Part 6 (1/2)
The next thing is to poison the skin. Do this with a mixture of powdered a.r.s.enic and alum, in equal parts. Some of our most extensive collectors use no alum, simply pure a.r.s.enic in liberal quant.i.ty; but I consider that the use of alum also is always desirable, and under certain conditions it is extremely so. Some collectors use a.r.s.enical soap exclusively, even on small birds, and on large birds I, too, have used it quite extensively, supplemented by an immediate sprinkling of powdered alum, to do the curing of the skin. For genuine thoroughness in poisoning and preserving, I will back a.r.s.enical soap and alum against all other substances the world can produce; but in treating _small birds that are to be made up as dry skins_, I prefer and recommend powdered a.r.s.enic and alum, as stated above.
Whatever poison you decide to use, apply it thoroughly to every part of the skin, the skull, wings, legs, and tail. Now put a ball of cotton in each eye-socket to fill up the cavity, and you are ready to reverse the skin and bring it right side out once more. It is usually some trouble to get the skin back over the skull, and that I accomplish in this wise:
Let the skin rest on the edge of the table, place both of your thumbs on the back of the skull, and with all your fingers and finger-nails, reach forward and begin to crowd the skin of the head back where it belongs. At the same time, you must push on the skull with your thumbs, as if trying to push it into the neck, and in a very short time, by a combination of coaxing and crowding, the skin made pa.s.ses the critical point on the skull, and, presto! the whole skin is right side out once more. Now take it by the bill and give it a gentle shaking to stir up the feathers so that they will fall back naturally. Pluck outward the cotton in the orbit into the opening of the eye, to imitate the round fulness of the eyeball.
The wing bones of very small birds need not be wrapped with cotton, but the leg bones should be, always. Now take a bunch of cotton batting of the right size, and roll it between the palms until it attains the proper size to fill the neck, and is a trifle longer than the entire body and neck.
Fold over one end of this, take it between the points of your forceps, insert it through the neck, and into the cavity of the skull. Tuck up the other end at the tail, and give the cotton body its right length. Then in the middle of the skin, pull the cotton roll apart sidewise, spread it out and lay on it a ball of cotton to form the body.
Next, take hold of the broken humerus with the forceps, and pull it inward until the joint of the wing appears, and the two humeri lie parallel and close to each other. This draws the wings into place.
Be sure to put enough cotton in the body of a skin; for a little plumpness and rotundity is desirable in a small skin. Avoid making cylindrical bird skins; avoid the East Indian native habit of crowding the breast of a bird clear up into its neck, and also avoid stretching a skin.
We have now to finish the head by inserting a little bunch of cotton in the throat, until that part is properly filled, and plucking out or cutting off the surplus. The mandibles must be held together by a thread or a pin until they have dried in position. Next adjust the wings, legs, and tail. The tail should be slightly spread, and there are two ways of doing this. One is to reverse the natural overlapping of the tail feathers, which is the quickest way, and quite satisfactory. The other is to lay the skin on a board, put a pin through each corner of the ”pope's nose,” spread the tail, and thrust the pins into the board until the skin is dry. Finally, tie on your label, which should be as small as possible to contain the necessary data--locality, date, s.e.x, number, collector's name, measurements, and remarks. Some collectors label only with numbers, corresponding with recorded data in a note-book; but it is a bad plan. Note-books often get lost, and then such specimens lose half their value.
[Ill.u.s.tration: FIG. 13.--The Bird Skin in Position.]
WRAPPING UP A SKIN.--There are various ways of ”laying out” bird skins. The best is to wrap each skin in a very thin sheet of cotton batting or wadding, which draws with the softness of down, and yet, when pinched or twisted at the ends, it holds every feather in place. The bird skins prepared by Mr. William Palmer, one of the National Museum taxidermists, are fine examples of how skins should be made. Mr. Palmer's method of shaping and wrapping up a small skin is as follows, and the accompanying figures are from specimens prepared by him: Take the skin up between the left thumb and forefinger, at the shoulders, and pinch it together, while with the small forceps you adjust the scapulars over the point of the wings. Cross the feet, lay the skin breast downward on a thin sheet of cotton batting of the proper dimensions, and arrange the feathers of the back, the wings, etc. (Fig. 13). Then lift the outer edge of the sheet of cotton, bring it forward over the skin toward the operator, so that it will cover the back (Fig. 14). Next, lift the inner edge of the cotton sheet, draw it with gentle pressure to make the skin of the right size, and lap it well over the other. The two edges of the cotton sheet will stick together very well by simply overlapping them.
[Ill.u.s.tration: FIG. 14.--The Skin Half Wrapped.]
The head can be adjusted by pulling on the cotton at that end, and pinching the end together beyond the head. The bill must be set at the proper angle, and held by catching the point in the cotton. Do not let the bill point straight out, for it will stretch the skin of the throat too much; neither should it point up at a right angle to the body, for the tip will be catching in everything that comes near it. The best way with most short-billed birds is to let the bill point at an angle of about forty-five degrees to the axis of the body. Beaks that are very long require special arrangement, as shown in Figs. 17 and 18.
Now lift the wrapped-up skin, lay it with the tail toward you, breast uppermost, and with both hands tear the cotton open in a straight line up to the base of the tail (Fig. 15). You can now spread the tail by overlapping the feathers, or leave it closed if you prefer. See that your label is on, adjust the toes and legs carefully, then fold over the edges of the cotton and overlap them, and the skin is done (Fig. 16). Always spread the toes of all swimming-birds.
Another plan is to dispose of each skin in a little cylinder of paper, made to fit, of course. This is the best plan when you are far from the conveniences of home, and in a hurry. The effect of this, however, is to produce a cylindrical skin, which is not a prize shape. Still another way is to make a small cornucopia of stiff paper, and slip the skin into it, head first, after which the large end is closed by bending in the edges.
The old-fas.h.i.+oned, corrugated drying-board is an excellent resource when you are in a great hurry with a number of specimens.
[Ill.u.s.tration: FIG. 15.--Spreading the Tail.]
[Ill.u.s.tration: FIG. 16.--The Skin fully Wrapped.]
The ill.u.s.tration on p. 56 (Fig. 17), from one of Mr. Palmer's specimens, shows the shape a small skin should have to be considered perfect.
Freshly made bird skins should never be subjected to crowding or pressure, nor should old skins either, for that matter. If you go far afield, and expect to collect hundreds of skins, you should go provided with a light and strong chest, either made to open at one side and contain a series of shallow drawers to receive skins, or else, which is the next best thing, and very easily made, a box containing a series of shallow tills of varying depth, standing one upon another from bottom to top. Each drawer or till should be made just deep enough to hold skins of a certain size, but no more, or else in travelling the skins will tumble about. Remember it is useless to try to make large collections of good skins in the field unless you can take care of your finished specimens. This is for specimens freshly prepared and _not yet dry_. After skins become thoroughly dry, they can be packed ”in bulk,” in a chest or trunk, by putting the largest at the bottom, and filling the cavities with the small skins which cannot stand so much pressure. Bird skins should always be packed in cotton when they are to be s.h.i.+pped, giving to each a soft, comfortable resting-place, and the box must be filled full, so that there will be no tossing about.
[Ill.u.s.tration: FIG. 17.--A Perfect Bird Skin.]
DETERMINATION OF s.e.x IN BIRDS.--To a collector who is working under difficulties this often seems like the very ”last straw upon a camel's back;” but it must be attended to in every case wherein the s.e.x of the bird is not clearly and unmistakably indicated by the plumage. If you can, get an experienced ornithologist to show you how to determine the s.e.x in difficult subjects (_e.g._, young birds, or birds midway between two breeding seasons). But there are ways in which we can help ourselves. If you begin with birds during or near the breeding season, you will have plain sailing long enough to become familiar with the subject.
In birds the organs of generation lie close up to the lumbar vertebrae, near the kidneys, in the region called ”the small of the back.” The best way to reach this region for examination is to make a cut clear across the wall of the abdomen, break the back over at the last pair of ribs, and the intestines will at once fall down, exposing the lumbar region. You will then see the kidneys--two large, dark-brown ma.s.ses situated in the concavity of the sacrum--and on their surface, at the upper end, lie the reproductive organs. The t.e.s.t.i.c.l.es of the male are two dull, whitish, ellipsoidal, or nearly round bodies, of the same size, lying close together. The sign for this s.e.x is the astronomical sign for the planet Mars [Male].
The ovary of the female is, except during the breeding season, the most difficult to distinguish. Look first for a little bunch of minute round globules, of varying sizes and grayish white color. In the breeding season the eggs are easily found. Failing in that, you must look for the ovary itself, which, when found, will be recognized as a little, irregular, flattish bunch of a light gray color. If you search with a magnifying-gla.s.s, you may be able to detect it by its peculiar granulated appearance. The sign for the female is the sign for the planet Venus [Female].
FOOTNOTE:
[5] From Steele's Popular Zoology, by permission of the American Book Company.
CHAPTER VII.