Distribution, natural history, and parasites of mammals of Cook County, Minnesota

Natural history, distributions, and parasites of mammals of Cook County, Minnesota, were studied from the summer of 1971 through the summer of 1973. The purposes of this research were twofold. First, to determine species composition and relative abundance of individual species present in the county today. These base-line data may be used to project both back in time and into the future to assess man s effects on the mammalian fauna of the area. Second, to develop a technique for analyzing similari­ties and differences between the parasite fauna of groups of hosts as a tool in systematic and ecological research. Data on the mammalian fauna of Cook County were obtained through field collecting, by examination of mammal specimens from the county in collections, from discussions with individuals familiar with the local mammalian fauna, and from the published literature. The present mammalian fauna of Cook County is composed of 48 species of verified occurrence. Eleven other species may be inhabitants of the county, but documentation of their occurrence there is lacking. Data presented for verified species includes localities of record, comments on abundance, reproduction, habitats, taxonomy, parasites, and pertinent literature. Known distributions and pertinent literature are presented for the eleven species of unverified occurrence. All mammalian species of verified occurrence have been reported from the state previously; however, the records of Sorex arcticus, Sorex palustris, Condylura cristata, Myotis keenii, Lasionycteris noctivagans, Lasiurus borealis, Microtus chrotorrhinus, Synaptomys cooperi, Napaeozapus insignis, Procyon lotor, Martes americana, Martes pennanti, and Lynx canadensis especially aid in our understanding of their distribution and natural history. Ectoparasites representing three widespread groups of parasitic arthropods (Anoplura, Siphonaptera, Acari) were found parasitizing 20 species of small mammals in the county. Host–parasite records are presented for 23 species of fleas, 11 species of mites, 6 species of sucking lice, and 3 species of ticks. New host records are reported for six species of mites and one species of tick. New state records are recorded for seven species of mites and five species of fleas. A technique was developed which produced an artificial classification of the mammalian fauna based entirely on the similarity of the ectoparasitic fauna between species. Similarity was calculated using Sorensen's similarity coefficient. An agglomerative clustering program utilizing within-group sums of squares was used to produce a two dimensional phenogram of the hosts. This clustering technique may prove to be of value in comparisons of similarity and difference between hosts or other communities. Man's effect on the mammalian fauna has been to increase species diversity. The recent additions to the mammalian fauna are of deciduous forest affinity, are widespread in North America, or are introduced. Two species of coniferous forest affinity, Gulo gulo and Rangifer tarandus, have been extirpated recently from the county. It is hypothesized that most future additions to the mammalian fauna of Cook County, Minnesota, will be of deciduous forest, widespread, or of the introduced category of faunal affinity