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Mammals

Photo of Badger "Most important in becoming a nature detective is for you to learn to think like an animal, more specifically, like a wild mammal!" (A Field Guide to Mammal Tracking in North America, James Halfpenny,1986).

MooseMore than 40 mammal species are present on the refuge. Some of the more common species include white-tailed deer, yellow-bellied marmot, yellow-pine chipmunk, northern pocket gopher, meadow vole, porcupine, striped skunk, muskrat, American beaver, mink, and raccoon. Though not readily observable, there are eleven bat species found on the refuge (Refuge species list), all of which depend on the gallery forest for various stages of their life cycles. Of these 11 species, 3 of them are State species of concern including Townsend’s big-eared bat, hoary bat, and fringed myotis (Table 7 and Table 8).

Bat Houses at White BarnFinding and observing mammals on or off the Refuge is difficult because there is a lot less dynamic/timely information, compared to birding, to go on. Montana Field Guides-Mammals (official State website) will provide you with good information on which to build. One should become thoroughly familiar with identification, behaviors and ecological requirements of local species before going on a finding mission or field trip. Be prepared for brief looks using either binoculars or camera. Many times the best you may come up with are tracks/sign. A good strategy would employ a temporary "blind" (as simple as sitting still in one spot) and much patience in favored habitats...let them come to you instead of stalking. Of course, the ends don't always justify the means...be mindful of trampling or disturbing any vegetation, stay on trails.

A small mammal inventory (unpublished-on file) was done during June through August 1987 by Denver Holt (temporary Biological Aid) in five Otter Tracksdifferent habitat types. Forty-four mammals of five species were captured and identified over 900 trap-nights. Most common species was meadow vole (Microtus pennslyvanicus). Other species collected included: masked shrew (Sorex cinereus), vagrant shrew (Sorex vagrans), montane shrew (Sorex monticolus), and deer mouse (Peromyscus maniculatus). Darin Newton, University of Montana undergraduate, also did a small mammal survey (unpublished-on file) of the Refuge in 2008. Six species were captured in an 11 week period in four habitat types (forest, marsh, irrigation ditch and grassland) using Sherman traps and transects. Meadow voles were again most common, 56% of the 851 captured individuals. Additional species caught beyond the Holt survey list included yellow-pine chipmunk (Tamias amoenus) and short-tailed weasel (Mustela erminea).

Yellow-bellied MarmotExtensive census data of the white-tailed deer (Odocoileus virginianus) population has been recorded in the Refuge Annual Narratives. Like all mammal species there is an ebb/flow to population numbers. Refuge management wrote in 1987: "Mild winters during the past four years, an excellent food source, high reproduction and low harvest have perpetuated conditions for herd expansion. Conditions are ideal for a catastrophic die off due to harsh winter conditions or disease. Total habitat available to deer on the refuge is 2100 acres. Peak number of deer censused in 1987 was 329; yielding 1 deer/6.4 acres. Woody vegetation has suffered substantially from the surplus animals as evidenced by a browse line throughout most of the refuge." More detailed information on white-tailed deer is on our hunting webpage.
Last Updated: Nov 21, 2014
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