(c) The neck.—In the feathered bird this appears short; it will be better seen after the removal of the feathers (contour feathers) which cover it.
(d) The trunk.—What is the apparent shape of the trunk? Where is its heaviest part?
(e) The wings.—Open out the wings fully and measure the distance from tip to tip; compare it with the length of the trunk. Which surface, upper or lower, of the expanded wing is rounded (convex) and which is hollowed (concave)? Put up an umbrella and, holding it by the handle, move it quickly (i) away from you, (ii) towards you. In which direction of motion does the air offer more resistance? Is it an advantage for the expanded wing to be convex above and concave below? Why? Feel the wing-bones through the skin, and notice that the wing-skeleton consists of three parts corresponding to the bones of your upper-arm, fore-arm, and hand (with the wrist) respectively; and that they are bent on each other in the form of a Z when the wings are folded. The large quill-feathers attached to the segment which corresponds to the hand and wrist are called primaries; count them. Those attached to the fore-arm are called secondaries; count them. Find the tuft of smaller feathers which spring, at the front edge of the wing, from the thumb; this tuft is called the thumb-wing. The primaries and secondaries collectively may be called the rowing feathers. Notice the smaller feathers which, on both the upper and lower surface of the wing, cover the quills of the primaries and secondaries; these smaller feathers are called the wing-coverts.
(f) The legs.—Feel the leg-bones through the skin, and make out the various segments. Is the whole of the hind-limb feathered? Which part is devoid of feathers? With what is this part covered? How many toes are there? Do any point backwards? Stretch out the legs and notice that the toes open. Bend the ankle-joint and notice that the toes close automatically. Of what use is this in perching?
(g) The tail.—Examine the tail and notice the large quill-feathers attached to it; count them. As they are largely used for steering during flight they are sometimes called the steering feathers.
3. The feathers.—Examine the arrangement of the feathers. The short feathers which clothe the body generally are called contour feathers because they determine the contour of the unplucked bird; remove one or two and place them aside. The feathers which cover the bases of the large quills are called coverts—wing-coverts or tail-coverts according to their position. Remove one or two for future examination. Examine the arrangement of the quill-feathers of the wings, and notice how the vane or web of one partially overlaps the next. The vane is supported by a shaft. Are the two sides of the vane of equal width? Is the narrower side directed forwards or backwards? Pull out a quill-feather from each wing and compare them. How could you recognise, if you did not know, whether any particular feather had come from the right or from the left wing? Pull out a quill-feather from the tail; are the sides of the vane of equal width?
4. Examination of various feathers.—Examine in detail a quill-feather from the wing. Make out:
(a) The quill.—Is it hollow or solid? Try to bend it and notice its great strength. Observe the small hole at its base.
(b) The shaft.—This is the prolongation of the quill, and carries the web or vane. Is the shaft hollow or solid? Notice the small tuft of down on the inner face of the feather, at the junction of the quill and shaft.
(c) The vane.—Hold up the feather to the light and examine the vane with a lens. Notice that the vane consists of a number of laths which spring from the shaft; these are called barbs. Try to separate the barbs, and observe that they offer considerable resistance to the pull, as if they were somehow fastened together. Examine a barb with a strong lens and observe the finer branches, called barbules, which it bears. The barbules on one side of the barb carry little hooks, while those of the other side bear flanges, on which fit the hooks of barbules carried by the next barb below. The hooks and flanges cannot be seen without a microscope.