Part 2

A key is a short cut used to approximate identification without reading a great number of descriptions. The keys given here differ in no essential particular from those to be found in other systematic works on ornithology, but for the benefit of the beginner their use may be briefly explained.

Having in hand an unknown bird begin with the key to the Orders (p. 7), reading first the line beginning a1; if the specimen has the characters given after a1 then the bird belongs to the Order Pelecaniformes and another key is to be used which will be found under that order, (p. 200). If the characters on the line after a1 are not found in the specimen, then those given on the line a2 are to be examined and these the specimen must have, if no mistake has been made. The next choice is between b1 and b2 and so on until characters are found which agree with those of the specimen and at the same time lead to a word at the right printed in heavy face type; this is the name of the order to which the specimen belongs.

Having determined the order turn to the page where the order begins and use the key there which leads to the suborders or to the families, then find and use the keys to genera and species.

To illustrate the use of keys with a concrete example, suppose that we have a specimen of the common spoon-billed duck or shoveler, but know nothing of its affinities. Beginning with the key to orders we find:

"a1. Hind toe connected by a web to the inner toe." As this does not agree with our specimen we try:

"a2. Hind toe not connected by a web to the inner toe." Yes.

"b1. Nostrils tubular." No. "b2. Nostrils not tubular." Yes.

"c1. Cutting edges of bill more or less distinctly fringed or serrated, tip of bill rounded ... Anseriformes."

Yes, and our bird belongs in the order Anseriformes. By a similar procedure we find that our duck belongs in the subfamily Anatinæ (p. 185) and in the key to genera (p. 187) we find:

"a1. Bill not spatulate." "a2. Bill flattened, and spatulate ... Spatula."

As our duck has a flattened, spatulate bill we turn to the genus Spatula (p. 196) and as there is but one Philippine species in this genus we know that our bird is--

Spatula clypeata (Linnæus).

SHOVELER.

A MANUAL OF PHILIPPINE BIRDS.

By Richard C. McGregor.

Class AVES.

Oviparous, warm-blooded, amniotic vertebrates which have their anterior extremities transformed into wings. Metacarpus and fingers carrying feathers or quills. With an intertarsal joint. Not more than four toes of which the first is the hallux. (Gadow.)

Subclass CARINATÆ.

Sternum with a keel; scapulæ and coracoids fused forming an acute or a right angle; foramen ischiadicum present; distal six or seven vertebræ fused to form the pygostyle.

Orders.

a1. Hind toe connected by a web to the inner toe ... Pelecaniformes (p. 200) a2. Hind toe not connected by a web to the inner toe.

b1. Nostrils tubular.

c1. Bill strong and decidedly hooked at the tip ... Procellariiformes (p. 84) c2. Bill weak, very small, gape very wide ... Caprimulgi in Coraciiformes (p. 295)

b2. Nostrils not tubular.

c1. Cutting edges of bill more or less distinctly fringed or serrated, tip of bill rounded ... Anseriformes (p. 184) c2. Cutting edges of bill not fringed.

d1. Rectrices rudimentary; or if evident not prominent, being short, soft, and hidden by the upper coverts.

e1. Tarsus flat; toes lobed ... Colymbiformes (p. 82) e2. Tarsus normal; toes not lobed.

f1. Hind toe wanting ... Hemipodii (p. 17) f2. Hind toe present. ... Excalfactoria and Megapodius in Galliformes (p. 9)