Mar., 1918 83 



THE SUBSPECIES OF THE OREGON JAY 



By H. S. SWARTH 

 (Contribution from the Museum of Vertebrate Zoology of the University of California) 



IN A RECENT paper on the races of Perisoreus obscurus*, the author, Dr. 

 Harry C. Oberholser, arrives at certain conclusions, interesting in themselves 

 but resulting in a systematic treatment of the species which it seems to the 

 present writer contains a large element of error. Briefly, the important features 

 of the paper are the description of a new subspecies, Perisoreus obscurus raih- 

 buni, from the Olympic Mountains and Puget Sound regions, the restriction of 

 P. o. obscurus to the coast region between central Washington and Humboldt 

 Bay, California, and the inclusion of Vancouver Island in the range of P. o. 

 griseus. 



In plotting a map of the general range of Perisoreus obscurus (roughly, as 

 needs be, considering the few definite stations from which the species has been 

 recorded) it is interesting to note the positions of the type localities of the three 

 described subspecies, obscurus from Shoahvater Bay, Pacific County, Washing- 

 ton, griseus from Keechelus Lake, Kittitas County, Washington, and rathbuni 

 from Lake Crescent, Clallam County, Washington. These three stations are 

 about equidistant apart, a little over a hundred miles distant each from each, 

 forming a small triangle about at the center of the range of the species. As an 

 unfortunate result it follows that however the species obscurus may be divided 

 into distinguishable races the individuals selected as types have been taken at 

 points wmere intergradation of characters might be expected to occur, and not 

 from regions where extremes of differentiation are found. 



Perisoreus obscurus rathbuni is described as differing from P. o. obscurus 

 in darker coloration and somewhat greater size. As regards color it may be ob- 

 served that there are several bird races of the northwest coast that appear to at- 

 tain to the darkest extremes of shades on the mainland of the Puget Sound re- 

 gion. In the Bewick Wren {Thryomanes bewicki) for example, specimens from 

 this section are appreciably darker than those from Vancouver Island to the 

 northward or from the mainland to the southward. (See Swarth, Proc Calif. 

 Acad. Sci., 4th ser., vol. 6, 1916, p. 65.) In the Spotted Towhee (Pipilo macula- 

 tus), although there is no extensive series at hand from the mainland about 

 Puget Sound, still, an adult male from Seattle is darker colored than any Van- 

 couver Island bird. Then, as to the size differences shown by the Oregon Jays 

 of the several regions, it will be noted that P. o. rathbuni is somewhat larger 

 than P. o. obscurus, to the southward. Typical obscurus, again, is larger than 

 birds still farther to the southward, as shown by a large series from the Hum- 

 boldt Bay region, California, here available. 



Thus it is seen that from the southern extreme of the species at Humboldt 

 Bay, northward to Puget Sound, there is gradual increase in size and intensified 

 darkness of color. It is just such a case as that concerning the Wren-tit, pre- 

 sented and commented upon with such clearness some years ago by Osgood, in 

 The Condor (vol. 3, 1901, p. 50). The diagrams illustrating the points made in 

 that paper might well be studied in connection with the questions involved in the 



♦Description of a new subspecies of Perisoreus obscurus. By Harry C. Oberholser. 

 Pioc. Biol. Soc. Wash., vol. 30, Dec. 1, 1917, pp. 1S5-188. 



