48.

Southern Red-backed Vole

Myodes gapperi

French: Campagnol de Gapper / German: GapperRotelmaus / Spanish: Topillo rojo de Gapper

Other common names: Boreal Red-backed Vole, Gapper’s Red-backed Mouse, Gapper's Red-backed Vole, Revillagigedo Island Red-backed Vole

Taxonomy. Myodes gapperi Vigors, 1830, between York [= Toronto] and Lake Simcoe, Ontario, Canada.

Myodes gapper: might represent more than one species. Twenty-nine subspecies recognized.

Subspecies and Distribution.

M.g.gapperiVigors,1830—SEManitoba,SOntario,NMinnesota,andWisconsinEacrossGreatLakesregiontoEQuebec.

M.g.arizonensisCockrum&Fitch,1952— WhiteMts,CEArizona,USA.

M.g.athabascaePreble,1908—fromNEBritishColumbiaEtoWManitoba,Canada.

M.g.brevicaudusMerriam,1891—isolatedrangeinNEWyomingandCWSouthDakota,USA.

M.g.carolinensisMerriam,1888—SAppalachianMtsfromVirginiaStoextremeNGeorgia,USA.

M.g.cascadensisBooth,1945—CascadeRangeofCWashington,USA.

M. g. caurinus Bailey, 1898 — coastal British Columbia, Canada.

M.g.galeiMerriam,1890—fromextremeSAlberta,Canada,StoCUtah,USA.

M.g.gaspeanusR.M.Anderson,1943—GaspéPeninsulaofEQuebecandextremeNNewBrunswick,Canada.

M.g.gautiCockrum&Fitch,1952—fromSColoradoStoCNewMexico,USA.

M.g.hudsoniusR.M.Anderson,1940—SofHudsonBayinManitoba,Ontario,andQuebec,Canada.

M.g.idahoensisMerriam,1891—WOregon,Idaho,WMontana,andWWyoming,USA.

M.g.limitisBailey,1913—mountainsofCWNewMexico,USA.

M.g.loringiBailey,1897—SEAlberta,SSaskatchewan,andSManitoba,Canada,andNMontana,NorthDakota,extremeNSouthDakota,mostofMinnesota,andNCIowa,USA.

M.g.maurusKellogg,1939—smallrangeinEKentuckyandVirginia,USA.

M.g.nivariusBailey,1897—OlympicMtsofWashington,USA.

M.g.occidentalisMerriam,1890—extremeScoastalBritishColumbia,Canada,andNWcoastofWashington,USA.

M.g.ochraceusG.S.Miller,1894—PrinceEdwardI,NewBrunswick,andextremeSEQuebec,Canada,SalongtheAtlanticcoasttoMassachusetts,USA.

M.g.pallescensHall&Cockrum,1952—NovaScotia,Canada.

M.g.paludicolaDoutt,1941—NEOhioandNWPennsylvania,USA.

M.g.phaeusSwarth,1911—ScoastalSEAlaska,USA,toFortSimpson,CEBritishColumbia,Canada.

M.g.proteusBangs,1897—NEQuebecandLabrador,Canada.

M.g.rhoadsiiStone,1893—restrictedrangeinSENewYorkandadjacentNewJersey,USA.

M.g.rupicolaPoole,1949—knownonlyfromKittatinnyRidge,EPennsylvania,USA.

M.g.saturatusRhoads,1894—NBritishColumbia,Canada,StoNWashington,NIdaho,andNMontana,USA.

M.g.solusHall&Cockrum,1952—restrictedtoRevillagigedoI,SEAlaska,USA.

M.g.stikinensisHall&Cockrum,1952—NcoastalSEAlaska,USA,andWBritishColumbia,Canada.

M.g.ungavaBailey,1897—NQuebec,Canada.

M. g. wrangeli Bailey, 1897 — Sergief and Wrangell Is, SE Alaska, USA.

Descriptive notes. Head-body 100-114 mm, tail 30-44 mm, hindfoot 19-21 mm; weight 16-42 g. Dorsal pelage of Gapper’s Red-backed Vole has well-defined stripe and varies from bright red to dark rufous. Sides and belly are grayish, with tips of guard hairs on belly ranging from white to buff. Tail is short, thick, and bicolored, with bristly reddish or blackish hairs dorsally and lighter hairs below. Post-palatal bridge is usually complete, and M? and M, have more complex enamel patterns than those of the Western Red-backed Vole ( M. californicus).

Habitat. Mesic coniferous, deciduous, or mixed forests. Southern Red-backed Voles are most common in habitats with structural habitat complexity such as high density of rotting stumps, logs, or other downed debris, or exposed roots that can be used for nesting. Eastern forests and forest edges, woodlots, old fields with rock walls, and sedge meadows are suitable habitat. In the Midwest, mixed deciduous forest or coniferous forests are common habitat, and in western North America, forests of ponderosa pine ( Pinus ponderosa), Douglas fir ( Pseudotsuga menziesii), spruce ( Picea), hemlock (7suga, all Pinaceae), cedar ( Thuja, Cupressaceae), and other trees are used. Nearby mesic or ecotonal habitats with high vegetation structure also commonly support this species. At northern edge of the distribution, it occurs across vast boreal forests of Canada.

Food and Feeding. Southern Red-backed Voles frequently shift their diets to match food availabilities by feeding on plants (including nuts, seeds, berries, leaves, roots, and bark), fungi, arthropods, mosses, ferns, lichens, and other foods.

Breeding. Southern Red-backed Voles are promiscuous. Females are polyestrous and have postpartum estrus. They usually breed from March to late September. Litters have 2-8 young, with largerlitters found in high latitudes and high-elevation populations. Sexual maturity is reached at 2—4 months. Nests are 75-100 mm in diameter and lined with grass, leaves, moss, and sphagnum.

Activity patterns. Latitude and seasonality impact activity patterns of Southern Redbacked Voles. At high latitudes, some populations were active nocturnally in winter when nights were long but were more diurnal or crepuscular in summer when days are long. In other high-latitude populations, the opposite activity pattern was noted. More southern populations tend to be diurnally active year-round, but variation also has been reported, including some populations that have up to seven bouts of activity throughout the 24hour cycle averaging 1-1 hours/bout.

Movements, Home range and Social organization. Densities range from nearly 0 ind/ ha to 65 ind/ha and generally increase through summer until September and then decline over winter. A 3—4year population oscillation is typically reported, but sixand ten-year intervals have also been seen. Maximum life span is 20 months, but 10-12 months is much more common. Mean home ranges are 0-01-0-5 ha. Southern Redbacked Voles do not form colonies .

Status and Conservation. Classified as Least Concern on The IUCN Red List.

Bibliography. Bradley, Ammerman et al. (2014), Cook & Kirkland (1998), Gillis & Nams (1998), Hafner et al. (1998), Hall (1981), MacDonald & Cook (2009), Merritt (1981), Merritt & Merritt (1978), Musser & Carleton (2005), Runck & Cook (2005), Runck et al. (2009).