“I have seen the cock parrakeet regularly feed the hen, by first filling his own crop, and then supplying her from his beak. Parrots, macaws, cockatoos, &c., when they are very fond of the person who feeds them, may likewise be observed to have the action of throwing up the food, and often do it. The cock pigeon, when he caresses the hen, performs the same kind of action as when he feeds his young, but I do not know if at this time he throws up anything from the crop.

“During incubation, the coats of the crop in the pigeon are gradually enlarged and thickened, like what happens to the udder of females of the class mammalia, in the term of uterine gestation. On comparing the state of the

crop when the bird is not sitting, with its appearance during incubation, the difference is very remarkable. In the first case it is thin and membranous, but by the time the young are about to be hatched, the whole, except what lies on the trachea or windpipe, becomes thickened, and takes on a glandular appearance, having its internal surface very irregular. It is likewise evidently more vascular than in its former state, that it may convey a quantity of blood, sufficient for the secretion of this substance, which is to nourish the young brood for some days after they are hatched. Whatever may be the consistence of this substance when just secreted, it most probably soon coagulates into a granulated white curd, for in such a form I have always found it in the crop; and if an old pigeon is killed just as the young ones are hatching, the crop will be found as above described, and in its cavity pieces of white curd, mixed with some of the common food of the pigeon, such as barley, beans, &c.

“If we allow either of the parents to feed the young, its crop, when examined, will be discovered to contain the same curdled substance, which passes thence into the stomach, where it is to be digested. The young pigeon is fed for some time with this substance only, and about the third day some of the common food is found mingled with it; and as the pigeon grows older, the proportion of common food is increased, so that by the time it is seven, eight, or nine days old, the secretion of the curd ceases in

the old ones, and of course will no more be found in the crop of the young.

“It is a curious fact that the parent pigeon has at first the power to throw up this curd without any mixture of common food, although afterwards both are thrown up according to the proportion required for the young ones. I have called this substance curd, not as being literally so, but as resembling that more than anything I know; it may, however, have a greater resemblance to curd than we are perhaps aware of; for neither this secretion, nor curd from which the whey has been pressed, seem to contain any sugar, and do not run into the acetous fermentation. The property of coagulating is confined to the substance itself, as it produces no such effect when mixed with milk. This secretion in the pigeon, like all other animal substances, becomes putrid by standing, though not so readily as either blood or meat, it resisting putrefaction for a considerable time; neither will curd much pressed become so putrid as soon as either blood or meat.”

Selby says,[107] “The young remain in the nest till they are able to fly, and are fed by the parent birds, who disgorge into their mouths the food that has undergone a maceration, or semi-digestive process, in that part of the œsophagus usually called the crop or craw.”

Colonel Montagu appears to be one of the few original

observers who has confirmed the account given by Hunter. “The rook,” he says, “has a small pouch under the tongue, in which it carries food to its young. It is probable the use of the craw may be extended further than is generally imagined, for, besides the common preparation of the food to assist its digestion in the stomach, there are some species that actually secrete a lacteal substance in the breeding season, which, mixing with the half-digested food, is ejected to feed and nourish the young. The mammæ from which this milky liquor is produced, are situated on each side of the upper part of the breast, immediately under the craw. In the female turtle-dove we have met with these glands tumid with milky secretion, and we believe it common to both sexes of the dove genus.”[108]

THE BARBARY PIGEON.