Laserfiche WebLink
raptured more than 1.5 months later than the last date of adult capture(last day of capture:October <br /> 27), and probably would have been captured at even later dates except that field exercises were <br /> terminated. The weather during this period in September/October was variable,with wanner than <br /> average temperatures but also cold,wet periods and one significant snowfall. The mice would <br /> disappear during the colder periods but then wild reappear on trapfnes as the weather warmed. <br /> During this earty fall fattening period the juvenile mice began to dearly develop a prominent dark, <br /> dorsal band. <br /> These dates of immergence are in accord with more eastern and midwestem subspecies of Zapus <br /> hudsomivs(Quimby, 1951 and Whitaker. 1963). Quimby indicated that adults captured in Mimesola <br /> after September 20 were either subadills or adults not yet faL <br /> Bruce A Wunder(personal communication)has shown that attuits continued to fatten until body fat <br /> composition was approximately 2M. and then went into hibernation. He tracked a meadow jumping <br /> mouse fitted with a radio transmitter to the only hibernaarlum farad yet in Colorado,at Rocky Flats, <br /> on October 11. 1995. The site was about 9 meters in elevation above the bed of Walnut Creek(at <br /> 1946 m). It had a thick cover of Prunus vkonhm Syrnpborkarpos occidentalis and Toxicodendron <br /> rydbergiK and the mouse was found in a leaf titer nest 30 cm beneath the ground Sod temperature <br /> at 30 cm was 9.50 C and texture was a silt barn to 30 cm, becoming a sandy loam below this. The <br /> hibemaculum was on a north-facing slope to was probaby a snow accumulation area,staying cod <br /> in the spring. <br /> Hibemacula have also been boated for eastern and midwestem Zaps hudsomus in a variety of <br /> conditions including sand banks, compacted wood ash,woodchuck burrows,dikes,and tilled soil. <br /> Leaf nests are often reported in the hibemacvla. The landscape position of the hibemacu a relative <br /> to habitat in the active period is often not reported;this may be an important factor for meadow <br /> jumping mice In Colorado and Wyoming. Hillsides that are upland from riparian areas are often <br /> downplayed or ignored as habitat,and if the Rocky Flats rase is typical,this could be a serious <br /> omnism . More hibernaaia need to be located so that the entire range of habitat requirements an <br /> be acaMety described. <br /> The earliest recorded emergence date in Colorado is May 5.from Rocky Fiats. The ix5vidiA <br /> aphred was an adult male;other early records from this site idiaW that males dominate the <br /> ap4ue until mid-May(PTI, 1998). By late NW captives are approomnately equally distributed <br /> between adult males and females. This is siniar to findings by Quimby(1951)and Whitaker(1983); <br /> mat Zspurs emerged first,followed by females an average of 15 days later. Quimby indicated that <br /> emergence was not related concisey to a partialar day,but was more dependent on prevailing <br /> conditions;he accurately predicted emergence dates from local pherobgical phenomena. <br /> In summary.tittle is known of kmmergenoelemergena activity and hibemacula requirements. The <br /> few Colorado data adicate that <br /> • The active period for the meadow Jumping mouse in C;obradoMyoming shadd be considered <br /> May 10ro gh October 31. Although perlods of are not the best times <br /> for canduetig preser o Wabsena su 4eys,mice should be considered active at these times. <br /> Ftrtmemmoro, tines may be critial in the mane dfe cycle because of <br /> springbiesdir9activity(special rdrsery areas and fataiin8 regcrements in the face <br /> • The only hibemaculum boated in Colorado was in an upland position relative to habitat in the <br /> major active period. We do not know how representative this case a,but t upland sides are <br /> needed for this function, lt can have major iepecb an the arrant understanding of required <br /> habitat The paucity of nfomneton an required habitat for hibemacula is probably the most <br /> significant data gap in understanding the meadow jumping mouse life cycle. <br /> 5 <br />