70 FIELD ORNITHOLOGY part i 



with which at any rate we have nothing to do in this connection. 

 They occur in both sexes, and if the testicles are not immediately 

 seen, or the ovary not at once recognised, they might easily be 

 mistaken for testicles. Observe that, instead of lying in front, they 

 cap the kidneys ; that they are usually yellowish instead of opaque 

 whitish ; and that they have not the firm, snaooth, regular sphericity 

 of the testicles. The testes, however, vary more in shape and 

 colour than might be expected, being sometimes rather oblong or 

 linear, and sometimes grayish or livid bluish, or reddish. There is 

 occasionally but one. The sex determined, use the sign $ or ? to 

 designate it, as already explained. 



Recognition of Age is a matter of ornithological experience 

 requiring in many or most cases great familiarity with birds for its 

 even approximate accomplishment. There are, however, some un- 

 mistakable signs of immaturity, even after a bird has become full- 

 feathered, that persist for at least one season. These are, in the 

 first place, a peculiar soft fluffy feel of the plumage ; the feathers 

 lack a certain smoothness, density, and stiffening which they subse- 

 quently acquire. Secondly, the bill and feet are softer than those 

 of the adults ; the corners of the mouth are puffy and flabby, the 

 edges and point of the bill are dull, and the scales, etc., of the legs 

 are not sharply cut. Thirdly, the flesh itself is tender and pale 

 coloured. These are some of the points common to all birds, and 

 are independent of the special markings that belong to the youth of 

 particular species. Some birds are actually larger for a Avhile after 

 leaving the nest than in after years when the frame seems to shrink 

 somewhat in acquiring the compactness of senility. On the other 

 hand, the various members, especially the bill and feet, are propor- 

 tionally smaller at first. Newly growing quills are usually recog- 

 nised on sight, the barrel being dark coloured and full of liquid, 

 while the vanes are incomplete. In studying, for example, the 

 shape of a Aving or tail, there is always reason to suspect that the 

 natural proportions are not yet presented, unless the quill is dry, 

 colourless, and empty, or only occupied with shrunken white pith. 



Examination of the Stomach frequently leads to interesting 

 observations, and is always worth while. In the first j^lace, we 

 learn most unquestionably the nature of the bird's food, which is a 

 highly important item in its natural history. Secondly, we often 

 secure valuable specimens in other departments of zoology, particu- 

 larly entomology. Birds consume incalculable numbers of insects, 

 the harder kinds of which, such as beetles, are not seldom found 

 intact in their stomachs ; and a due percentage of these represent 

 rare and curious species. The gizzards of birds of prey, in particular, 

 should always be inspected, in search of the small mammals, etc., 

 they devour ; and even if the creatures are unfit for preservation. 



