Small Mammals


Differentiation of White-Footed Mice from Deer Mice Using Salivary Amylase and Cellulose Acetate Electrophoresis
Kelly Lorenz, Joe Whittaker, Lauryn Petrich, Vanessa Petrich

White-footed (Peromyscus leucopus) and deer mice (Peromyscus maniculatus) are two distinct species and are physiologically differentiable.  However, their morphology overlaps to the extent that they cannot be reliably differentiated in the field.  Historically, biologists have attempted to use cranial measurements and physical characteristics such as ear and tail length and the distinctiveness of tail coloration. These measurements have always overlapped or were subject to observer bias.  As the result of climate change, the deer mouse range has been constricted as the white-footed mouse range has increased, resulting in greater overlap of the two species ranges.  At the same time, their measurements and morphological traits have increased in their degree of overlap.   Previous research has indicated that these morphological traits can only identify between 55% and 66% of these species correctly.  Unlike morphological comparisons, salivary amylase allozymes through cellulose acetate electrophoresis provides a method of reliable differentiation.  Saliva samples were collected from restored and remnant prairies, and woodlands in Minnesota from 2004 to 2019. We analyzed samples from 2017 to present and made comparisons with morphological data that was collected in the field.  Rapid identification of these species in the field will enable us to understand their ecology more efficiently.  Identification is also important as they are reservoirs for Lyme disease (white-footed mice) and hantavirus (deer mice).  

Squirrels Going Nuts: Exploring the Interplay between Squirrel Foraging Dynamics and Plastic Pollution
Olivia Vergin, Faith James, Jennifer Sweatman, Joe Whittaker

Urban sprawl fragments habitats and forces wildlife to inhabit human-dominated landscapes. Eastern gray squirrels (Sciurus carolinensis) and American red squirrels (Tamiasciurus hudsonicus) adapted behaviors to increase fitness in urban niches, including foraging from anthropogenic food sources. Squirrels foraging from anthropogenic waste inadvertently consume plastics that accumulate in the body. We hypothesized that campus squirrels consume plastic waste when foraging through anthropogenic sources. To assess the availability of anthropogenic food sources and their impact on local wildlife, we identified anthropogenic and organic food sources around campus and quantified microplastic content in urban and rural squirrels. We determined plastic content in the gastrointestinal (GI) tracts of squirrels by chemically digesting organs to extract microplastics (MPs), then characterized MPs by size, shape, and color. After standardizing the number of MPs by the mass of the GI tract, we found a mean of 0.311 ± 0.326 MPs g⁻¹ GI tract in urban squirrels and a higher mean for rural squirrels at 0.469 ± 0.392 MPs g⁻¹ GI tract. We used a Kruskal Wallis test and found that this difference was not statistically significant (p = 0.123). We observed and analyzed intraspecies dynamics, including squirrels’ nesting locations and primary food sources, using radio telemetry technology; we characterized behaviors via an ethogram. To quantify the plastic composition of anthropogenic food sources, we conducted waste audits from outdoor garbage containers. Squirrel sightings, garbage locations, and nests were recorded using the GIS Field Maps application and spatially analyzed through ArcGIS software. We will present our findings to the Concordia College community to highlight issues concerning plastic waste and inform campus policy to positively impact Concordia’s local ecosystem.

Sexual Dimorphism in Black-Tailed Prairie Dogs from North Dakota
Donna Bruns Stockrahm, Elizabeth Meidl

Black-tailed prairie dogs (Cynomys ludovicianus) are social, diurnal ground squirrels that live in colonies and exhibit sexual dimorphism with males generally being larger than females.  Differences in skull measurements and body weights have been documented in the literature, but limited information is available where multiple body features of the same animals were compared between males and females.  For this study, we compared body weight, body length, dried eye-lens weight, zygomatic breadth, greatest skull length, least inter-orbital breath, and humerus length between males and females of the same age.  Skulls, humeri, and eyeballs from prairie dogs were collected from late May to late July 1977 from Billings County, North Dakota, and body weights and lengths were recorded.  Bone materials were cleaned, dried, and measured with calipers to one-hundredth of a mm.  Eyeballs were fixed in formalin, then lenses were removed and dried to constant weight to the nearest 0.2 mg.  Specimens (n=192) were divided into two groups: yearlings and 2+ year-olds, so that females and males were compared with those of a comparable age.  Pups were not included in this analysis.  One-tailed t-tests indicated that means of all the parameters were significantly higher (P<0.05) for males than for females in the yearling group and the 2+ year-old group with the exception of dried eye-lens weight for the latter group, perhaps due to leveling off with age.

Evaluation of a Technique to Dispense Anthelmintic Bait to Control Baylisascaris procyonis in Raccoons
Grace Lewis, uma ramakrishnan

The Allegheny woodrat (Neotoma magister) is declining through most of its range due to a variety of factors including habitat loss and disease. Raccoon roundworm (Baylisascaris procyonis) is one of the causes of woodrat mortality, with raccoons (Procyon lotor) serving as the primary reservoir for this parasite. B. procyoni is fatal to intermediate hosts such as N. magister. The goal of this study was to test the effectiveness in attracting raccoons to anthelmintic baits sheltered within a specialized tube. The tube was constructed using PVC pipe 30cm in length and 15cm in diameter. The tube was fitted with a socket cap at one end to shelter the bait. An 8cm hole was made on the side of the tube, through which the target species could access the anthelmintic bait. The bait tube was attached to trees approximately 20 cm off the ground. The study was conducted over a period of 7 weeks in spring. A total of 31 bait tubes were placed along the 3 km perimeter, with approximately 100 m between tubes. Some bait tubes were paired with motion sensitive cameras every 300 m with a total of 10 cameras deployed. The photographic evidence indicated that only P.lotor could access the bait, with 11 visits recorded on camera. The bait tubes were checked every week, and the bait had to be replenished 17 times over the study period. The only non-target species visits recorded were a single porcupine (Erethizon dorsatum) and 21 flying squirrel (Glaucomys sabrinus) visits. While this approach is relatively inexpensive, the next step in the study is to measure the effort it would take to use this technique over a larger area. Finally, we need to measure changes in B. procyoni in raccoons in treated areas and untreated areas.

Abundance and Occupancy of Snowshoe Hare Predators on the Leech Lake Band of Ojibwe Reservation – SRIP
Kimberly Shelton, Tanya Roerick, Jonathan Gilbert, Jacob Haus
ABSTRACT Wabooz (snowshoe hare [Lepus americanus]) are a culturally significant animal and an important food and fur source for the Leech Lake Band of Ojibwe (LLBO). Snowshoe hare populations on the reservation are declining; an ongoing study found 91% of all hare mortalities were caused by predation, primarily gidigaa-bizhiw (bobcat [Lynx rufus]), ojiig (fisher [Pekania pennanti]), and waabizheshi (American marten [Martes americana]). Snowshoe hare, American marten, and fisher are currently listed on the LLBO Threatened, Endangered, and Sensitive Species list.  Research using culturally appropriate techniques is crucial to the future management and conservation of sensitive predator species on tribal land, and we evaluated two non-invasive monitoring techniques for long-term use by tribal wildlife managers. Sampling methods measured abundance and occupancy of bobcat, fisher, and American marten across the LLBO reservation; spatially explicit capture-recapture using remote cameras, and occupancy modelling using snow-tracking. We randomly established eight 5-km transects each divided into 1-km replicates (40 total) ≥1km from marked roads. Transects were surveyed once between January-March 2021. Snow-tracking yielded detections of bobcat, fisher and marten at 5%, 23% and 20% of transect replicates, respectively. We randomly generated 40 camera locations stratified by landcover type (20 sites within white cedar cover type, 20 sites outside white cedar cover type) and ≤1km from winter plowed roads. Each site included a baited platform and white-flash camera set ~1.5m above ground for unique identification of fisher/marten, and one infrared camera at ground level for bobcat. Each camera site was active for 21 days between January-March 2021. Cameras yielded identifiable detections of 2 bobcat, 3 fisher and 0 marten, providing insufficient data for planned density estimates. These preliminary data will be combined with 2022 field season data to better inform the population management of snowshoe hare populations and their predators.
Muskrats as Ecosystem Engineers in Great Lakes Coastal Wetlands – SRIP
Megan Bos, Thomas Gehring
With muskrat (Ondatra zibethicus) populations declining across North America and the potential role they play as ecosystem engineers, it is important to understand the effect they have on wetland systems. Ecosystem engineers are organisms that impact their environment by modifying, maintaining, or creating habitat and by affecting the availability and amount of resources. By consuming cattails (Typha spp.) as a primary source of food and using them as building materials, muskrats create perforations within otherwise contiguous stands of vegetation. These open water areas may provide habitat for a greater number and diversity of species and may allow an access point for invasive plant species. While the chemical and physical properties of water determine the foundational abiotic environment in coastal wetlands, it is unknown if muskrat activity directly influences water quality and if those changes have implications for plant and animal communities. The objective of this study is to investigate the direct influence of muskrats on water chemistry and plant diversity, including a potential role in allowing invasive plant species to gain access to Great Lakes coastal wetland systems. This study will sample paired sites, a muskrat house site and a non-house site, within riverine and lacustrine coastal wetlands during the summer and winter of 2021 to determine the magnitude of effect muskrats have on water quality and plant communities.
Where Art Thou: Lagomorph Populations Abundance in Southeastern Colorado – SRIP
Noah Huth, Nate Bickford
Lagomorph populations across the United States are facing the consequences of habitat loss and fragmentation. The various species of cottontail and jack rabbit are of significant importance to predator species and the diversity of several vegetative species. Habitat fragmentation has increased tremendously over the last century, and prey species that require specific cover are increasingly susceptible to extinction. Both abundant foraging opportunities and escape cover from predators are necessary habitat attributes for lagomorphs. We are investigating the lagomorph population abundance and diversity and quality of vegetation throughout Southeastern Colorado. We are developing models to identify links between vegetation and lagomorph densities. We are conducting lagomorph counts with multiple surveying techniques, and these include vehicle spotlight counts, line-transects, and pellet counts. We are determining population ranges and utilized multiple analytic methods to investigate habitat selection across the second and third order spatial scales. This research will provide key insights into the population dynamics of lagomorph communities, and furthermore, it will strengthen our understanding of biotic and abiotic resources required for a healthy lagomorph population.
Understanding the Effects of Rehabilitation on Eastern Cottontails in Southern Ontario – SRIP
Pauline Kosmal, Sherri Cox, Wendy Pearson, Trevor DeVries, Shoshanah Jacobs
Rehabilitation centres share the common goal of re-integrating wildlife into their natural environments with the ability to reproduce, perform natural behaviours and forage. However, little is known about the success after care within the facility. For this study, eastern cottontails (Sylvilagus floridanus), which are frequently admitted to Ontario rehabilitation centers, will be considered as a model for a high-mortality species mammals. This study proposes the combined use of literature assessments, rehabilitator information sharing, and eastern cottontail fecal composition and dispersal to create evidence-informed best practices. This research begins with a scoping review to determine the current state of available literature, where it comes from, and the study focuses. The next step involves using survey and interview tools to address gaps. The final two studies will assess eastern cottontail health and post-release survival, respectively. Analysis of rehabilitation data would increase the overall validity of practices used and create opportunities for advancement in wildlife care. The collected data can be used to determine whether rehabilitated eastern cottontails are surviving in care and beyond initial release or if rehabilitation practices require revision such as release age, formula type, or implementing the use of soft release. This research will characterize the variation in professional rehabilitation practices across all Canadian wildlife rehabilitation centres. Uniquely, the data collected from survey and interview tools will be cross-referenced with the biological data to complement the research findings. It will address the critical oversights on individual impact of rehabilitators and recognize the importance of information sharing across rehabilitation centres, how resource access can influence decision making, and how this affects eastern cottontail survivability.
Developing Monitoring Protocols for Beavers in Ohio – SRIP
Madeline Kenyon, Viorel Popescu, Katie Dennison
Beavers (Castor canadensis) were extirpated from Ohio by 1830 due to overharvesting from trapping and hunting but have since been reintroduced and recolonized the state. Currently, beavers are trapped for fur, and population expansion and dynamics are being monitored via aerial surveys. While a large amount of data on beaver occupancy and colonies data has been collected since 2013, monitoring beaver populations is done using ad hoc methods on 25 x 25-mile plots that are characterized as low, medium, and high suitability based on the amount of wetland within each plot. The aim of this study is to incorporate new data on beaver lodge locations, aerial survey data and environmental spatial data extracted from GIS to create occupancy and suitability models for beavers in Ohio and inform management. We will use data on beaver colony counts in 50 25×25 mile plots collected between 2013 and 2019 and parameterize models using spatial environmental data such as wetland habitat, land use cover, vegetation type, stream network and human and road as predictors of beaver habitat suitability. The predictions from these models will then be tested against the ad hoc rankings of low, medium and high suitability based on wetland area alone. Thus, this study will effectively correct potential biases in beaver habitat classification by incorporating many sources of data in a predictive model. Based on these predictions, I will be able to create maps that will forecast high suitability habitat for beavers that is still not colonized and assess the expansion of beavers in Ohio. Ultimately, this work can inform the sustainable management of Ohio’s beaver populations and ensure its long-term viability.
The Log Not Taken: Escape Behavior and Path Selection in Woodland Deer Mice – SRIP
Gretchen Andreasen, Michael Cramer
For prey animals like the woodland deer mouse, Peromyscus maniculatus gracilis, escape behavior is important for avoiding predators. This behavior influences how mice select their paths and can depend upon the predator detection risks present in the environment. This study evaluated the paths of 16 adult deer mice in two temporal settings (night and day). During the day, there is a higher risk of visual detection than at night, and we predicted that mice released in this temporal setting would prefer paths with more coverage. At night, the risk of visual detection is decreased. Therefore, we predicted that mice released at this time would prefer paths on quieter substrates, because mice would be more concerned with possible auditory detection. Contrary to these predictions, we found that mice preferred louder substrates in both settings, and there was no significant difference in coverage preference in either setting. Anti-visual detection behavior was observed in the significant difference in path lengths between day (11.846 m ± 4.123) and night (32.375 m ± 7.450), and the number of turns in the path (day 14.000 ± 2.2563; night 34.000 ± 5.435). This suggests that mice are more concerned with visual detection, and there is conflicting evidence of anti-predator behavior in nocturnal mice paths. More intensive behavioral field research is necessary to fully understand the influence of predation-reducing behavior on the path selection of deer mice.
Impact of White-Nose Syndrome and Local Climate on Reproduction of Southeastern Bats – SRIP
Sarah Krueger, Sarah Zirkle, Trevor Walker, Joy O’Keefe, Catherine Haase
Energetic trade-offs between hibernation and reproduction occur in hibernating bat species to ensure pups are born when forage availability is optimal, but little is known about the extent to which bats delay their reproduction as a response to the increased energetic costs of disease, winter duration, and local climate variables. White-nose syndrome (WNS) is an infectious disease that disrupts hibernation behavior, leading to premature exhaustion of fat during hibernation. There is evidence of reproductive shifts in areas where WNS has devastated bat populations, leading to later births, which can be problematic if juveniles lack adequate time to gain fat stores before hibernation. However, current research has yet to assess these changes in response to winter duration or local climate. We compiled capture data from 1988 through 2020 from Kentucky, Tennessee, and Georgia, and used linear mixed effects models to compare effects of WNS, winter duration, and local climate variables on the number of reproductive females for two WNS-susceptible species (tri-colored bat [Perimyotis subflavus] and little brown bat [Myotis lucifugus]) and two species not affected by WNS (big brown bat [Eptesicus fuscus] and red bat [Lasiurus borealis]). We incorporated the effects of WNS in two ways: first as presence and absence of WNS, with presence dictated by year first observed, and second, year since WNS to determine if populations would stabilize after exposure. We suspect that WNS susceptible species would see a decline in the number of reproductive females, with the effect exaggerated by longer winter durations and harsher climate variables. This information is critical to understanding the effects of disease on population growth through impacts on reproductive behavior.
Using Dynamic Occupancy Models to Aid Management of an Imperiled Cottontail – SRIP
Kathryn Bischoff, Tracy Rittenhouse
Conservation planning for rare and declining species is a challenge due to limited and imperfect data. Creating management strategies becomes especially difficult when native species are threatened or inhibited by the presence of an introduced species.  The New England cottontail (Sylvilagus transitionalis) has been the focus of management and conservation efforts for several years because of range contraction and population loss from the decline of early successional forest in New England.  However, the presence of the non-native and introduced eastern cottontail (Sylvilagus floridanus) complicates the potential effectiveness of New England cottontail management actions, with recent research demonstrating eastern cottontails in co-occupied sites can push New England cottontail into the marginal or mid/late-successional habitat.  Using two single-species dynamic occupancy models, this project aims to understand if features of the patch and landscape can allow New England cottontail to successfully live amongst eastern cottontails.  Connecticut cottontail populations have been monitored for several years, providing a robust dataset of presence/absence data for both cottontail species.  The proportion of wetlands, development, managed areas, and shrubland habitat within maximum cottontail dispersal distance of each detection location will be measured using GIS layers. On a smaller scale, characteristics of patches and relationships between patches will be quantified using R packages and used as patch covariates. By understanding how elements of cottontail habitat impact the colonization and extinction of each species separately, we can identify the specific patch and landscape attributes that slow the extinction of New England cottontail while reducing the colonization of eastern cottontail.  This study is intended to inform placement of managed patches within the landscape, locate areas of priority, and identify patch characteristics that are conducive to New England cottontail for effective management.
Are Invasive Cattails Important Drivers of Muskrat Declines in North America? – SRIP
Gregory Melvin, Jeff Bowman, Carrie Sadowski
The muskrat (Ondatra zibethicus) is an important wetland species with significant cultural, economic, and ecological value in North America. Recent studies have confirmed suspicions of widespread population declines. Water level management is known to negatively affect muskrat populations, but the spread of invasive cattails may also play a significant role. An invasive hybrid cattail, Typha x glauca, has been spreading throughout North American wetlands and increasing in abundance. In coastal Lake Ontario wetlands, the proliferation of T. x glauca coincides with the construction of the St. Lawrence Seaway and resulting stable water levels. T. x glauca forms large, dense stands which may be reducing the degree of water-cattail interspersion preferred by muskrats. Population-level effects on muskrats from cattail invasions remain unknown, and a recent shift to a more natural water management regime for Lake Ontario is prompting contemporary assessment of muskrat populations in the region. This study will investigate broad-scale spatial and temporal trends in muskrat densities in relation to T. x glauca and a new water management plan, as well as fine-scale muskrat habitat selection. First, we will compare muskrat house densities across multiple sites with varying levels of water-cattail interspersion and relative abundance of T. x glauca using a combination of aerial imagery and field data. Next, we will use remote cameras to assess muskrat habitat selection in a cattail-dominated marsh with a mosaic of high and low interspersion of cattail and water. Finally, we will compare current muskrat house densities in Lake Ontario coastal wetlands to those observed under the previous water management regime. This study will help determine the significance of cattail invasions on long-term muskrat declines, providing important management implications for muskrats, water, and wetland ecosystems in North America.
Preliminary Findings Indicate That Enzyme-Linked Immunosorbent Assays Likely Underestimate Hantavirus Prevalence in Rodent Communities – SRIP
Jaecy Banther-McConnell, Samuel Goodfellow, Robert Nofchissey, Thanchira Suriyamongkol, Steven Bradfute, Ivana Mali, Manuel Varela
Hantaviruses are zoonotic viruses that can cause two diseases in humans: Hemorrhagic Fever with Renal Syndrome (HFRS; Old World) and Hantavirus Cardiopulmonary Syndrome (HCPS; New World). Several rodents in family Cricetidae are known hantavirus reservoir hosts in North America. These asymptomatic rodents have the ability to shed the virus through their excrement and human infection usually occurs through inhalation of aerosolized viral particles. In the US, New Mexico (NM) is the leading state in the number of HCPS cases. The majority of New Mexican HCPS cases have occurred in northwestern NM, with no reported cases in eastern NM. For this reason, minimal research attention has been given to eastern NM despite confirmed HCPS cases in bordering Texas counties. The objective of our study is to assess hantavirus prevalence in rodent assemblages across eastern NM. We have surveyed 20 sites over 30,000 trap nights and collected blood and lung samples from over 650 rodents, including competent and non-competent hosts. To date, we have tested 522 blood samples for Sin Nombre Virus (SNV) specific antibodies through enzyme-linked immunosorbent assays (ELISA). Twenty-five blood samples tested positive for hantavirus antibodies. We also tested 116 lung samples through RT qPCR using SNV specific and two pan hantavirus primers. For 24 samples, there was amplification for all three primer pairs. Interestingly, only four of those rodents also tested positive for the antibodies. Both laboratory techniques identified previously unreported species as potential hantavirus hosts, one of which has been considered a dilution agent. Our preliminary results indicate that hantaviruses are present in rodent assemblages in eastern New Mexico and can assist us in predicting future HPS outbreaks. Additionally, this study will significantly expand our understanding of hantavirus prevalence and will be used to investigate the amplification and/or dilution effects among rodent communities.
Evaluation of Detection Methods for Semi-Aquatic Mammals in Northeastern Indiana – SRIP
Eleanor Di Girolamo, Geriann Albers, Bruce Kingsbury, Mark Jordan, Scott Bergeson
The American mink (Neovison vison) is a semi-aquatic mammal in the Mustelidae family. Their cryptic nature makes studying mink occupancy difficult. Thus, little is known about their current distribution, especially in Indiana. Environmental DNA (eDNA) has been an effective tool for surveying cryptic species (e.g., Eastern hellbender, Kirtland’s snake, and various carp species). Our objective is to evaluate and compare the efficacy of eDNA and camera trapping as methods for detecting American mink. We sampled 7 bodies of water around Fort Wayne, Indiana that are surrounded by both rural and urban land cover. We collected ten 1L water samples from each site, once a week, for 3 weeks. We filtered 500mL from each sample and stored the filtrate in a -20ºC. eDNA analyses, using quantitative PCR, are still underway We also monitored each body of water with multiple camera traps for a minimum of 5 days prior to collecting the water samples. We will compare the results of the eDNA sampling to the camera trap data to determine if they obtain similar estimates of mink occupancy, if one method is more effective, or if both methods are best used in conjunction. This research will contribute additional information about American mink occupancy in Indiana, as well as insight into the most cost- and time-effective method to survey them. By doing so, this research will provide data that will be used to inform the establishment of a state-wide occupancy survey of American mink.  

Location: Virtual Date: November 5, 2021 Time: 11:00 am - 12:00 pm