1997-06-13_REPORT - M1981302 - Laserfiche WebLink

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Zapus hudsonius prebki Interim Survey Guidelines, May 27, 1997 8 odor of disinfectants, detergents, etc. Double trapping transects are recommended to inventory for Preble's. The traps should be set in two parallel lines of trap stations (I trap per station). Trap stations will be 5 m apart; the parallel transects will be 10 m apart unless extent of habitat, terrain topography, or stream hydrology do not allow. Actual orientation of transects will depend upon local topography, drainage, etc. Survey methodology may be adapted to best cover individual project sites. The developers of these guidelines believe that the equivalent of 400 - 1000 trap nights in suitable habitat should be adequate to determine presence or absence. As a general standard, 750 trap nights appears appropriate. In cases of limited acreage of potential Preble's habitat, reducing trapping effort to as little as 400 trap nights may be reasonable. Greater effort should be expended in larger arras of suitable habitat and at or near areas of historical occurrence (i.e., more trap nights, multiple trapping efforts during the season, and/or trapping in multiple locations within the suitable habitat). Locations of transects will be recorded on field data sheets (see attached example) and identified on aerial photographs or 71h quad maps. Locations will be recorded at least to a precision of 'k 'k of a section, township, range (i.e., a 40-acre tract), and in UTM coordinates to the nearest 50 meters. In case of windy conditions or large number of trap-tampering predators (i.e., raccoons, foxes, coyotes, etc.), traps will be secured to the ground with hoops of heavy-gauge malleable wire, stakes, or with other materials that can effectively secure/immobilize the traps. A small ((g� 1") ball of polyester quilt or wool (fleece) will be placed in each trap as nesting/bedding material. Cotton should not be used as it absorbs moisture and loses heat readily and can contribute to thermal shock of captive animals. To minimize trap-raiding by larger mammals (e.g., skunks, raccoons) traps should not be pre- baited. The baiting materials will be rolled oats, rolled oats and peanut butter, or "omolene" (sweet oats). Some researchers in Wyoming have successfully trapped mice using a combination of bacon grease, peanut butter, and rolled oats. No other baiting materials or mixtures will be used without approval from the CDOW or WGFD, and the Service. In setting out single trap lines or a series of parallel lines, it might be assumed that most of the individual animals and species within easy travel range of the traps will be equally susceptible to being caught. This is not true since some species (and probably some individuals) will be attracted to this bait much more quickly than others. While deer mice may be drawn from a considerable distance by the smell of the bait, some other species may be only mildly attracted. Therefore, non-target species may occupy a number of traps, excluding more secretive, less numerous, or more trap-shy species, including Preble's, from these traps. For this reason, at sites where a high proportion of traps are being occupied by species other than Preble's, additional trap nights should be considered to offset this reduced availability.