued previously to that date. I may mention those of Houzeau, Les facultes etales des animaux, 2 vols., Brussels, 1872; L. Buchner's Aus dem Geistesleben der Thiere, 2nd ed. in 1877; and Maximilian Perty's Ueber das Seelenleben der Thiere, Leipzig, 1876. Espinas published his most remarkable work, Les Societes animales, in 1877, and in that work he pointed out the importance of animal societies, and their bearing upon the preservation of species, and entered upon a most valuable discussion of the origin of societies. In fact, Espinas's book contains all that has been written since upon mutual aid, and many good things besides. If I nevertheless make a special mention of Kessler's address, it is because he raised mutual aid to the height of a law much more important in evolution than the law of mutual struggle. The same ideas were developed next year (in April 1881) by J. Lanessan in a lecture published in 1882 under this title: La lutte pour l'existence et l'association pour la lutte. G. Romanes's capital work, Animal Intelligence, was issued in 1882, and followed next year by the Mental Evolution in Animals. About the same time (1883), Buchner published another work, Liebe und Liebes-Leben in der Thierwelt, a second edition of which was issued in 1885. The idea, as seen, was in the air.
4. Memoirs (Trudy) of the St. Petersburg Society of Naturalists, vol. xi. 1880.
5. George J. Romanes's Animal Intelligence, 1st ed. p. 233.
6. Pierre Huber's Les fourmis indigees, Geneve, 1861; Forel's Recherches sur les fourmis de la Suisse, Zurich, 1874, and J.T. Moggridge's Harvesting Ants and Trapdoor Spiders, London, 1873 and 1874, ought to be in the hands of every boy and girl. See also: Blanchard's Metamorphoses des Insectes, Paris, 1868; J.H. Fabre's Souvenirs entomologiques, Paris, 1886; Ebrard's Etudes des moeurs des fourmis, Geneve, 1864; Sir John Lubbock's Ants, Bees, and Wasps, and so on.
7. Forel's Recherches, pp. 244, 275, 278. Huber's description of the process is admirable. It also contains a hint as to the possible origin of the instinct (popular edition, pp. 158, 160). See Appendix II.
8. The agriculture of the ants is so wonderful that for a long time it has been doubted. The fact is now so well proved by Mr. Moggridge, Dr. Lincecum, Mr. MacCook, Col. Sykes, and Dr. Jerdon, that no doubt is possible. See an excellent summary of evidence in Mr. Romanes's work. See also Die Pilzgaerten einiger Sud-Amerikanischen Ameisen, by Alf. Moeller, in Schimper's Botan. Mitth. aus den Tropen, vi. 1893.
9. This second principle was not recognized at once. Former