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166 Vol. XVIII A NEW RUFFED GROUSE, FROM THE YUKON VALLEY By JOSEPH GRINNELL (Contribution from the University of California Museum of Vertebrate Zoology) OON AFTER the establishment of the California Museum of Vertebrate Zoology, in 1908, there came into its possession the C. L. Hall collection of birds from Alaska and Yukon Territory. Two papers have already been based upon these (see CONDOR, XI, 1909, pp. 202-207, and CONDOR XII, 1910, pp. 41-43), but even so, the possibilities of further systematic interest were not by any means exhausted. There were contained in the Hall collec- tions, among other things of note in this regard, a series of eleven Ruffed Grouse from the Yukon Valley, as now listed in the accompanying table' of measurements. These were from the beginning recognized as differing materially from Ruffed Grouse available from other parts of North America. But until recently no opportunity has been had of comparison with topotype specimens of the already known race umbelloides, under which name Alaskan Ruffed Grouse have always been listed in literature. The type-locality of Bonasa umbellus umbelloides (Douglas) is probably in Alberta, Canada, somewhere o? one of the sources of the Peace River, lati- tude 54 degrees (A. O. U. Check-list, 1910, p. 140). A few weeks ago I was privileged to examine seven skins of the Ruffed Grouse in the U.S. Biological Survey collection in Washington, from Edmonton, Alberta, and six in the U.S. National Museum from Henry House, Alberta. These may be considered near-topotypes of true umbello?des, and they were found to differ en masse in certain significant respects from Yukon birds, so that it now becomes feas- ible to give the latter a separate name. Bonasa umbellus yukonensis, new subspecies. YUKON RvrrEV GROUSE Type.--MMe adult, no. 4515, Mus. Vert. Zool.; Forty-mile (on Yukon River near Alaska boundary), Yukon Territory; November 5, 1899; collected by C. L. Hall; orig. no. 127. Diagnosis.---Largest and palest of the races of Bonasa umbellus; nearest like B. u. umbelloides, but general coloration of light-colored parts of plumage more ashy, and pattern of dark markings finer. Geographical Distribution.---As far as now known only the interior of Yukon Territory and Alaska. Occurs along the Yukon River valley down nearly to its mouth, as also in adjacent wooded areas west even into the Seward Peninsula (see Nelson, Rep. Natural History Coll. Alaska, 1887, p. 131). Remarks.---As with the other subspecies of the Ruffed Grouse, yukonensis shows two color phases. Three out of the eleven specimens at hand have pale rusty tails; but even in this "red" phase the race is distinguishable from the corresponding phase in the other subspecies by paler tone of coloration. Typical umbelloides is still a gray bird, but its grayness is more leaden, and its browns and blacks are deeper. The extreme fineness of the intricate pattern of barring and mottling on the plumage is in yukonensis an appreciable char- acter.