Gustav Kohn, New Orleans, La. T. McIlwraith, Hamilton, Ont. E. A. Mearns, M.D., Fort Snelling, Minn. Austin F. Park, Troy, N. Y.. J. T. Park, Warner, Tenn. Princeton College, Princeton, N. J. G. H. Ragsdale, Gainesville, Texas. W. C. Rives, M.D., New York City.. B. H. Warren, M.D., West Chester, Penn. Total... Article II.-THE NORTH AMERICAN SPECIES OF THE GENUS COLAPTES, CONSIDERED WITH SPECIAL REFERENCE TO THE RELATIONSHIPS OF C. AURATUS AND C. CAFER. By J. A. ALLEN. It has been known for more than thirty years that at certain points where the habitats of Colaptes auratus and C. cafer adjoin birds occur presenting the characters of the two species combined in the most heterogeneous manner, to account for which various hypotheses have been advanced. In order to arrive at the facts of the case, and to reach if possible a solution of the problem, I solicited, some months since, the loan of material for the prosecution of the investigation here detailed. Through the kindness of my fellow-workers, I have been able to bring together 785 specimens of the genus Colaptes, representing all of the North American and West Indian forms of the genus. These include nearly all of the available specimens in the leading public and private museums of this country, so far as they were considered especially desirable in the present connection.' I am especially under obligations to Mr. Robert Ridgway, Curator of Birds in the U. S. National Museum, for securing for me the use of the specimens under his charge, and to Mr. William Brewster for the loan of one of the most extensive and valuable series of these birds extant. Captain Platte M. Thorne, 22d Inft., U. S. A., sent a series of unusual interest from Colorado and Montana, which he has kindly presented to this Museum. Valuable specimens have also been presented by Mr. L. Belding, of Gridley, Cal., and Mr. R. T. Lawrence, of Olympia, Wash. To various other ornithologists I am under deep obligations for the generous loan of specimens, to each of whom I tender my sincere thanks for their kind coöperation. The subjoined schedule indicates the source and amount of the material on which the present paper is based, arranged alphabetically under the names of con The series of C. auratus from eastern North America might have been greatly extended had it been deemed necessary. tributors. The number of specimens received from any single source does not necessarily justly represent the relative value of the contribution, since some of the smaller lots often contain specimens of the highest interest, either on account of the localities represented or from the peculiar character of the specimens themselves. Charles F. Batchelder, Cambridge, Mass. 6 specimens. Lyman Belding, Gridley, Cal. 5 specimens. Capt. Charles E. Bendire, U. S. A., Washington, D. C. 2 specimens. Frank M. Chapman, New York City. 9 specimens. Charles B. Cory, Boston, Mass. 3 specimens (Colaptes gundlachi). B. T. Gault, Glen Ellyn, Ill. 3 specimens. E. W. Hasbrouck, Washington, D. C. 5 specimens. Gustave Kohn, New Orleans, La. 8 specimens. R. T. Lawrence, Olympia, Wash. 5 specimens. Prof. John Macoun, Canadian Geological Survey, Ottawa, Can. Dr. Edgar A. Mearns, U. S. A., Fort Snelling, Minn. 15 specimens. George B. Sennett, New York City. 22 specimens. Ernest E. Thompson, Toronto, Can. 2 specimens. Capt. P. M. Thorne, 22d Infantry, U. S. A., Fort Keogh, Mont. American Museum of Natural History, 178 specimens. Princeton College, 38 specimens. U. S. Department of Agriculture (through Dr. C. Hart Merriam), U. S. National Museum (through Robert Ridgway), 208 specimens. The following statement indicates, in a general way, the geographical sources of the material used. Idaho, I specimen. Lower California, 72 specimens. Maine, 4 specimens. Maryland, 10 specimens. Massachusetts, 16 specimens. Mexico (southern parts), 10 specimens. Michigan, 4 specimens. Minnesota, 15 specimens. Mississippi, 2 specimens. New Brunswick, 3 specimens. New Hampshire, 2 specimens. North Carolina, 12 specimens. Oregon, 7 specimens. Pennsylvania, 10 specimens. Sonora, 6 specimens. In addition to the specimens examined, much information has been gathered from the literature of the subject, and some from unpublished sources, derived from correspondence, particularly in regard to Texas, California and Arizona. The large amount of material thus brought together has naturally been utilized incidentally for other purposes than that of its bearing on the relationship of C. auratus and C. cafer, since it afforded exceptionally favorable opportunities for studying the characters of the several forms in their first or nestling plumages, as well as in respect to seasonal, individual and geographical variation. Consequently, a few paragraphs are devoted in the present paper to each of these subjects. Mr. Frank M. Chapman, Assistant Curator in this department, has also further utilized this material as the basis of his paper On the ColorPattern of the Upper Tail-Coverts in Colaptes auratus,' recently published in this Bulletin.' I. THE RELATIONSHIPS OF Colaptes auratus AND C. cafer. In 1858 Professor Baird, in his Report on North American Birds, first called attention to the unique and since then notorious case of C. auratus and C. cafer (or C. mexicanus, as then designated), as presented by a large series of specimens from the region of the Upper Missouri and Yellowstone Rivers, in which the characters of the two birds were combined in a constantly varying and often asymmetrical manner. His material enabled him to present very fully the leading facts of the case, and led him to conclude that the state of affairs thus revealed pointed clearly to hybridization on a grand scale between the two species 1 Vol. III, No. 2, Art. XXI, pp. 311-314, Aug., 1891. in question, notwithstanding the startling nature of such an assumption. While he named the variously intermediate birds Colaptes hybridus, he distinctly stated that the name was not given in a specific sense, but merely for the convenient designation of the intermediate birds. Under this name they were currently known in literature for the next quarter of a century. For a time Professor Baird's explanation of the case was very generally accepted as probably correct, but later other hypotheses were suggested. Thus, in 1872, when the distribution of the so-called 'hybrids' was supposed to cover a much smaller area than the examination of the present available material shows to be the case, it was argued that the peculiar intergradation between these two forms might be due to the action of environment,' in accordance with certain well-established laws of geographic variation affecting many other species having a somewhat similar distribution. This suggestion met with sufficient favor to render for a time the question at least an open one." In 1877 it was suggested that these intermediate birds might be "remnants of a generalized form from which two incipient species' have become differentiated," and that "this 'hybrid' series is gradually losing its neutral character through the nearer approach, generation by generation, of its members to the characters of one or the other of the two specialized forms.' In 1884 it was suggested that the so-called hybrids, or birds of mixed character, may constitute "perhaps....a hybrid, and perhaps....a transitional form." " The most recent writer on the subject treats the intermediate birds as a "race," with the nomenclatural status of a species, under the name Colaptes ayresi, which is only an earlier name for Baird's C. hybridus. While admitting that this 'race' was "produced originally by the union of C. auratus and C. mexicanus" (=cafer), the suggestion is made that these intermediate birds may be, in some cases, a sign of reversion to a remote ancestral plumage.' 1 Cf. Allen, Bull. Mus. Comp. Zoöl., III, No. 6, 1872, pp. 118, 119. 2 Cf. Coues, Birds of the Northwest, 1874, p. 293. a Ridgway, Orn. 40th Parallel, 1877, p. 556. Coues, Key to N. Am. Bds., revised ed., 1884, p. 492. A name given by Audubon in 1843 to mixed birds from the Upper Missouri country. |