Amphibians and Reptiles of the Rogue River Basin, Oregon

Abstract

The region drained by the Rogue River includes parts of Jackson, Josephine, and Curry counties, in southwestern Oregon, and of Siskiyou and Del Norte counties in northwestern California. Roughly, it is bounded on the east, south, and north by the crests of the Cascade, Siskiyou, and Umpqua mountains. It comprises an irregular area having a maximum breadth of about 120 miles west to east and of perhaps half that distance from north to south. This area is possessed of varied climate and rough topography. The coastal belt supports dense forests of Douglas fir, coast hemlock, tan oak, California laurel, and Port Orford cedar. To the mouth of the Illinois River at Agness, for more than 40 miles the Rogue River runs through a deep gorge. The region of this gorge, and its counterparts on the tributary Illinois and Applegate rivers, is dry and rugged; Garry and golden oaks, manzanita, and buck-brush (Ceanothus cuneatus) are some of the plants most characteristic of the steeper slopes. A few miles west from Grants Pass the head of the main gorge opens out into a valley, most of which is under cultivation. The foothills around the valley include areas of dry, open grassland, as also areas of chaparral, oak, and madrone. At high altitudes this scrub type of forest grades into yellow pine and Douglas fir. Yet higher, discontinuou's belts of Canadian and Hudsonian life zones partly surround the valley, forming more or less effective barriers to some species of amphibians and reptiles. During the 25 years of my residence in this region, I gained general familiarity with its fauna. However, no specimens were preserved and no field notes were written until the summer of 1932. In the summers of 1934 and 1935 I made collections and notes on nearly all the species, and trips were made to parts of the area not previously visited, notably along the lower course of Rogue River. Most of the specimens collected, representing all the species except Batrachoseps attenuatus and Contia tenuis have been deposited in the Museum of Vertebrate Zoology, University of California. Numbers given are as of the herpetological catalogue in the Museum, unless otherwise indicated. From time to time I have kept under observation in large outdoor cages many individuals of most of the species here discussed. In the following accounts it is my aim to summarize the geographic, zonal, and ecologic distribution of each form found within the area, and to include observations on its natural history. Specific localities are mentioned for rare species represented by few localities; but for common species represented by many records, these have been summarized in general statements. All localities mentioned may be found on the U. S. Geological Survey topographic maps or on national forest maps. 634