C. CLASSIFICATION ACCORDING TO COLOUR
[I. Black.] [II. Blue.] [III. Brown.] [IV. Coffee or fawn colour.] [V. Green.] [VI. Grey.] [VII. Pink.] [VIII. Red.] [IX. White.] [X. Yellow.] [XI. Birds of many colours.]
Colour affords the easiest means of identifying the great majority of birds, but in many cases the colours displayed, although conspicuous and easily recognised, are not of a nature to admit of strict classification. Take, for example, the blues—various species display almost every known shade from slaty grey to turquoise, from purple to ultramarine and indigo. To attempt to distinguish in the lists between the many shades of blue would have led to inevitable confusion. I have, therefore, divided my blues into bright blue, dark blue, and slaty blue. My method is probably inartistic, but it will, I hope, facilitate the task of identification.
Again, it is no easy matter to draw the line between greyish and brownish birds, hence I have included some species under both heads. The reader should bear in mind that, while nothing is easier than to identify some birds by their colour, in the case of others colour is at the best a rough guide—one, but only one, of the clues which have to be followed up before the identity of the species can be established. In the case of Raptorial birds colour is of very little assistance, since the great majority of them are of the same colour, moreover, individuals vary greatly in colouration at different stages of their existence.