Lemming winter nestsWinter nests found in searches of trapping grids each summer, and indications of predation by ermineYearSummer when nest was found (1994-1997)Textyyyy Lemming winter nestsWinter nests found in searches of trapping grids each summer, and indications of predation by ermineGridTrapping grid, 1-7. Grid 4 was protected from predators; grids 1-3 were not. In 1994 we searched three additional unprotected grids (5-7) in upland habitat.Text Lemming winter nestsWinter nests found in searches of trapping grids each summer, and indications of predation by ermineErmineOccNest occupied by ermine, i.e. lined with fur and containing ermine scats. 0=No, 1=YesNumeric0 or 1 Lemming winter nestsWinter nests found in searches of trapping grids each summer, and indications of predation by ermineInclOtherSignNest occupied or with other signs of ermine predation (a lemming skin in 1996 and tufts of fur in 1997). 0=No, 1=YesNumeric0 or 1 Lemming winter nestsWinter nests found in searches of trapping grids each summer, and indications of predation by ermineTransect widthWidth of transects walked by observers on trapping grids. 3 m in 1994 and 1995; 6 m in 1996 and 1997 Numericm Male Dicro reprod condReproductive condition of live-captured male DicrostonyxYearYear captured, 1995-1997Textyyyy Male Dicro reprod condReproductive condition of live-captured male DicrostonyxGridTrapping grid, 1-4. Grid 4 was protected from predators; grids 1-3 were notText Male Dicro reprod condReproductive condition of live-captured male DicrostonyxTagEar tag number. An individual may have been captured in more than one period within a year, and possibly in more than one yearText Male Dicro reprod condReproductive condition of live-captured male DicrostonyxWtClassWeight class. Juvenile <25 g, Subadult 25-49 g, Adult ?50gText Male Dicro reprod condReproductive condition of live-captured male DicrostonyxMaleRepReproductive condition (0 not in reproductive condition (abdominal testes), 1 in reproductive condition (scrotal testes)Numeric0 or 1 Male Dicro reprod condReproductive condition of live-captured male DicrostonyxPeriodPeriod of year when captured: June, JunJul, JulAug, AugText Female Dicro reprod condReproductive condition of live-captured female DicrostonyxYearYear captured, 1995-1997Textyyyy Female Dicro reprod condReproductive condition of live-captured female DicrostonyxGridTrapping grid, 1-4. Grid 4 was protected from predators; grids 1-3 were notText Female Dicro reprod condReproductive condition of live-captured female DicrostonyxTagEar tag number. An individual may have been captured in more than one period within a year, and possibly in more than one yearText Female Dicro reprod condReproductive condition of live-captured female DicrostonyxWtClassWeight class. Juvenile <25 g, Subadult 25-49 g, Adult ?50gText Female Dicro reprod condReproductive condition of live-captured female DicrostonyxFemaleRepReproductive condition (0 not in reproductive condition (closed pubic symphysis, nipples not enlarged, not obviously pregnant), 1 in reproductive condition (open pubic symphysis or enlarged nipples or obviously pregnant)Numeric0 or 1 Female Dicro reprod condReproductive condition of live-captured female DicrostonyxPeriodPeriod of year when captured: June, JunJul, JulAug, AugText Oestrus DicroOestrus of live-captured Dicrostonyx. Recorded only in 1997 and July and August 1996.YearYear captured, 1996-1997Textyyyy Oestrus DicroOestrus of live-captured Dicrostonyx. Recorded only in 1997 and July and August 1996.GridTrapping grid, 1-4. Grid 4 was protected from predators; grids 1-3 were notText Oestrus DicroOestrus of live-captured Dicrostonyx. Recorded only in 1997 and July and August 1996.TagEar tag number. An individual may have been captured in more than one period within a year, and possibly in more than one yearText Oestrus DicroOestrus of live-captured Dicrostonyx. Recorded only in 1997 and July and August 1996.WtClassWeight class. Juvenile <25 g, Subadult 25-49 g, Adult ?50gText Oestrus DicroOestrus of live-captured Dicrostonyx. Recorded only in 1997 and July and August 1996.FemaleRepOestrus condition (0 not in oestrus (imperforate vagina), 1 in oestrus (perforate vagina)Numeric0 or 1 Oestrus DicroOestrus of live-captured Dicrostonyx. Recorded only in 1997 and July and August 1996.PeriodPeriod of year when captured: June, JunJul, JulAug, AugText Dicrostonyx body massBody mass of live-captured DicrostonyxYearYear captured, 1995-1997Textyyyy Dicrostonyx body massBody mass of live-captured DicrostonyxGridTrapping grid, 1-3. These three grids were not protected from predatorsText Dicrostonyx body massBody mass of live-captured DicrostonyxTagEar tag number. An individual may have been captured in more than one period within a year, and possibly in more than one yearText Dicrostonyx body massBody mass of live-captured DicrostonyxPeriodPeriod of year when captured: June, JunJul, JulAug, AugText Dicrostonyx body massBody mass of live-captured DicrostonyxMassBody massNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)YearYear scat collected (1994-1997)Textyyyy Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)ScatIDScat identifier, not unique between yearsText Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)DateCollectedDay and month scat was collectedTextdd-mmm Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)DenIDName of den where scat was collected. If not from a den, then "N"Text Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)AdJuvAdult (A) or juvenile (J) fox. For scats collected at dens in July and August 1995 and 1996, classification was based on scat diameter. Other scats were assumed to be from adults.Text Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PeriodPeriod of year when scat was collected. Format is yyyy-n. n=0 means a winter scat collected from snow in spring. Within a year, period n=1-4 corresponds to dates on columns of Supplementary Table S1.Text Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)ScatWtWeight of dried scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MLemBonesMass of lemming bones in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MGrSqBonesMass of ground squirrel bones in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MHareMass of arctic hare bones in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MLbirdMass of bones from large bird (anseriform, galliform) in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MSbirdMass of bones from small bird (passeriform, charadriiform) in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MEggshellMass of eggshell in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MInsectMass of insect parts in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MVegMass of vegetation in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MShrewMass of shrew bones in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MInvertMass of invertebrate (non-insect) exoskeleton in scat Numericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MParasiteMass of parasites in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MCaribouMass of caribou hair in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MUnidMass of unidentified material in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MSyntheticMass of synthetic material in scatNumericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)UnidBoneSizeSize of unidentified bones. A taxon with similarly sized bones (Gr sq = ground squirrel, Lbird = large bird) or Sm=small.Text Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)CommentNotes on den, freshness, eggshell, or other materialText Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)MRemainderMass of "remainder" without above items Numericg Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctMicrotineFurMicrotine fur in remainderNumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctGrSqFurGround squirrel fur in remainderNumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctLfeathLarge feathers in remainder (anseriform, galliform)NumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctSfeathSmall feathers in remainder (passeriform, charadriiform) NumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctVegVegetation in remainderNumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctInorgInorganic material in remainderNumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctHareHare fur in remainderNumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctFoxFox fur in remainderNumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctEggEggshell in remainderNumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctInsectInsect parts in remainderNumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)PctUnidTissueUnidentified tissue in remainderNumericPercentage Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)NoteNotes on unidentified tissueText Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)NTeethDicroNumber of Dicrostonyx molar teethNumericCount Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)NTeethLemmusNumber of Lemmus molar teethNumericCount Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)NumDicroMinimum number of Dicrostonyx in scat, based on teethNumericCount Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)NumLemmusMinimum number of Lemmus in scat, based on teethNumericCount Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)NumLemOtherMinimum number of lemmings (species not identifiable) in scat, based on other contents (fur, bones, feet, tails)NumericCount Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)NumDicroOtherMinimum number of Dicrostonyx in scat, based on teeth and other contents (fur, bones, feet, tails)NumericCount Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)NumLemmusOtherMinimum number of Lemmus in scat, based on teeth and other contents (fur, bones, feet, tails)NumericCount Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)Ulna1Length of ulna 1 in scatNumericmm Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)Ulna2Length of ulna 2 in scatNumericmm Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)UpperMolarRow1Length of upper molar row 1 in scatNumericmm Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)UpperMolarRow2Length of upper molar row 2 in scatNumericmm Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)LowerMolarRow1Length of lower molar row 1 in scatNumericmm Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)LowerMolarRow2Length of lower molar row 2 in scatNumericmm Fox scatsAnalysis of fox scat contents (Methods are in Supplementary Calculations S2)SpMolarsSpecies of molar row(s), D (Dicrostonyx) or L (Lemmus)Text Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)SpeciesPredatory bird species. GLGU, PEFA, RLHA, SACR, SEOW, SNOW refer respectively to glaucous gull, peregrine falcon, rough-legged hawk, sandhill crane, short-eared owl, snowy owlText Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)YearYear pellet collected (1994-1997)Textyyyy Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)PelletIDPellet identifier, not unique between yearsText Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)DateCollectedDay and month pellet was collectedTextdd-mmm Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)FromNestWas pellet collected from a nest, Y or NText Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)LocationLocation where collected, including whether on snowText Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)CommentComment on pellet freshness, etc.Text Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)NumDicroMinimum number of Dicrostonyx, based on teethNumericCount Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)NumLemmusMinimum number of Lemmus, based on teethNumericCount Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)NumMicrotusMinimum number of Microtus oeconomus voles, based on teethNumericCount Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)NumSorexMinimum number of Sorex cinereus shrews, based on teethNumericCount Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)PADicroPresence (1) or absence (0) of Dicrostonyx, based on teeth, fur, clawsNumeric0 or 1 Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)PALemmusPresence (1) or absence (0) of Lemmus, based on teethNumeric0 or 1 Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)PMicrotusPresence (1) of Microtus oeconomus voles, based on teethNumeric1 or blank Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)PSorexPresence (1) of Sorex cinereus shrews, based on teethNumeric1 or blank Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)GrSqPresence (1) of ground squirrel remainsNumeric1 or blank Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)BirdPresence (1) of bird remainsNumeric1 or blank Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)EggshellPresence (1) of eggshellNumeric1 or blank Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)InsectsPresence (1) of insect remainsNumeric1 or blank Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)VegPresence (1) of vegetationNumeric1 or blank Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)InorgPresence (1) of inorganic materialNumeric1 or blank Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)ClamshellPresence (1) of clam shellNumeric1 or blank Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)UnidPresence (1) of unidentified materialNumeric1 or blank Avian predator pelletsAnalysis of pellets from avian predators (Methods are in Supplementary Calculations S3)ClawsPresence (1) of clawsNumeric1 or blank