1997-06-13_REPORT - M1981302 (15)

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Livetrapping.—At each study site, livetraps were run for four days without prebaiting. (Sometimes dates of trapping were interrupted by weather conditions that were judged to be hazardous to livetrapped animals.) On each tract, six separate transacts were run, each with 50 large (7 x 9 x 23 cm) Sherman' livetraps (a mix of folding and folding styles) baited with sweet feed mixture (Purina "Omolene"® or an analogous product). In total, 300 traps were set each evening for four days, a total of 1200 trap-nights per locality, except that—due to vandalism—Transect F on the Gebhard Parcel was abandoned. Therefore (ignoring the unknown number of traps that might have been tripped by wind, rain, etc.), some 17,800 trapnights were sampled across the 15 weeks of trapping planned with and funded by the U. S. Fish & Wildlife Service. Traps were opened at dusk and checked soon after dawn daily. Note that one area, Tracy Collins, was sampled twice. This is an area where earlier workers (Dawson, 1989) had captured a meadow jumping mouse. It was sampled early in the season, during a period of generally unsettled, cold and wet weather and heavy runoff. On the chance that weather had interfered with mouse activity the area was resampled. Also, given the capture of several meadow jumping mice at the VanVleet site in Week 2, the field crew returned to that site for Week 15, to confirm the continued presence and activity of the mice. Funding from the US Fish & Wildlife Service ended on 15 September. However, the City of Boulder Open Space and Real Estate Department decided to fund continued trapping of small mammals at one known locality of Z hudsonius, the VanVleet Parcel, intending to determine the time of immergence of the mice into hibernation. The general protocol was that each week (beginning 18 September), 300 traps would be set for up to four successive nights. In the event of capture of a meadow jumping mouse, demonstrating above-ground activity of the mice, then trapping for that week would be curtailed, to begin again the following week. With that procedure, date of immergence could be bracketed within a 1-week period. Under the foregoing procedure, 300 trapnights were run 18 September, 600 trapnights were run 27-28 September, 300 trapnights were run 4 October, and 300 trapnights were run 10 October. Then, to maximize the likelihood of trapping a meadow jumping mouse if the animals still were active above ground, traps were shifted for the period 17-21 October, when 300 trapnights were run for each of three nights (17, 19, 21 October), a total of 900 trapnights. (Data from that final trapping are not directly comparable with those from other trapping on the VanVleet Parcel and therefore are not reported in various tables in this report.) In summary, a total of 20,200 trapnights were run from May through October 1996. In the tables throughout this report, genera of small mammals are listed in conventional phylogenetic order and species are listed alphabetically within genera (Fitzgerald et al., 1994). Research was conducted under Scientific Collecting License #950024 issued by the Colorado Division of Wildlife. 9