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America (Corresponding members limited)

3. Corresponding members, limited to 100 in number; and 4. Associate members, who must be residents of North America, and are not limited as to number. The total membership of the Union in December, 1894, was 616. Annual meetings are held, usually in Washington, New York, or Cambridge. The Auk, the official organ of the Union, is a quarterly journal under the editorship of Dr. J. A. Allen, at the American Museum of Natural History. case will it be difficult to decide in which of these groups a bird belongs. Now glance over the illustrations and select the one which you think most nearly resembles the bird you are identifying. At Crown Auriculars Forehead Lores Bill Chin Back Nape Scapulars Lesser coverts of wing Middle coverts a Greater coverts Tertials Secondaries Flanks Tibia Outer tail-feather Tail-feathers Upper lail-coverts Under tail-coverts ( First primary Rump Primaries Tarsus Belly Sides FIG. 2.-Topography of a bird. (Bluebird, slightly reduced). Breast Throat USE OF THE KEYS. the most highly developed ones, Thrushes, Bluebirds, etc. Two main divisions are given: first, Water Birds; second, Land Birds. In no USE OF THE KEYS. each step test your decision by reading the brief diagnoses of orders and families. In this way you may readily place your bird in its proper family.

The Keys to Species. - If a bird always wore the same plumage it would be a comparatively easy matter to place it in a certain section a b C d FIG. 3.-Spotted (a), streaked (b), barred (c), and margined (d) feathers. of a key and keep it there. But, unfortunately, not only are the males and females of the same species frequently quite unlike, and the young different from either, but their plumages may vary with the season. Thus, you see, a bird's color is a most uncertain quantity. An individual of a given species may not only wear two very different costumes, but, in doffing one for another, he does it gradually, and in the meantime appears in changing or transition plumage. For this reason it has been customary to base keys on only adult males. Such keys do very well in the nesting season, when birds are in song, and when males constitute probably nine tenths of the birds one sees. But at other times of the year young birds outnumber the old ones, and the adults themselves may lose their breeding plumage and wear quite a different one. I have, therefore, attempted to make keys which will identify a bird in any plumage. To do this it was necessary to use many more specimens than there were species. For example, the key to our some 40 species of Warblers is based on 110 specimens representing as many phases of plumage.

With identification as the sole end in view I have, in the keys, abandoned all attempts to follow the current system of classification, and, taking color as the most tangible character, have to a great extent arranged the species on this character alone. The result, from the systematist's standpoint, is most unnatural. Species of different genera USE OF THE KEYS. are brought into the same subsections, and the more variable species may be placed in several widely separated sections.

The maker of keys, however, should not try to serve two masters. If the keys will identify, they will have accomplished their purpose. The classification of our birds is shown in the body of the book, where the species are arranged according to the system adopted by the American Ornithologists' Union. In making these keys the birds are first assorted into several major sections or groups, according to the markings of some one part of the body. Each one of these sections is preceded by the same kind of number or letter. The heading of a group or section applies to all the species included in it. Thus, if I does not apply to the bird you are identifying, you must pass at once to II, or III, or IV, as the case may be. In like manner, if the bird does not fall into sections 1, A, or a, we go to 2, B, or b, respectively. Even should the first section describe your bird, it is well to read the sections which are contrasted with it. As a model to show how the keys are used, let us identify, first, a male adult Red-winged Blackbird-a black bird with a red and buff shoulder-patch. Turning to the key to the family Icteridæ, or Blackbirds, Orioles, etc., we read: "I. With yellow or orange in the under parts. "II. Under parts black, with or without metallic reflections. "III. Under parts grayish, slate color, chestnut, or buffy. "IV. Under parts black and white, or black tipped and margined with rusty."

Our bird has the under parts entirely black, so it evidently belongs in Section II. Under this section we read: "A. Outer tail-feather 0.75 or more shorter than middle ones; bill 1.00 or more in length." Our bird has all the tail-feathers of nearly equal length, the bill less than an inch long. It can not therefore belong in A, so we go to B and read: "Outer tail-feather little if any shorter than middle ones; bill less than 1.00 in length." There is no other section, and we conclude that our bird belongs here. Now we find a, b, c, d, each one placed directly beneath the other, and each one leading to the name of a species. This means that the statement following these letters refers to some mark or character by which one of these species may be known from the other, and that we should read them all. First comes "a. Entire plumage bluish black." That will not do. Second, "b. A red and buff shoulder-patch." Evidently this refers to our bird, but we confirm our belief by glancing at c and d, neither of which can apply to our specimen; we decide, therefore, that it is a Red-winged Blackbird, and turning to the extended description of Agelaius phœniceus verify our identification. USE OF THE KEYS.

Now let us take a somewhat less simple case-a male English Sparrow. This bird, you will doubtless remember, has a black patch on the throat and breast, a slate-colored crown, chestnut marks on the sides of the head, and a streaked back. Turning to the key to the family Fringillida, or Finches, Sparrows, etc., we read first the headings to the main divisions which, in the larger families, are placed at the beginning of the key in order that they may be more readily compared. "I. Under parts with red. "II. Under parts with no red, and without distinct streaks; throat or breast sometimes with a patch or spot. "III. Under parts without red, and with numerous streaks." Our bird undoubtedly belongs in Section II. Under this section we read first: "1. Tail with white spots, bars, or patches." Our bird has no white in the tail, so we go to "2" and read: "Without large white spots or patches in the tail." There is no number 3, so we have no hesitation in placing our bird in Section "2." The first subsection here is "A. Back without distinct streaks." Our bird is unquestionably streaked, and we therefore go to "B. Back distinctly streaked." There is no Section C, and it follows that our bird belongs in "B." Under B we have "a. Bend of the wing yellow" and "b. Bend of the wing not yellow." Our bird has no yellow on the wing, and we therefore place it in subsection b. This subsection is subdivided into "b¹. Crown bright reddish brown," etc., "c¹. Crown streaked or spotted," etc., and "d¹. Crown mixed grayish brown and rufous, ashy, or slate-color, without black streaks." Evidently our bird belongs in the group headed d¹, which we find includes four species, d², d³, d4, and d5. After reading the characters assigned to each of these, we have no hesitation in deciding that those under d4 apply to our bird, and we prove our identification by turning to the description of Passer domesticus.

I have purposely taken a comparatively complicated case. If I have made it clear, you will have no further difficulty in using the keys, so far as their construction goes. It might be supposed, from this somewhat lengthy description, that the process required much time; but as you become familiar with the use of the keys it should never take you more than five minutes to identify a bird with them.