"When the jay goes to drink," the narrative proceeds, "his messmate very impudently jumps into the water to wash herself, throwing it in showers over her companion, who bears it all patiently; venturing now and then to take a sip between every splash, without betraying the smallest irritation. On the contrary, he seems to take pleasure in his little fellow-prisoner allowing her to peck (which she does very gently) about his whiskers, and to clean his claws from the minute fragments of chesnuts which happen to adhere to them*." Ducks and other water-birds are, if possible, more assiduous in trimming their feathers than land-birds, one reason for which appears to be, that their plumelets being of very close texture, any slight derangement in them is readily felt from the air getting access to the skin through the breach thence occasioned. The closeness of feather in aquatic birds serves to present an impenetrable texture to the water in which they swim, as well as a smooth surface which diminishes the effects of friction in their progress. The greater number of authors, in addition to this, tell us that birds, and more particularly aquatic birds, dress their feathers with a peculiar oil furnished for this purpose by a gland on the rump; but this is an opinion which we shall presently see admits of considerable doubt. It may be well, however, to state the particulars of the common notion. " Upon the rump," says Willughby, "grow two glandules, designed for the preparation and secretion of a certain unctuous humour, and furnished with a hole or excretory vessel. About this hole grows a tuft of small feathers or hairs, somewhat like to a painter's pencil. When, therefore, the parts of the feathers are shattered, ruffled, or any way discomposed, the bird, turning *Wilson, Amer. Ornith. i. 15. by the side of the river; and I am sure I hardly took a step that did not delight me; I have brought my handkerchief full of curiosities home." In the account which the observant boy subjoins of his interesting ramble (the other had nothing to tell) over the heath and the meadows, it is remarkable that Birds constitute more than two-thirds of his story. He saw a wheat-ear hopping about a pile of stones; a flock of lapwings throwing their fantastic somersets in the air, and one of them tumbling along as if her wing had been broken to lure him from her nest; he saw a king-fisher with its splendid plumage of green, orange, and blue, darting after fish in the brook, along the margin of which a family of sandpipers were hunting down aquatic insects, while some swallows which skimmed along on the wing were ready to dart upon the flies which escaped from these swift-footed pedestrians; he saw bank-swallows burrowing in the bank to shelter their nests from bad weather and worse enemies; he saw a heron take her patient stand at a bend of the river to watch for a passing fish, and, after a successful capture, fly off with her prey to her nest in the woods; and he saw a troop of starlings as numerous as a swarm of bees,the same phenomenon which nearly three thousand years before had afforded Homer a fine poetical simile for a troop of fugitive warriors. "So it is," the narrative concludes" one man walks through the world with his eyes open, and another with them shut; and upon this difference depends all the superiority of knowledge the one acquires above the other." There are few persons, even of the well-informed, who, like the school-boy with "his eyes open," take an interest in such common occurrences as a wheat-ear hopping over stones, or a swallow hawking for flies over a brook. A taste for natural objects must be awakened and cultivated, before enjoyment tails (Gallus ecaudatus, TEMMINCK), originally it would appear from Ceylon *, the tail, the rump, and the gland are all wanting, the part where these grow in other species being depressed and smooth. Were an attempt made to assign a reason why these Ceylonese fowls have no unctuous gland on the rump, a mistake might as readily be committed as has, it would appear, been done in the theory framed to account for the use of the gland in birds which possess it. All the works of nature being lavishly filled with wonders, fitted to raise most just admiration of the Creator, those who, with very laudable intentions, undertake to exhibit these won*Temminck, Hist, des Pig. et Gall. ii. 267. ders, may be considered as in some degree blameable when they introduce into their enumeration circumstances that are vague and uncertain. Among such doubtful things appears to be the opinion that the feathers of birds require to be done over with a kind of oil or grease, in order to cause the rain or other water to run off without penetrating them, the unction, when wanted, being supplied by the gland on the rump. If those who adopt this opinion, plausible as it seems to be, had taken the trouble to ascertain the small quantity of fluid actually secreted by this gland from day to day, and compared it with the proportional extent of surface constituted by the assemblage of the numberless feathers of any particular bird, not to speak of the instrument with which the dressing is said to be effected, they would have seen at once that the theory is untenable, as the quantity secreted in one day would scarcely suffice to anoint a single feather, much less the whole. We have just squeezed out all the oil contained in the double rump gland of a common wren, and found it impossible to make it go over one of the tail feathers *. One fact," says M. Le Vaillant, "is frequently sufficient to demolish a theory +;" and the fact that the feathers of the rumpless fowls which have no gland are as smooth and proof against rain as those which possess the gland, furnishes a striking illustration of the remark. 66 The fact, however, is unquestionable that birds are sometimes seen pecking about the gland in question. But the observing of a bird thus engaged, so far from authorizing the received conclusion, might have shown that the point of the bill could never squeeze out enough of fluid for the purpose alleged. The only legitimate inference would have been that some slight pain or irritation had caused the bird to peck the gland; and every school+ Hist. Nat, des Perroouets, i. 20. * J. R. boy knows that the canal of this gland often becomes obstructed in his pet birds, and occasions a troublesome and sometimes fatal engorgement *. The remark of Blumenbach † that the gland is largest in aquatic birds, contains a generalization not warranted by facts; for grebes, divers, and such as want tails, have the gland much smaller ‡, though their feathers are as smooth and as impenetrable by water as those of the terns and the gulls which have considerable tails. It is only requisite, indeed, for any one to watch a bird preening its feathers, to be convinced of the fallacy of the theory. We have attended for hours to varfous species of birds when thus engaged; and so far from constantly returning to the rump-gland, which by the hypothesis would be indispensable for dressing every successive feather, it is rarely visited at all during the operation, and when it is, the sole object seems to be to trim the pencil of feathers which surrounds the gland §. Had we any doubts upon the subject, the simple experiment of covering the gland in one hen or duck so as to prevent the bird having access to it, and leaving it uncovered in another, for a few days or weeks, would, by the state of the feathers in each, set the question at rest. Independently of such an experiment, common to all birds, the circumstance of the feathers on the head being equally trim, smooth, and glossy with those on the body, though they cannot be oiled, as it is impossible to reach the head with the bill-the only instrument by which the oil could be applied-is of itself fatal to the theory. Should we be asked what we consider to be the use of the gland, we must at once say that we do *Raumur, Oiseaux Domestiques, ii. 332. + See p. 4. § J.R. |