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 '7 THE CONDOR VOL. IX Another group of questions which ornithologists are in an especially favorable position to tackle is that of correlated characters and variations. Much could be done here without resort to breeding experiments. Observation coupled with atatomy and embryology could go a long. way. Perhaps the most practical and in- teresting single question is that of whether or not the superficial characters ordina- rily used for differentiating species are not associated, even if not actually cor- related with other more deeply seated structural characters. I am not thinking about anatomical features that might serve as reliable tests of affinity, and hence as bases of more natural classifications. Of course I do not neglect the labors of such anatomists as Huxley, Fuerbringer, Shufeldt, Lucas and others in this field. Tax~ onomic trials with anatomical data have been carried far enough to justify, proba- bly, the opinion of Newton and Gadow that "it is hopeless to attempt to arrive at a natural classification of Birds by a mechanical arrangement of even a great num- ber of alleged leading characters." What I have in mind is quite a differeut matter. It is this: Given two or more species of a genus well defined by characters generally used in ornithology, what other differentiating characters, if any, would a thorogoing examination of the whole animal discover ? I am quite sure that we must sooner or later, see that characterizing a species just far enough to place it in an artificial system of classification, is a very differ- ent matter from defining it thru and thru: that is, in such a way that nothing whatever truly distinctive about it shall have been left out. This is the sort of definition we shall demand when once we get red-hot after the problem of what a species really is. An individual bird consists of all there is of it from the time in- cubation begins until it dies. Isn't that so? If not, what segment of the life cycle does not belong to the individual? I am sure no bird man, thoroly imbued with what I take to be the distinctive spirit of ornithology, has the least desire to thtts fragment a bird's life. Well, if the real bird is the whole life of the bird, then for its whole life it is a member of its particular species; and if at ao' period'of its life it has characters that are different from those possessed by any other species whatever, these must be specific characters and would surely be noted in a full description of the species. This, of course, means practically that the egg, not merely the e.-s]tell, the sperm, the embryo at all its stages, the fledgling, the adult bird in all its phases of moulting, with all its habits and songs, would have to be attended to in a thoro- going definition of the species. Ornithologists have as a whole done better in this regard than other zoologists, and that is just 'the reason why they should do still more--vastlymore--in the same direction. "To him that hath shall be given." The complement of the old truth is more to the point here: "Of him that hath accomplished shall more be expected." One might easily designate other places wherein ornithology may be expected to shine in the new era of exacter, broader observation, and more critical testing of hypotheses and definitions into which biology is now fairly entered. The hard task, for instance, of establishing a more exact and trustworthy scale of values for characters, ornithology should contribute to largely. What department of biology except possibly entomology, is in better position to handle color from this point of view? It vould be easy to designate other places iu evolutionary theory at which ornithology might work with peculiar efficacy; but these are enough for a liberal program.