- This paper lists, and gives individual accounts of, those Oregon mammals that at some time have been referred to as being of a status other than common. Although rare and endangered wildlife species were listed on a national level in the United States, the
large areas of land included in the range of some species often allow population changes in local areas to go undetected. Several authorities have recognized the need for local and regional studies to determine the status of wildlife species. No comprehensive study of the mammals of Oregon has been conducted since 1936. I reviewed the available literature concerning Oregon mammals and compiled a working list of species. All species that were referred to as "uncommon, rare, or scarce" were included for additional study. Specimens deposited in museum and personal collections
were examined and the date and location of collection of specimens of each species under investigation were recorded. Collection sites of specimens were depicted on maps. Mammalogists, game biologists, naturalists, trappers, and outdoorsmen having knowledge of Oregon mammals were interviewed, and asked to comment on the current distribution and abundance of the species with which they were familiar. Information from all sources was used to develop criteria for placing each species into one of the following categories: recently extirpated, endangered, rare, status undetermined, or not presently rare or endangered. Mammals were classified as follows: Mammals recently
extirpated from Oregon; grizzly bear (Ursus arctos), wolf (Canis lupus), bison (Bison bison). Endangered mammals in Oregon; Richardson ground squirrel (Spermophilus richardsoni), kit fox (Vulpes macrotis), sea otter (Enhydra lutris), wolverine (Gulo
luscus), lynx (Lynx canadensis), Columbian white-tailed deer (Odocoileus virginianus leucurus). Rare mammals in Oregon; Maiheur shrew (Sorex preblei), Merriam shrew (Sorex merriami), Ashland shrew (Sorex trigonirostris), Brazilian free-tailed bat (Tadarida brasiliensis), white-footed vole (Arborimus (Phenacomys) albipes), ringtail (Bassariscus astutus), fisher (Martes pennanti), northern elephant seal (Mirounga angustirostris), bighorn sheep (Ovis canadensis). Mammals of undetermined status in Oregon; fringed myotis (Myotis thysanodes), western pipistrelle (Pipistrellus
hesperus), Washington ground squirrel (Spermophilus washingtoni), little pocket mouse (Perognathus longimembris). Mammals evaluated but not presently rare or endangered in Oregon; hoary bat (Lasiurus cinereus), white-tailed hare (Lepus townsendii), pigmy rabbit (Sylvilagus idahoensis), antelope ground squirrel (Ammospermophilus leucurus), Bottae pocket gopher (Thomomys bottae), dark kangaroo mouse (Microdipodops megacephalus), Heerman kangaroo rat (Dipodomys heermanni), heather vole (Phenacomys intermedius), red tree mouse (Arborimus (Phenacomys) longicaudus), California
meadow mouse (Microtus californicus), sagebrush vole (Lagurus curtatus), marten (Martes americana), badger (Taxidea taxus), river otter (Lutra canadensis), northern sea lion (Eumetopias jubata), California sea lion (Zalophus californicus), harbor seal (Phoca vitulina), mountain lion (Felis concolor), Idaho white-tailed deer (Odocoileus virginianus ochrourus). The necessary use of imprecise terms such as "very uncommon"
in defining categories of classification injected a degree of subjectivity into the proposed classification. However, it is believed that this study consolidated existing knowledge, and that it will provide a basis for future, more detailed studies which may reveal basic ecological requirements of rare and endangered forms of mammals in Oregon.