Meadow Voles Microtus Pennsylvanicus Research Articles

Use of biomarkers to show sub-cellular effects in meadow voles ( Microtus pennsylvanicus) living on an abandoned gold mine site

Run-off from mine tailings ponds constitutes the main anthropogenic release of arsenic in Canada. As a potential consequence, wildlife not normally exposed to arsenic under other circumstances may receive toxicologically relevant concentrations of arsenic compounds in their food and water. To test this hypothesis, and to determine if arsenic is being transported through trophic levels, the arsenic concentrations in members of a short food chain (soil–plant–meadow vole) were measured. Arsenic concentrations were higher in exposed organisms compared with those from a reference location. However, elevated concentrations of arsenic do not necessarily indicate impact, and consequently a biomonitoring study was undertaken to determine if there were sub-cellular effects of exposure in meadow voles ( Microtus pennsylvanicus) as a consequence of arsenic exposure. In this work, adenosine triphosphate (ATP) and liver glutathione (GSH) levels were used as biomarkers of exposure and the frequency of red blood cell micronuclei (mono- and polychromatic) was used as a biomarker of effect. ATP results were not conclusive but there was a statistically significant relationship between a reduction of GSH in vole livers and increased liver arsenic concentrations. A statistically significant relationship was also observed between increased micronucleated monochromatic red blood cells in voles from arsenic contaminated sites compared to a background location. The results of the GSH and monochromatic red blood cell investigations suggest that there are possible sub-cellular effects on these voles as a consequence of dietary arsenic exposure. This is the first field study in which such effects have been observed in voles living near mine tailings.

Analysis of Capture–Recapture Models with Individual Covariates Using Data Augmentation

I consider the analysis of capture-recapture models with individual covariates that influence detection probability. Bayesian analysis of the joint likelihood is carried out using a flexible data augmentation scheme that facilitates analysis by Markov chain Monte Carlo methods, and a simple and straightforward implementation in freely available software. This approach is applied to a study of meadow voles (Microtus pennsylvanicus) in which auxiliary data on a continuous covariate (body mass) are recorded, and it is thought that detection probability is related to body mass. In a second example, the model is applied to an aerial waterfowl survey in which a double-observer protocol is used. The fundamental unit of observation is the cluster of individual birds, and the size of the cluster (a discrete covariate) is used as a covariate on detection probability.

Same-sex social behavior in meadow voles: Multiple and rapid formation of attachments

Adult meadow voles ( Microtus pennsylvanicus) are solitary in the spring–summer reproductive season, but during winter months, females and males are socially tolerant and aggregate in groups. This behavioral difference is triggered by day length: female meadow voles housed in short, winter-like day lengths form same-sex partner preferences, whereas those housed in long, summer-like day lengths are less social. The present study demonstrates that same-sex social attachments in short day lengths are not exclusive; females formed concurrent attachments with more than one individual, and with non-kin as well as siblings. Partner preferences between females were established within one day of cohousing and did not intensify with greater durations of cohabitation. Males also formed same-sex social attachments, but unlike female affiliative behavior, male partner preferences were not significantly affected by day length. These data are discussed in the context of field behavior and the physiological mechanisms supporting social behavior in voles.

Partial and clearcut harvesting of dry Douglas-fir forests: Implications for small mammal communities

Dry Douglas-fir ( Pseudotsuga menziesii) forests offer a wide range of timber and non-timber values, which may benefit from a balanced timber harvest by variable retention systems with conservation of biodiversity. A major component of biodiversity are forest floor small mammal communities whose abundance and diversity serve as ecological indicators of significant change in forest structure and function from harvesting activities. This study was designed to test the hypotheses that abundance, reproduction, and survival of (i) the southern red-backed vole ( Myodes gapperi, formerly Clethrionomys gapperi), will decline; (ii) the deer mouse ( Peromyscus maniculatus), will be similar; and (iii) the meadow vole ( Microtus pennsylvanicus) and northwestern chipmunk ( Tamias amoenus), will increase, with decreasing levels of tree retention. Small mammal populations were live-trapped from 1994 to 1997 in replicated sites of uncut forest, 20% and 50% volume removal by single tree selection, 20%, 35%, and 50% patch cuts based on openings of 0.1–1.6 ha, and small 1.6 ha clearcuts in Douglas-fir forest near Kamloops, British Columbia, Canada. M. gapperi dominated the small mammal community, starting with an abundance of 74–98 animals/ha with mean values ranging from 33 to 51 animals/ha. In the two post-harvest years, abundance, reproduction, and survival of M. gapperi populations were consistently similar among uncut forest and the various levels of tree retention. Thereafter, M. gapperi was seldom found on the small clearcuts. M. pennsylvanicus, T. amoenus, and P. maniculatus occurred predominantly in clearcut sites. As with other types of forest disturbance, responses to our treatments were species-specific. The most striking result was the high abundance and productivity of M. gapperi populations in a dry forest ecosystem, a novel result for this bio-indicator species of closed-canopy forest conditions. At least with respect to small mammals, the retention systems studied seem to enable timber extraction and maintenance of mature forest habitat in these dry fir ecosystems.

Cover Crops Influence Meadow Vole Presence in Organic Orchards

Living mulch cover crops can improve soil health and build organic matter, yet their use in fruit orchards comes with a risk of encouraging meadow vole (Microtus pennsylvanicus), a rodent that can be destructive to fruit trees. Several living mulch cover crop species were assessed in an apple (Malus ×domestica) orchard understory along with wood chip mulch and bare ground. Desired species characteristics were weed competitiveness, low growth habit, nitrogen fixation, and potential rodent repellency. Legume species included birdsfoot trefoil (Lotus corniculatus), medic (Medicago spp.), and subterranean clover (Trifolium subterraneum), which were planted in solid stands as well as mixtures. Nonlegume species included sweet woodruff (Galium odoratum), sweet alyssum (Lobularia maritima), creeping thyme (Thymus serpyllum), and colonial bentgrass (Agrostis tenuis). Meadow vole presence was evaluated in fall and spring with point-intersect and run-length measurements. A legume mix (medic, birdsfoot trefoil, subterranean clover, and colonial bentgrass) had the highest meadow vole presence, with no reduction under the “sandwich” system of tilling either side of the tree trunks while leaving a cover crop in a narrow strip with the trunks. The nonlegume mix [colonial bentgrass, sweet alyssum, creeping thyme, and fivespot (Neomophila maculata)] had similar results. However, the sweet woodruff (planted in the “sandwich” system) had significantly lower presence of meadow voles than the other living mulches. Wood chip mulch, cultivation, and bare ground control were all similar, with very low presence, indicating low risk of meadow vole damage. The results from the sweet woodruff suggest that we need more research on the potential to select living mulches that are nonattractive or repellent to meadow voles for use in orchards.

Relative Resistance of Ornamental Flowering Bulbs to Feeding Damage by Voles

Many plants have mechanisms of physical or chemical resistance that protect them from herbivores in their environment. Vertebrates such as meadow voles (Microtus pennsylvanicus) cause significant damage to ornamental plantings and home gardens. Our goal was to identify flowering bulbs that could be used to design more herbivore-resistant home landscapes. Single-choice feeding trials with captive prairie voles (Microtus ochrogaster) were used to assess the relative resistance of 30 bulb varieties to deter rodents from consuming fresh plant material and freeze-dried, powdered bulb mixed with a preferred food (applesauce). Each fresh bulb and dried-bulb/applesauce mix was offered twice to 12 to 15 pairs of adult prairie voles. Bulb varieties that resulted in the lowest mean consumption were assumed to be the most resistant to feeding activity. With fresh bulbs, only tulips (Tulipa spp.) exhibited no resistance to prairie vole feeding. Dried-bulb/applesauce mixes containing hyacinth (Hyacinth spp.), crocus (Crocus spp.), corn leaf iris (Iris bucharica), dutch and dwarf iris (Iris reticulata), onion (Allium spp.), and squill (Scilla siberica) were also readily consumed, and thus, these bulbs could be damaged at sites with high rodent activity. Daffodil (Narcissus spp.), painted arum (Arum italicum), camass (Camassia leichtlinii), glory-of-the-snow (Chinodoxa forbesii), autumn crocus (Colchicum spp.), crown imperial (Fritillaria imperialis), persian fritillaria (Fritillaria persica), snowdrop (Galanthus nivalis), and grape hyacinth (Muscari armeniacum) bulbs were resistant to prairie vole feeding in both forms (fresh bulbs and dried-bulb/applesauce mixes). Consequently, all of the specialty flower bulbs tested, except tulip, exhibited some resistance to prairie vole feeding in their fresh form, and could be suitable for designing herbivore-resistant landscapes.

Relative Resistance of Ornamental Flowering Bulbs to Feeding Damage by Voles

Many plants have mechanisms of physical or chemical resistance that protect them from herbivores in their environment. Vertebrates such as meadow voles (Microtus pennsylvanicus) cause significant damage to ornamental plantings and home gardens. Our goal was to identify flowering bulbs that could be used to design more herbivore-resistant home landscapes. Single-choice feeding trials with captive prairie voles (Microtus ochrogaster) were used to assess the relative resistance of 30 bulb varieties to deter rodents from consuming fresh plant material and freeze-dried, powdered bulb mixed with a preferred food (applesauce). Each fresh bulb and dried-bulb/applesauce mix was offered twice to 12 to 15 pairs of adult prairie voles. Bulb varieties that resulted in the lowest mean consumption were assumed to be the most resistant to feeding activity. With fresh bulbs, only tulips (Tulipa spp.) exhibited no resistance to prairie vole feeding. Dried-bulb/applesauce mixes containing hyacinth (Hyacinth spp.), crocus (Crocus spp.), corn leaf iris (Iris bucharica), dutch and dwarf iris (Iris reticulata), onion (Allium spp.), and squill (Scilla siberica) were also readily consumed, and thus, these bulbs could be damaged at sites with high rodent activity. Daffodil (Narcissus spp.), painted arum (Arum italicum), camass (Camassia leichtlinii), glory-of-the-snow (Chinodoxa forbesii), autumn crocus (Colchicum spp.), crown imperial (Fritillaria imperialis), persian fritillaria (Fritillaria persica), snowdrop (Galanthus nivalis), and grape hyacinth (Muscari armeniacum) bulbs were resistant to prairie vole feeding in both forms (fresh bulbs and dried-bulb/applesauce mixes). Consequently, all of the specialty flower bulbs tested, except tulip, exhibited some resistance to prairie vole feeding in their fresh form, and could be suitable for designing herbivore-resistant landscapes.

Enclosure size and hormonal state affect timing of nest return in female meadow voles (Microtus pennsylvanicus).

We investigated 2 aspects of the hormonal regulation of maternal behavior in meadow voles (Microtus pennsylvanicus): (a) when the transition in maternal responsiveness from primarily hormonal control to regulation by pup cues occurs; and (b) the effect of housing enclosure size on maternal nest attendance in voles injected with a prolactin suppressant, cysteamine hydrochloride (150 mg/kg) on Postnatal Day 2. In Experiment 1, meadow voles required 96 hr of pup contact to finish the transition from hormonal to pup-mediated maternal behavior; a period longer than found in other rodents. In Experiment 2, females housed in larger enclosures spent less time with pups after drug injection, primarily because they increased the amount of time they stayed away from the nest each time they left. In contrast, drug-treated females in standard cages showed no change in their patterns of nest attendance, possibly due to the presence of salient cues from nearby pups. Under naturalistic conditions, a female vole's hormonal state may regulate nest approach, and help establish the necessary alternation between leaving the nest (e.g., to forage) and attending pups.

Cover Crops Influence Meadow Vole Presence in Organic Orchards

Living mulch cover crops can improve soil health and build organic matter, yet their use in fruit orchards comes with a risk of encouraging meadow vole (Microtus pennsylvanicus), a rodent that can be destructive to fruit trees. Several living mulch cover crop species were assessed in an apple (Malus ×domestica) orchard understory along with wood chip mulch and bare ground. Desired species characteristics were weed competitiveness, low growth habit, nitrogen fixation, and potential rodent repellency. Legume species included birdsfoot trefoil (Lotus corniculatus), medic (Medicago spp.), and subterranean clover (Trifolium subterraneum), which were planted in solid stands as well as mixtures. Nonlegume species included sweet woodruff (Galium odoratum), sweet alyssum (Lobularia maritima), creeping thyme (Thymus serpyllum), and colonial bentgrass (Agrostis tenuis). Meadow vole presence was evaluated in fall and spring with point-intersect and run-length measurements. A legume mix (medic, birdsfoot trefoil, subterranean clover, and colonial bentgrass) had the highest meadow vole presence, with no reduction under the “sandwich” system of tilling either side of the tree trunks while leaving a cover crop in a narrow strip with the trunks. The nonlegume mix [colonial bentgrass, sweet alyssum, creeping thyme, and fivespot (Neomophila maculata)] had similar results. However, the sweet woodruff (planted in the “sandwich” system) had significantly lower presence of meadow voles than the other living mulches. Wood chip mulch, cultivation, and bare ground control were all similar, with very low presence, indicating low risk of meadow vole damage. The results from the sweet woodruff suggest that we need more research on the potential to select living mulches that are nonattractive or repellent to meadow voles for use in orchards.

Self‐Grooming Response of Meadow Voles to the Odor of Opposite‐Sex Conspecifics in Relation to the Dietary Protein Content of Both Sexes

AbstractMany animals self‐groom when they encounter the scent marks of opposite‐sex conspecifics. Self‐grooming transmits odiferous substances that contain information about the groomer’s condition, which is affected by its nutritional state. We tested the hypothesis that the amount of time that individuals self‐groom to opposite‐sex conspecifics is affected by the amount of protein in their diet and that of the scent donor. We did so by feeding meadow voles (Microtus pennsylvanicus) a diet containing 9%, 13%, or 22% dietary protein for 30 d and observing their self‐grooming behavior when they were exposed to bedding scented by an opposite‐sex conspecific (odor donor) fed one of the three diets, or fresh cotton bedding (control). The hypothesis was partially supported. We found that the protein content of the diet of male and female groomers did not affect the amount of time they self‐groomed. However, the protein content of the diet of male odor donors affected the amount of time that female voles spent self‐grooming. Female voles self‐groomed more in response to male odor donors fed a 22% protein‐content diet than to those produced by male odor donors fed either a 9% or a 13% protein‐content diet. Interestingly, the amount of time males self‐groomed was not affected by the protein content of the diet of the female odor donor. These results may, in part, be explained by the natural history of free‐living meadow voles, sex differences in costs associated with mate attraction and reproduction, and the direct or indirect benefits that females receive from males fed a diet high in protein content.

Aspen Stands as Small Mammal “Hotspots” Within Dry Forest Ecosystems of British Columbia

Forest stands of trembling aspen (Populus tremuloides) have been shown to support relatively abundant and diverse faunal communities, but this potential has not been extensively explored within the dry interior forests of British Columbia, Canada. These forests are primarily composed of conifers, particularly stands of Douglas-fir (Pseudotsuga menziesii), with only a small proportion consisting of trembling (or quaking) aspen. During 2005 and 2006, we live-trapped and compared small mammal assemblages within rare aspen stands to those in neighboring Douglas-fir and mixed-wood (aspen + Douglas-fir) stands. We captured a total of 4246 individuals of 10 small mammal species during 15,761 trap nights—with 54% of individuals captured in aspen stands. Commonly captured species included the deer mouse (Peromyscus maniculatus), southern red-backed vole (Myodes gapperi), long-tailed vole (Microtus longicaudus), montane vole (Microtus montanus), meadow vole (Microtus pennsylvanicus), yellow-pine chipmunk (Tamias am...

Influence of rodent abundance on nesting success of prairie waterfowl

Most waterfowl nesting failure in the prairie biome is attributed to predation. However, the contribution of small mammal abundance to the prairie predator–prey cycle and how this affects waterfowl productivity is not known. We modelled seasonal variability of nesting success, including a number of habitat and nest-related variables, to quantify influence of rodent abundance for prairie nesting waterfowl for six study sites in the Prairie Pothole Region of Canada, 1996–1998. We estimated there is a curvilinear relationship between the abundance of meadow voles ( Microtus pennsylvanicus (Ord, 1815)) and the nesting success of ducks. The relationship has characteristics of the alternate prey hypothesis at low vole density and characteristics of the shared prey hypothesis at higher densities. At low vole densities, duck nests appear to be buffered from predation by voles but, at higher densities, nesting success was affected negatively. We recommend that predator–prey dynamics should be included as an integral part of management plans for nesting waterfowl and suggest further research using rigorous experiment design to elucidate mechanisms and pathways responsible for this observed relationship.

Genetic relationships of meadow vole (Microtus pennsylvanicus) populations in central Appalachian wetlands

We sequenced and compared variation within a 375-base-pair segment of the mitochondrial DNA control region of 323 meadow voles ( Microtus pennsylvanicus (Ord, 1815)) among 14 populations to determine the influence of past and present landscape connectivity among isolated wetlands in the central Appalachian Mountains. To best explain observed differences among sites, we used genetic and landscape-level (GIS) data to test a null hypothesis (no genetic differences) and three alternate explanations of significant variation owing to founder effects, effective population size, or isolation by distance. Sequencing results revealed 16 distinct haplotypes (1–8 haplotypes/site), with two present in samples from most wetlands, and half of the remaining haplotypes concentrated in specific geographic clusters. Our findings best support the explanation that founder effects have influenced current genetic patterns among sites. These founder effects are likely due to historical land-use activities such as exploitative logging (ca. 1880–1920; creating early successional habitats for voles) and subsequent forest regeneration over the past half century; they were also likely influenced by postglacial colonization patterns. Therefore, current genetic diversity in these populations seems to largely reflect the number and source of voles that successfully colonized these isolated wetlands during the window of opportunity immediately following extensive logging.

Late Pleistocene Vertebrate, Plant and Insect Remains from the lnnerkip Site, Southwestern Ontario

Remains of white-tailed deer (Odocoileus virginianus), meadow voles (Microtus pennsylvanicus), muskrat (Ondatra zibethicus) and Blanding's turtle (Emydoidea blandingi) have been recovered from a peat deposit exposed on a tributary of the Thames River in southwestern Ontario. Numerous insect fossils, principally Coleoptera, and a variety of plants recovered from the same stratigraphie horizon have permitted a partial reconstruction of a larger community at the site of peat deposition. The plant, vertebrate and invertebrate fossils represent part of an assemblage which existed in. or beside, a small pond. Deposition probably occurred at the end of the Sangamon Interglaciation (Isotope Stage 5e) or during warm Early Wisconsinan interstadial (Isotope Stage 5c or 5a).

EXPERIMENTAL INOCULATION OF MEADOW VOLES (MICROTUS PENNSYLVANICUS), HOUSE MICE (MUS MUSCULUS), AND NORWAY RATS (RATTUS NORVEGICUS) WITH MYCOBACTERIUM BOVIS

Mycobacterium bovis has a wide host range that includes several wildlife species, and this can hamper attempts to eradicate bovine tuberculosis from livestock. The purpose of this study was to determine if common rodent species, namely meadow voles (Microtus pennsylvanicus), house mice (Mus musculus), and Norway rats (Rattus norvegicus), that inhabit the bovine tuberculosis endemic area of Michigan, can be experimentally infected with M. bovis. The objectives of the study were: 1) to determine if these rodent species can be infected, and if so, to document attendant pathologic processes/pathogenesis; 2) to detect any fecal shedding of M. bovis; and 3) to evaluate the relative susceptibility of the three species to M. bovis infection. For each species (n=36) there were two treatment (n=12/group) and one or two control groups depending on species (n=6-12/group); the maximum study duration was 60 days. The meadow vole treatments consisted of high dose inocula that were given by oral or intranasal routes, whereas the house mice and Norway rats were given only oral inocula at either a high or low dose. Of the three species, meadow voles were most susceptible to M. bovis infection. Upon intranasal inoculation, all 12 voles were infected as determined by gross and microscopic lesions and culture of M. bovis from tissue and feces. Seven of the 12 meadow voles inoculated orally were infected. House mice also were susceptible; M. bovis was isolated from 14 of 24 animals. Only one Norway rat in the high dose treatment group was positive by culture and this was the only animal from which minimal attendant lesions were observed. Results of this study indicate that meadow voles and house mice can be infected with M. bovis and might serve as spillover hosts. Concerted efforts should, therefore, be made to reduce or eliminate these rodents on premises where M. bovis-infected livestock are present.

The Effects of Matrix Structure on Movement Decisions of Meadow Voles (Microtus pennsylvanicus)

The composition of the landscape between patches (the matrix) can have important effects on movement rates that potentially outweigh the effects of patch size and isolation. We conducted a small-scale experiment with radiocollared meadow voles (Microtus pennsylvanicus) to quantify the effects of matrix habitat on movement behavior of voles. Habitat patches were created within an enclosure and connected by pathways of different vegetation heights designed to represent different levels of predation risk to the voles. Voles were fitted with radiocollars and tracked 4 times daily for 1–3 weeks. We quantified the probability that a vole would transition through a particular matrix type (i.e., cross a habitat edge) and estimated transition probabilities using multinomial random effects models. These methods along with permutation tests were used to test whether the transition probabilities of voles could be modeled by assuming common movement rules such as “random,” “static choice” when all voles always choose the same type of pathway, or “probabilistic” when voles are most likely to choose a pathway of tall vegetation and select other pathway types in inverse order of the relative risk associated with the pathway. Vole movement decisions in our experimental landscapes reflected a probabilistic approach to decision making in which pathways were chosen in proportion to risk associated with travel. Quantification of transition probabilities through different matrix types is necessary for modeling animal movements in complex environments.

Seasonal changes and wind dependence of thermal conductance in dorsal fur from two small mammal species ( Peromyscus leucopus and Microtus pennsylvanicus)

(1) We measured the thermal conductance of dorsal pelage from meadow voles ( Microtus pennsylvanicus) and white-footed mice ( Peromyscus leucopus) during summer and winter. (2) Thermal conductance was lower in the winter pelage of both species, but the seasonal change was greater in meadow voles. (3) The form of wind speed dependence was determined by fitting a nonlinear curve of the form a+ bu c to data recorded at five wind speeds. The most appropriate exponent c was between 0.908 and 0.987, depending on species and season. These values are common and suggest that thermal and dynamic forces are important.

Do animals select habitat at small or large scales? An experiment with meadow voles (Microtus pennsylvanicus)

Habitat and patch use are crucial to the dynamics of populations and the structure of ecological communities. But ecologists have not rigorously tested whether animals choose habitat at small or large scales. If individuals base their patch and habitat choices on fine-scale differences in habitat, then their use of different sites should correspond with measures of microhabitat at those sites. But if individuals use density to assess and respond to habitat at larger spatial scales, then site use should correspond with the scale of density-dependent habitat selection. We tested these predictions with experiments that measured microhabitat and monitored the use of capture sites by meadow voles ( Microtus pennsylvanicus Ord, 1815) in 0.25 ha old-field enclosures. We varied the density of voles in pairs of adjacent enclosures and tested for density-dependent habitat selection. Then we assessed whether their frequency of captures at trapping stations was best predicted at the small scale of microhabitat or at the much larger scale of enclosures where density varied. The voles selected habitat at different scales. When the use of enclosures was predicted by density, the scale of density-dependent choice trumped the use of small-scale patches. And when voles selected amongst different small-scale patches, their use of enclosures was independent of density. These results suggest that assessments of spatial scale in habitat use must include tests for both scale- and density-dependent habitat choice.

Effects of Prebaiting on Small Mammal Trapping Success in a Morrow's Honeysuckle‐Dominated Area

Abstract:Researchers have obtained mixed results in studies that use prebaiting to enhance small mammal trapping success. In 2004–2005 we tested the effects of prebaiting on small mammal trapping success in an exotic and invasive shrub community, Morrow's honeysuckle (Lonicera morrowii), using 4 80 × 120‐m live trapping grids at Fort Necessity National Battlefield in Fayette County, Pennsylvania, USA. We randomly assigned traps to 1 of 3 trapping methods: we prebaited one‐third of the traps 2 nights (n= 3,508 trap‐nights), one‐third one night (n= 3,492 trap‐nights), and one‐third had no prebaiting (n= 3,509 trap‐nights). We compared small mammal richness, diversity, and relative abundance (no. captures/100 trap‐nights) of white‐footed mice (Peromyscus leucopus; n= 462 captures), meadow voles (Microtus pennsylvanicus; n= 89 captures), meadow jumping mice (Zapus hudsonius; n= 221 captures), masked shrews (Sorex cinereus; n= 87 captures), and shorttail shrews (Blarina brevicauda; n= 78 captures) among prebaited traps and non‐prebaited traps. On the first day of trapping, as well as all 4 days combined, richness, diversity, and relative abundance for all species were similar among traps that we had prebaited for 2 nights, one night, and zero nights (P= 0.856). Moreover, total number of captures was similar among prebaiting treatments (P= 0.197). These results suggest that prebaiting does not enhance trapping success for small mammals in a landscape dominated by a dense, exotic shrub. We recommend that managers do not employ prebaiting in areas with similar small mammal species composition in an attempt to increase trapping success, as we did not record a difference in trapping success in prebaited traps compared to non‐prebaited traps.

ESTIMATING SPECIES-SPECIFIC SURVIVAL AND MOVEMENT WHEN SPECIES IDENTIFICATION IS UNCERTAIN

Incorporating uncertainty in the investigation of ecological studies has been the topic of an increasing body of research. In particular, mark-recapture methodology has shown that incorporating uncertainty in the probability of detecting individuals in populations enables accurate estimation of population-level processes such as survival, reproduction, and dispersal. Recent advances in mark-recapture methodology have included estimating population-level processes for biologically important groups despite the misassignment of individuals to those groups. Examples include estimating rates of apparent survival despite less than perfect accuracy when identifying individuals to gender or breeding state. Here we introduce a method for estimating apparent survival and dispersal in species that co-occur but that are difficult to distinguish. We use data from co-occurring populations of meadow voles (Microtus pennsylvanicus) and montane voles (M. montanus) in addition to simulated data to show that ignoring species uncertainty can lead to biased estimates of population processes. The incorporation of species uncertainty in mark-recapture studies should aid future research investigating ecological concepts such as interspecific competition, niche differentiation, and spatial population dynamics in sibling species.