EVALUATION OF INDICES OF ABUNDANCE FOR AN UNEXPLOITED BADGER POPULATION ERIC W. HEIN AND WILLIAM F. ANDELT Department of Fishery and Wildlife Biology, ColoradoState University, Fort Collins, CO 80523 Present address of EWH: Environmental Sciences Group, MS f495, Los Alamos National Laboratory,Los Alamos, NM 87545 ABSTRACT-We evaluated indices of relative abundance for NorthAmerican badgers (Taxidea taxus) on the RockyMountain Arsenal, Adams Co., Colorado by comparing scent-station visitations, spotlight surveys,headlight surveys,road mortality,and a trappingindex to a minimumdensity estimateof 0.27 badgers/km2. Live capture, although time and labor-intensive, provideda minimum relative density estimate and a trappingindex to relative abundance. We captured15 of 18 (83%) badgers during July and August 1990. Twelve of 21 (57%)captures of badgers were in traps scentedwith Carman's CanineCall, whichmayhavepotential forincreasing capture success. If badgers arecaptured to estimate relative density or a trapping index, we suggest standardizing lures and seasons, and reporting if badgers were targeted or captured incidentally. Although North American badgers (Taxidea taxus) are found across the western United States and Canada (Messick, 1987), badger populations have not been widely studied (Lindzey, 1971, 1982; Messick and Hornocker, 1981). Badgers can be agricultural pests that damage crops, prop- erty, and irrigation systems, and prey on domestic fowl (Minta and Marsh, 1988). Data on the rel- ative and absolute abundance of badgers is scarce (Messick, 1987) but would be helpful for mon- itoring population levels (Lindzey, 1982). Techniques to estimate badger densities are not well developed (Messick, 1987), although mark- recapture (Messick and Hornocker, 1981) and modified mark-resight methods (Minta and Mangel, 1989) have been applied to badger pop- ulations. Indices are generally less costly than absolute density estimates and are commonly used by resource managers to monitor population trends (Johnson and Pelton, 1981; Clark and Andrews, 1982). Suggested indices for monitoring badger populations have included scent-station surveys, spotlighting, road mortality (Messick, 1987) and captures/1,000 trap nights (Lindzey, 1971). Scent-stations have been used extensively to monitor relative abundance of mammals (Linhart and Knowlton, 1975; Johnson and Pelton, 1981; Conner et al., 1983; Drew et al., 1988). Scent- station indices for bobcats (Felis rufus), gray fox (Urocyon cinereoargenteus), opossums (Didelphis virginiana) (Conner et al., 1983), and raccoons (Procyon lotor; Conner et al., 1983; Nottingham et al., 1989) have been evaluated by comparing indices to density estimates. However, scent sta- tions and other indices of relative abundance have not been evaluated for badger populations. Thus, we evaluated the use of scent-stations, spotlight- ing, headlight surveys, road mortality, and num- ber of captures/1,000 trap nights as potential indices of badger abundance. MATERIALS ANDMETHODS-The Rocky Mountain Arsenal (RMA) comprises 70 km2 at the northern boundary of Stapleton International Airportin Com- merce City, Adams Co., Colorado. Averageelevation is 1,600 m with maximumtopographical relief of ap- proximately 60 m. Commonwildlife includes white- tailed deer (Odocoileus virginianus), mule deer (Odo- coileus hemionus), black-tailed prairie dogs (Cynomys ludovicianus), black-tailed jackrabbits (Lepus californi- cus), coyotes (Canis latrans), badgers, and black-billed magpies (Pica pica). A variety of grasses, forbs,and shrubsare foundon the RMA including cheatgrass (Bromustectorum), crested wheatgrass (Agropyron cristatum), blue grama (Bouteloua gracilis), perennial summercypress (Kochia americana), sand sagebrush (Artemesia filifolia), and rubber rabbitbrush (Chrysothamnusnauseosus). Trees, such as plains cottonwood (Populus sargentii), New SEPTEMBER 1995 THESOUTHWESTERN NATURALIST 40(3):288-292