THE PRESENT STATUS OF THE SUBSPECIES
To the Editor of The Condor:
In these days when ornithological nomenclature and taxonomy seem to have become of more importance than the birds themselves, the primary or, indeed, the sole object of our system is not to be lost sight of. A scientific name, once it is bestowed, is after all only an assembly of two or three words so grouped as to convey an idea of the approximate perch height of the lucky or unlucky recipient in the genealogical tree; or, to put it differently, a statement of the evolutionary progress made by the particular group or individual in question, down to the year A. D. 1922, or whenever the baptism took place. Now, it seems to me that the fact that a certain horned lark's back, or a certain fox sparrow's bill is different from the backs or the bills of horned larks or fox sparrows occupying other areas is distinctly secondary to the fact that separate geographic situations have caused certain changes to take place. Unfortunately, our only way of expressing what has happened is in terms of millimeters or of color, or by some other equally unsatisfactory designation. These means of describing what changes have occurred are undoubtedly what have given most people a wrong conception of systematic work in general, and of the so-called "subspecific" races in particular. If the rank and file of bird students would put aside the idea that "microscopic" subdivisions of plastic species are made only for the purpose of bestowing new names, and think of the determined "subspecies" as admittedly short, but still definite steps along the evolutionary highway, not only would the whole science of ornithology be benefited by a new interest, but we would be spared much of the ranting about "hair splitting", in which well-meaning but misguided souls indulge from time to time. What constitutes a subspecies is just now a difficult question to answer. A composite opinion gained by personal conversation, and by perusal of current literature can be best expressed by, "Why is a hen?" Some would use only a binomial for every recognizable form, others want to reduce to subspecific status all species bearing close resemblances to one another, and still others champion two kinds of subspecies: Obviously, the adoption of any of these extremes would work much harm, if for no other reason than that the true genetic relationships between most forms would not properly be expressed by the terms employed.
Most conservative ornithologists advocate a middle course and believe that intergradation should be actually proven before reducing any form to subspecific status. But, what sort of intergradation? If we take into consideration all angles of the problem, what can we possibly accept save that of geographic continuity,—an actual blood relationship? To designate as varieties geographically isolated forms which have been completely segregated for thousands, perhaps tens of thousands of years from similar organisms found in another area (or even on another continent!) simply because overlapping characters are shown by a few individuals is not telling the true story of conditions which now exist. True, there was undoubtedly one common ancestor; but so, for example, was there for all the grebes, or for all the gulls. If intergradation of all present-day species of grebes, or between any two of them were to be established through fossil remains—and this is not an impossible hypothesis—then, to be consistent, we should have now to regard them as subspecies: Intergradation through individual variation is inviting too many chances for error. As Grinnell (Auk, vol. 37, 1921, p. 469) has pointed out, what assurance is there that young or subadults or even "sports" may not be used in attempting to prove the point?
The criteria of isolation for the use of the binomial and of actual blood fusion for use of the trinomial will, I believe, prove the ultimate ones to be adopted not only because they permit of more accuracy in allocation, but also because of the uniformity possible under their use.
Yours very truly,
Pasadena, California, July 14, 1922.