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.
LIFE HISTORIES OF NORTH AMERICAN BIRDS
The Editor of The Condor:
Realizing that no one man can know all there is to know about all the birds and that the completeness of the Life Histories of North American Birds depends on the cooperation which the author receives from others, I wish to make this report of progress and appeal to your readers for contributions, trusting that you will find the space to publish it at an early date.
Two volumes have been published and the third, containing the Petrels and Pelicans and their allies, is printed and should soon be out. The manuscript for the fourth volume, containing the Ducks, up to and including the Ring-necked Duck, is now in Washington in finished form and ready. for publication. It is not too late to add to this, when I correct the galley proof, any notes of importance on habits or distribution, and not too late to substitute any particularly fine photographs for those that I have already selected.
I am now at work on the fifth volume, which will contain the remainder of the Ducks and the Geese and Swans. I expect to finish this during the winter and send it to the publishers in the spring. The life histories are practically all written, subject to revision, but the photographs have not been selected.
I have no notes on the courtship of the American and White-winged Scoters or of any of the Geese, except the Canada, or on any of the Swans or Tree Ducks. I have no nesting photographs of Harlequin Duck, Barrow Golden-eye, any Geese except White-fronted and Canada, any Swans, or any Tree Ducks. I should be glad to receive contributions of notes or photographs to fill in any of these gaps. Or I should be glad to correspond with anyone who has anything else to offer. I am, of course,
