1997-06-13_REPORT - M1981302 (15)

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comparisons of pairs of days also were mostly significant; captures on day 3 were significantly greater than on day 2 (p = 0.044), and captures on day 4 were significantly greater than on day 3 (p = <0.001). This result would suggest that brief trapping periods (i. e., one or two nights) might not reveal the presence of meadow jumping mice on sites where they are present. Generally, reports by other workers of captures of Z hudsonius in the Boulder area lack the detail to permit comparison with our results. However, we note that the single meadow jumping mouse captured on the VanVleet Parcel in August 1992 was captured the second of three nights of trapping (with 100 traps per night) (Compton, 1992). Capture/Recapture and Movements.—This was a reconnaissance survey, intended to determine presence of meadow jumping mice on particular parcels. However, animals were marked (by fur-clipping) when captured and then released, and there were a few recaptures, allowing some preliminary insight into movements. We comment here only on captures of Z hudsonius. On the VanVleet parcel in May there were 11 captures of 11 individuals (no recaptures). In the second week of September (week 15, the final week of the contract survey), four individuals were captured in the VanVleet parcel. After the end of the USF&WS contract, three individuals were captured on 28 September, one on 4 October. One individual was taken on Transact F on 21 May and 28 September, at stations (L-1 and L-14) in the same line, 70 m apart. On the Gebhard Parcel, nine individuals were captured a total of 14 times on three different transects. One individual was captured four times on transect E, moving from station R21 to L22 (11.2 m, calculated as the diagonal connecting the stations to yield a minimal—i. e., conservative—estimate), to L23 (5 m) to L20 (15 m). Two other individuals were each captured twice on transect E, one moving from R15 to L21 (31.6) between consecutive nights, the other moving from R11 to R3 (40 m) between consecutive nights. Active.Period.—Given the large geographic extent of this reconnaissance study and the remarkably cold, wet spring, this study could not pinpoint the period of activity above ground. In particular, we have no reason to believe the animals were not emerged and active in April, although weather conditions did not permit our beginning field work that early. However, we quite deliberately tried to bracket the time of immergence into hibernation by trapping late into the season at a known locality. Earliest capture of a meadow jumping mouse was 16 May on the VanVleet Parcel. Latest capture was 4 October, also on the VanVleet Parcel, hence the minimum period that at least some individuals of the population were above ground in 1995 was 140 days. R. E. Stoecker captured a meadow jumping mouse on 10 October, in 1994 (ERO Resources, 1995). Habitat The general purpose of this section is to describe habitats on study sites and to compare sites with and without meadow jumping mice. Eventually, this should contribute to developing a comparative description of this mouse over its range in 14