California Department of Fish and Wildlife

Bay Delta Region

Biological Resources

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Main Office
  7329 Silverado Trail
  Napa, CA 94558
  (707) 944-5500

Stockton Office
  2109 Arch Airport Rd
  Stockton, CA 95206
  (209) 234-3420

Acting Regional Manager:
Scott Wilson

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Stanislaus River Report


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Stanislaus River Basin and Calaveras River Water Use Program
Threatened and Endangered Species Report - March 1995
Bay Delta and Special Water Projects Division, CA Dept. of Fish and Game

3.4 MAMMALS

For this report the mammal group is split into two sections, Special Status Bats and Other Special Status Mammals. This is done to facilitate the differences between these two mammal groups and the study methods used. The mammals listed include all Federal and California state listed species as well as "Special Animals" as defined by the NDDB.

3.4.1 Special Status Bats

There are 23 bat species found in California. Four species have been confirmed as occurring along the Stanislaus River and up to a total of 12 are expected to be using this area. Ten species listed by the state of California and the Federal Governmentf can be found in northern California. Of these ten special-status bat species, three were observed, five are expected to occur, and one additional species may occur along the Stanislaus River:

  • Yuma myotis (Myotis yumanensis) a Federal Category 2 candidate for listing by the U.S. Fish and Wildlife Service as Threatened or Endangered;

  • long-eared myotis (Myotis evotis) a Federal Category 2 candidate for listing by the U.S. Fish and Wildlife Service as Threatened or Endangered;

  • fringed myotis (Myotis thysanodes) a Federal Category 2 candidate for listing by the U.S. Fish and Wildlife Service as Threatened or Endangered;

  • long-legged myotis (Myotis volans) a Federal Category 2 candidate for listing by the U.S. Fish and Wildlife Service as Threatened or Endangered;

  • small-footed myotis (Myotis ciliolabrum) a Federal Category 2 candidate for listing by the U.S. Fish and Wildlife Service as Threatened or Endangered;

  • spotted bat (Euderma maculatum) a Federal Category 2 candidate for listing by the U.S. Fish and Wildlife Service as Threatened or Endangered, and a California Department of Fish and Game "Species of Special Concern";

  • two subspecies of the big-eared bat: (Plecotus townsendii townsendii and Plecotus townsendii pallescens) a Federal Category 2 candidate for listing by the U.S. Fish and Wildlife Service as Threatened or Endangered, and a California Department of Fish and Game "Species of Special Concern";

  • pallid bat (Antrozous pallidus) a California Department of Fish and Game "Species of Special Concern"; and

  • western mastiff bat (Eumops perotis californicus) a Federal Category 2 candidate for listing by the U.S. Fish and Wildlife Service as Threatened or Endangered, and a California Department of Fish and Game "Species of Special Concern".

Prior to conducting any field work, the NDDB was queried for bat listings along the Stanislaus River and surrounding areas. No observations were reported, primarily due to the lack of previous surveys for bats in the area. Secondly, scientific literature was researched for all bat species that might exist in the project area. Finally, E. Pierson, Ph.D. and Bill Rainey, Ph.D were consulted for any known bat surveys along the Stanislaus River. At the time of communication no surveys had been conducted, but recently E. Pierson is reported to have surveyed the Oakdale area and recorded one Plecotus townsendii, subspecies unknown, and heard vocalizations of Eumops perotis (BioSystems 1994).