Black-tailed Prairie Dog Colonies Research Articles

Boom and bust cycles of black-tailed prairie dog populations in the Thunder Basin grassland ecosystem

AbstractBlack-tailed prairie dogs (Cynomys ludovicianus) exhibit boom and bust cycles in landscapes where they are affected by outbreaks of plague caused by the introduced bacterium Yersinia pestis. We examined spatiotemporal dynamics of black-tailed prairie dog colonies in the Thunder Basin National Grassland, Wyoming over a period of 21 years. The colony complex experienced three plague epizootics during that time, and consequently three boom and bust cycles. The entire prairie dog colony complex collapsed over a 1-year period during the first and third epizootics, and over a 3-year period during the second epizootic. The boom and bust cycles were characterized by relatively rapid contractions in total area occupied by prairie dogs during a plague outbreak (e.g., >99% decline from 10,604 ha to 47 ha over 1 year [2017–2018]) followed by much slower recovery times (e.g., an increase from 410 ha to 10,604 ha over 11 years [2006–2017]). Prairie dogs occupied a total of 10,604 ha during at least one survey within the study period, but much of the area was not continuously occupied over time. We found that each of the three plague outbreaks occurred in years with highly connected prairie dog colonies and slightly above-average temperatures and summer precipitation, which were preceded by a dry year. Although plague outbreaks were associated with climatic conditions, we were unable to detect a role of climate in driving colony expansion. Our results illustrate the cyclic and extreme nature of fluctuations in black-tailed prairie dog colony size and distribution in a landscape where plague occurs and illuminate some of the drivers of these cycles. Further, our work shows how introduced diseases can dramatically influence populations of a keystone species, with important consequences for the broader ecological system.

Comparison of Flea Sampling Methods and Yersinia pestis Detection on Prairie Dog Colonies.

Scientists collect fleas (Siphonaptera) to survey for Yersinia pestis, the bacterial agent of plague. When studying fleas parasitizing prairie dogs (Cynomys spp.), two primary methods are used: (1) combing fleas from live-trapped prairie dogs and (2) swabbing fleas from burrows with cloth swabs attached to metal cables. Ideally, burrow swabbing, the cheaper and easier method, would explain flea burdens on prairie dogs and provide reliable information on plague prevalence. In a linear regression analysis of data from 1-month intervals (June-August 2010-2011) on 13 colonies of black-tailed prairie dogs (Cynomys ludovicianus, BTPDs) in New Mexico, flea abundance on swabs explained 0-26% of variation in BTPD flea burdens. In an analysis of data (May-August 2016) from six colonies of BTPDs in Montana, flea abundance on swabs explained 2% of variation in BTPD flea burdens. In an analysis of data from a short-term interval (July 23-27, 2019) on four colonies of BTPDs in Montana, flea abundance on swabs explained 0.1% of variation in BTPD flea burdens. In an analysis of data from 1-week intervals (August-October 2000) on four colonies of white-tailed prairie dogs (Cynomys leucurus, WTPD) in Utah, swabbing data explained 0.1% of variation in WTPD flea burdens. Pools of fleas from two WTPD colonies were tested for Y. pestis by mouse inoculation and isolation; 65% from WTPDs tested positive, whereas 4% from burrows tested positive. Data herein also show that results from burrow swabbing can misrepresent flea species composition and phenology on prairie dogs. Burrow swabbing is useful for some purposes, but limitations should be acknowledged, and accumulated data should be interpreted with caution.

Dialects in the alarm calls of black- tailed prairie dogs (Cynomys ludovicianus): A case of cultural diffusion?

Prairie dogs (Cynomys spp.) produce an alarm call when a predator appears. Gunnison’s prairie dogs (Cynomys gunnisoni) produce calls that vary in spectral structure according to predator type and specific characteristics unique to the individual predator, such as color and shape. These calls vary depending on geographic location and have been characterized as dialects. Black-tailed prairie dogs (Cynomys ludovicianus) also encode information about terrestrial predators in their alarm calls. However, nothing is known about whether there are dialects in these alarm calls, and if so, why these dialects might have arisen. We studied the alarm calls and habitat characteristics of eight different black-tailed prairie dog colonies within the Southwestern USA: Maxwell National Wildlife Refuge, NM, Vermejo Park Ranch, NM, Kiowa National Grasslands, NM, Rita Blanca National Grasslands, TX, and Comanche National Grasslands, CO. An analysis of time and frequency changes in alarm calls showed that colony sites that were located within 30 km each other did not have significant differences in alarm call structure, but sites that were more distant were significantly different from the other sites, consistent with the existence of dialects as well as with genetic models of isolation by distance. The acoustic structure of the alarm calls was not explained by differences in habitat characteristics at each site. A comparison of Squared Euclidian Distances (D2) of alarm calls versus linear distances between sites showed a significant positive correlation, implying that alarm call dialect differences increase the farther one site is from another. This relationship is consistent with a cultural diffusion model of dialects, and is similar to that observed in human dialects.

Drought-mediated changes in black-tailed prairie dog colonies in the Northern Great Plains

Abstract Populations of many mammal species living in grassland ecosystems across North America have been reduced greatly over the past 200 years due to conversion of native prairie to human-related uses. Foremost among these species is the black-tailed prairie dog (Cynomys ludovicianus), populations of which have declined an estimated 98% during that time. In addition to anthropogenic factors including plague, black-tailed prairie dog populations can vary in size in response to grazing by native ungulates, fire, and precipitation. Colonies in the Northern Great Plains have expanded and contracted during dry and wet periods, respectively. Drought reduces vegetation height; tall vegetation is known to limit colony expansion, possibly due to increased predation risk. We used mixed-effects models to analyze data sets of colony areas of black-tailed prairie dogs spanning 16–22 years and 983 total colony counts, from 142 unique colonies at Badlands National Park and Wind Cave National Park, South Dakota, United States, and Scotts Bluff National Monument, Nebraska, United States, to relate areal dynamics of colonies over time to total annual precipitation, drought stress, and plague. We also analyzed the relationship between active-burrow densities and precipitation and drought stress using 7 years of data from 271 colony counts at Badlands National Park. Black-tailed prairie dog colonies expanded in response to drought conditions in all three national parks, with colonies in Wind Cave National Park exhibiting a time-delayed response. In addition, colony area was negatively related to total accumulated precipitation for the preceding 12 months for Scotts Bluff National Monument. Active-burrow density at Badlands National Park decreased in response to drought stress with a time lag of 24–36 months. Plague first was reported at Badlands National Park in 2008 and colony areas decreased dramatically and rapidly during plague epizootic events. Our results support observations that black-tailed prairie dog colonies in the Northern Great Plains expand and contract in response to drought stress and wet weather. Furthermore, our findings provide new insights into the role of climate on a keystone species of conservation importance and demonstrate the value of collecting long-term ecological data.

An invasive disease, sylvatic plague, increases fragmentation of black-tailed prairie dog (Cynomys ludovicianus) colonies.

A disease can be a source of disturbance, causing population declines or extirpations, altering species interactions, and affecting habitat structure. This is particularly relevant for diseases that affect keystone species or ecosystem engineers, leading to potentially cascading effects on ecosystems. We investigated the invasion of a non-native disease, plague, to a keystone species, prairie dogs, and documented the resulting extent of fragmentation and habitat loss in western grasslands. Specifically, we assessed how the arrival of plague in the Conata Basin, South Dakota, United States, affected the size, shape, and aggregation of prairie dog colonies, an animal species known to be highly susceptible to plague. Colonies in the prairie dog complex were mapped every 1 to 3 years from 1993 to 2015. Plague was first confirmed in 2008 and we compared prairie dog complex and colony characteristics before and after the arrival of plague. As expected the colony complex and the patches in colonies became smaller and more fragmented after the arrival of plague; the total area of each colony and the mean area per patch within a colony decreased, the number of patches per colony increased, and mean contiguity of each patch decreased, leading to habitat fragmentation. We demonstrate how an emerging infectious disease can act as a source of disturbance to natural systems and lead to potentially permanent alteration of habitat characteristics. While perhaps not traditionally thought of as a source of ecosystem disturbances, in recent years emerging infectious diseases have shown to be able to have large effects on ecosystems if they affect keystone species.

Black-Tailed Prairie Dog (Cynomys ludovicianus) Reintroduction Can Limit Woody Plant Proliferation in Grasslands

Tree and shrub proliferation has been widespread in grasslands worldwide, and has altered ecosystem function and wildlife habitat. Several causes have been proposed for the woody plant encroachment phenomenon. The widespread eradication of a native keystone herbivore in North American grasslands, the prairie dog (Cynomys spp.), is one potential contributing factor that has received relatively little attention. We hypothesized prairie dogs would have historically suppressed woody plants by creating “browse traps” through their systematic clipping of vegetation. We tested this hypothesis by conducting surveys and experimentally manipulating shrub accessibility via exclosures and artificial saplings on and around recently reestablished black-tailed prairie dog (C. ludovicianus) colonies in southeastern Arizona, USA. Shrubs were common on the nascent colonies (mean ± SE = 132 ± 32.7 plants ha-1), but at substantially reduced densities compared to off colonies (305 ± 94.9 plants ha-1). Among branches placed on colonies to simulate ‘saplings’, 89% were damaged within three days of ‘planting’, whereas those placed off colonies were virtually untouched. This was true for both a deciduous, N2-fixing shrub (velvet mesquite, Prosopis velutina) and an evergreen non-N2-fixing shrub (creosote bush, Larrea tridentata). Prairie dogs on newly established colonies did not extirpate woody plants over the time-frame of our study, but reduced their abundance and suppressed their growth, which would ostensibly prevent them from achieving dominance. Implications for extending the longevity of widely practiced ‘brush management’ grassland restoration treatments are discussed in the context of perceptions of prairie dogs as rangeland pests. Prairie dogs represent an enigma in keystone conservation. Whereas the reintroduction of large or charismatic keystone species (e.g. sea otters [Enhydra lutris]) are conducted to restore critical ecological function, reintroductions of other keystone species, such as gray wolves [Canis lupus] and in our case, prairie dogs, are highly controversial. Our findings suggest reintroductions of this negatively perceived small herbivore could function as a tool to locally suppress woody plant proliferation that is widely regarded as an impediment to livestock production. Accordingly, prairie dogs could promote restoration efforts to re-establish and maintain habitat for grassland endemics while promoting biological diversity and other ecosystem services.

Mountain Plover habitat selection and nest survival in relation to weather variability and spatial attributes of black-tailed prairie dog disturbance

Abstract Habitat loss and altered disturbance regimes have led to declines in many species of grassland and sagebrush birds, including the imperiled Mountain Plover (Charadrius montanus). In certain parts of their range Mountain Plovers rely almost exclusively on black-tailed prairie dog (Cynomys ludovicianus) colonies as nesting habitat. Previous studies have examined Mountain Plover nest and brood survival on prairie dog colonies, but little is known about how colony size and shape influence these vital rates or patterns of habitat selection. We examined how (1) adult habitat utilization, (2) nest-site selection, and (3) nest success responded to a suite of local- and site-level variables on large prairie dog colony complexes in northeastern Wyoming. Abundance of adult Mountain Plovers was highest on points within older, “medium”-sized (100–500 ha) colonies with high cover of annual forbs and bare ground (5.8 birds km−2), but lower on extremely large (>2,000 ha) colonies (2.1 birds km−2). Nest sites were characterized by high proportions of annual forbs and bare ground and low cactus cover and vegetation height. Nest survival was higher for older nests, and nests with lower cactus cover, and decreased with increasing temperatures. Uncertainty was high for models of daily nest survival, potentially because of 2 competing sources of nest failure: nest depredation and nest abandonment or inviability of eggs. Drivers of these 2 sources of nest failure differed, with inclement weather and higher temperatures associated with nest abandonment or egg inviability. We highlight how prairie dogs alter vegetation structure and bare ground heterogeneously across the landscape, and how this in turn influences bird abundance and nest distribution at different temporal and spatial scales. Furthermore, our work reveals how partitioning the causes of nest failure during nest survival analyses enhances understanding of survival rate covariates.

Tree Cover in the Surrounding Landscape Reduces Burrowing Owl (Athene cunicularia) Occupancy of Black-Tailed Prairie Dog Colonies in South Dakota

Burrowing Owl (Athene cunicularia) population declines have led to the owl's designation as a species of conservation concern in South Dakota. Burrowing Owls nest primarily in black-tailed prairie dog (Cynomys ludovicianus) colonies, but a significant proportion of colonies in South Dakota are not occupied by owls. We studied the influence of landscape-level habitat variables on colony selection by Burrowing Owls. We used call-playback surveys to document presence or absence of Burrowing Owls at 613 prairie dog colonies throughout western and central South Dakota. We used a geographic information system to calculate the percent cover of prairie dog colonies, grassland, cropland, and tree canopy in the surrounding landscape at four buffer sizes. We modeled Burrowing Owl occupancy of prairie dog colonies using logistic regression, and ranked models using Akaike's Information Criterion. All competitive models contained a tree-canopy-cover variable. Increasing tree canopy cover within 800 m and 1200 m of colony centers was associated with decreasing likelihood of occupancy by Burrowing Owls. Grassland, cropland, and prairie dog colony cover variables did not influence occupancy by Burrowing Owls, and these variables did not improve model fit or discrimination. In landscapes where the presence of nesting burrows is not a limiting factor, as in central and western South Dakota, Burrowing Owls occupied colonies based on the absence of trees. Trees provide habitat for avian and mammalian predators and reduce the available foraging area for Burrowing Owls around prairie dog colonies. Management for Burrowing Owls should include conserving prairie dog colonies in landscapes with few trees and preventing the establishment of trees near occupied colonies.

Plague-Positive Mouse Fleas on Mice Before Plague Induced Die-Offs in Black-Tailed and White-Tailed Prairie Dogs.

Plague is a lethal zoonotic disease associated with rodents worldwide. In the western United States, plague outbreaks can decimate prairie dog (Cynomys spp.) colonies. However, it is unclear where the causative agent, Yersinia pestis, of this flea-borne disease is maintained between outbreaks, and what triggers plague-induced prairie dog die-offs. Less susceptible rodent hosts, such as mice, could serve to maintain the bacterium, transport infectious fleas across a colony, or introduce the pathogen to other colonies, possibly facilitating an outbreak. Here, we assess the potential role of two short-lived rodent species, North American deer mice (Peromyscus maniculatus) and Northern grasshopper mice (Onychomys leucogaster) in plague dynamics on prairie dog colonies. We live-trapped short-lived rodents and collected their fleas on black-tailed (Cynomys ludovicianus, Montana and South Dakota), white-tailed (Cynomys leucurus, Utah and Wyoming), and Utah prairie dog colonies (Cynomys parvidens, Utah) annually, from 2013 to 2016. Plague outbreaks occurred on colonies of all three species. In all study areas, deer mouse abundance was high the year before plague-induced prairie dog die-offs, but mouse abundance per colony was not predictive of plague die-offs in prairie dogs. We did not detect Y. pestis DNA in mouse fleas during prairie dog die-offs, but in three cases we found it beforehand. On one white-tailed prairie dog colony, we detected Y. pestis positive fleas on one grasshopper mouse and several prairie dogs live-trapped 10 days later, months before visible declines and plague-confirmed mortality of prairie dogs. On one black-tailed prairie dog colony, we detected Y. pestis positive fleas on two deer mice 3 months before evidence of plague was detected in prairie dogs or their fleas and also well before a plague-induced die-off. These observations of plague positive fleas on mice could represent early spillover events of Y. pestis from prairie dogs or an unknown reservoir, or possible movement of infectious fleas by mice.

Trophic Ecology Warrants Multispecies Management in a Grassland Setting: Proposed Species Interactions on Black-tailed Prairie Dog Colonies

On the Ground • Trophic cascades occur when flora and fauna directly and/or indirectly influence co-occurring species populations at different levels of the food chain, and North American temperate grasslands provide an interesting case study to research these relationships. • We briefly define trophic cascades in terrestrial systems and explore the potential for a cascading trophic interaction among grassland-associated swift fox (Vulpes velox), western burrowing owl (Athene cunicularia hypugaea), and mountain plover (Charadrius montanus), three rangeland species of conservation concern, on black-tailed prairie dog (Cynomys ludovicianus) colonies using two US Forest Service data sets. • Historic patterns of occurrence and co-occurrence suggest top-down control governs the spatiotemporal distribution patterns of the three species and may be influenced by habitat fragmentation and management actions. • Managing for interactive, multitrophic communities requires the identification of species interactions and the mechanisms that drive them. • Long-term multispecies occupancy research, combined with hypothesized driving mechanisms and the co-occurrence of associated grassland species, is recommended for addressing these complex interactions moving forward.

Evaluation of Five Pulicides to Suppress Fleas on Black-Tailed Prairie Dogs: Encouraging Long-Term Results with Systemic 0.005% Fipronil.

Plague, a flea-borne disease, hampers efforts to restore populations of black-footed ferrets (Mustela nigripes), which occupy colonies of prairie dogs (Cynomys spp.) in North America. Plague is managed by infusing prairie dog burrows with DeltaDust® 0.05% deltamethrin, a pulicide that kills fleas. Experiments are needed to identify pulicides that can be used in rotation with DeltaDust for integrated plague management. In South Dakota, USA, we tested the efficacy of four pulicide dusts when applied at a rate of 8 g per burrow on colonies of black-tailed prairie dogs (Cynomys ludovicianus): Sevin® 5% carbaryl; Dusta-cide® 6% malathion; Alpine® 0.25% dinotefuran with 95% diatomaceous earth; and Tri-Die® 1% pyrethrum with 40% amorphous silica and 10% piperonyl butoxide. We also tested systemic 0.005% fipronil, which was distributed as ½ cup of laced grain per burrow. We sampled prairie dogs on 3294 occasions and detected 10,041 fleas. Sevin and Dusta-cide suppressed fleas but only for 1 month. Neither Alpine nor Tri-Die had any noticeable, consistent effect on fleas. Fipronil suppressed fleas by 97-100% for 3 months. The residual effect of fipronil persisted for ∼12 months. Efficacy of fipronil seems comparable with DeltaDust, which exhibited a residual effect for ∼10 months in prior studies. Continued research is needed to optimize fipronil treatments for plague management on prairie dog colonies.

Burrow Dusting or Oral Vaccination Prevents Plague-Associated Prairie Dog Colony Collapse

Plague impacts prairie dogs (Cynomys spp.), the endangered black-footed ferret (Mustela nigripes) and other sensitive wildlife species. We compared efficacy of prophylactic treatments (burrow dusting with deltamethrin or oral vaccination with recombinant “sylvatic plague vaccine” [RCN-F1/V307]) to placebo treatment in black-tailed prairie dog (C. ludovicianus) colonies. Between 2013 and 2015, we measured prairie dog apparent survival, burrow activity and flea abundance on triplicate plots (“blocks”) receiving dust, vaccine or placebo treatment. Epizootic plague affected all three blocks but emerged asynchronously. Dust plots had fewer fleas per burrow (P < 0.0001), and prairie dogs captured on dust plots had fewer fleas (P < 0.0001) than those on vaccine or placebo plots. Burrow activity and prairie dog density declined sharply in placebo plots when epizootic plague emerged. Patterns in corresponding dust and vaccine plots were less consistent and appeared strongly influenced by timing of treatment applications relative to plague emergence. Deltamethrin or oral vaccination enhanced apparent survival within two blocks. Applying insecticide or vaccine prior to epizootic emergence blunted effects of plague on prairie dog survival and abundance, thereby preventing colony collapse. Successful plague mitigation will likely entail strategic combined uses of burrow dusting and oral vaccination within large colonies or colony complexes.

Swabbing Prairie Dog Burrows for Fleas That Transmit Yersinia pestis: Influences on Efficiency.

Scientists and health-care professionals sometimes use a swabbing technique to collect fleas from rodent burrows, and later test the fleas for Yersinia pestis, the causative agent of plague. Detection of Y. pestis is enhanced when large pools of fleas are available. The following study investigated factors that might affect the rate at which fleas are collected from burrows in colonies of black-tailed prairie dogs (Cynomys ludovicianus). Data were collected from 13 colonies in New Mexico during 0600-1000 hours, June-August 2010-2011. Fleas were scarce on swabs inserted into burrows that were not actively used by prairie dogs; fleas are presumably suppressed in burrows that are void of hosts and might have begun to collapse due to a lack of maintenance. Fleas were scarce on swabs inserted into burrows with little sunlight entering the tunnel; many species of fleas use changes in light intensity to locate objects, but if light is limited, it might be difficult to locate a swab. Fleas were scarce on swabs inserted to shallow depths underground, especially during hot mornings, and during the hottest portions of mornings; when conditions are hot above ground, ectothermic fleas might migrate into the deep components of burrows, or become less willing to jump onto hosts, making it difficult to collect the fleas with swabs. If the swabbing technique is used to survey for Y. pestis on colonies of black-tailed prairie dogs, investigators might use the results of this study to modify their methods and increase the number of fleas collected.

Kangaroo rat foraging in proximity to a colony of reintroduced black-tailed prairie dogs

Abstract We examined the indirect effects of reintroduced black-tailed prairie dogs (Cynomys ludovicianus) on resident kangaroo rat (Dipodomys) populations. We used the Giving-up Density theory to quantify kangaroo rat foraging on a black-tailed prairie dog colony vs. foraging near the colony edge or in the surrounding native habitat. This approach allowed us to assess the influence of black-tailed prairie dogs on kangaroo rat foraging activity. Our results showed a greater foraging preference off-colony in most seasons. Kangaroo rats visited off-colony feeding trays more frequently and collected a greater mean mass of seed as well. This indicated that kangaroo rats perceived the area off the prairie dog colony as having a lower foraging cost than the on-colony or colony edge locations. Our data suggest that from the perspective of the seed-eating kangaroo rat, the colony is not viewed as high quality habitat. Both prairie dogs and kangaroo rats have been described as keystone modifiers in grassland ecosy...

Factors Influencing Burrowing Owl Abundance in Prairie Dog Colonies on the Southern High Plains of Texas

Large numbers of Western Burrowing Owls (Athene cunicularia hypugaea) nest in black-tailed prairie dog (Cynomys ludovicianus) colonies in the southern high plains of Texas. Because the Western Burrowing Owl is a species of concern with an uncertain future due to widespread extirpation of prairie dogs, we examined the roles of prairie dog colony size, burrow density, proxies of prey availability, and vegetative composition and structure on owl abundance and reproductive rate. The number of nesting Burrowing Owl pairs was positively correlated to colony area (r2 = 0.550, P = 0.006) and to number of prairie dog burrows in a colony (r2 = 0.733, P = 0.0230). Burrowing Owl numbers and reproductive rate (maximum number of young seen per successful pair) were not related to our measures of vegetative composition and structure in prairie dog colonies, nor to indices of prey availability.

Abundance of hantavirus hosts in a landscape with black-tailed prairie dog colonies in northwestern Mexico

In order to assess the influence of habitat type on the abundance and distribution of hantavirus reservoir hosts and on the prevalence of hantavirus antibodies, we compared communities of small mammals among three dominant habitats in northwestern Mexico (grassland with prairie dogs colonies, grassland without prairie dogs colonies and mesquite shrubland). Grassland habitats had a very low abundance of hantavirus reservoir hosts (Peromyscus leucopus and P. maniculatus), whereas mesquite shrubland harbored a significantly higher abundance of reservoir hosts. Seropositive hosts were found in mesquite and grassland without prairie dogs (32% overall seroprevalence), but due to the small sample size of hantavirus hosts in grasslands, we could not compare seroprevalence among habitats. Areas with higher abundance of hantavirus hosts can increase the risk of human infections in other systems; therefore, mesquite shrubland may be the habitat that represents the highest risks for human exposure to hantavirus in this area. Given that the black-tailed prairie dog prevents the expansion of mesquite shrubland into grassland habitats, their colonies may indirectly prevent hantavirus host dispersion and expansion throughout this landscape. Future investigations are needed to further understand potential effects of prairie dog colonies on hantavirus epidemiology.

Avian Use of Black-Tailed Prairie Dog Colonies in Shortgrass Prairie

Downward trends in populations of many grassland bird species are of conservation concern. Declines in black-tailed prairie dog ( Cynomys ludovicianus ) populations result in loss of habitat for birds and other species associated with their colonies. We measured abundance, diversity, and species composition of avian communities on prairie dog colonies and noncolony sites in the Texas Panhandle. More resident species ( P &lt; 0.001) occurred on prairie dog colonies than on noncolony areas whereas, more nearctic-neoptropical migrants ( P = 0.003) and nearctic-temperate migrants ( P &lt; 0.001) occurred on noncolony sites. Total avian abundance was greater ( P &lt; 0.001) on noncolony sites than at prairie dog colonies, and differed by season ( P &lt; 0.001). Barn swallows ( Hirundo rustica ), red-winged blackbirds ( Agelaius phoeniceus ), horned larks ( Eremophila alpestris ), and chipping sparrows ( Spizella passerina ) were more abundant on noncolony sites than on prairie dog colonies. Burrowing owl ( Athene cunicularia ), Cassin’s sparrow ( Peucaea cassinnii ), and lark bunting ( Calamospiza melanocorys ) abundances were greater on prairie dog colonies. Vegetative alterations made by prairie dogs may not influence bird populations as much in these shortgrass prairies as has been reported in mixed-grass prairies.

Eradication of a black-tailed prairie dog (Cynomys ludovicianus Ord, 1815) colony in North Central Florida

Non-native black-tailed prairie dogs (Cynomys ludovicianus Ord, 1815) that had emigrated from a private colony were reported by property owners in rural North Central Florida in 2006. The Florida Fish and Wildlife Conservation Commission and U.S. Department of Agriculture Animal and Plant Health Inspection Service Wildlife Services (WS) initiated an assessment of the population to determine its current distribution and the feasibility of eradication. Multiple surveys, interviews with residents and observations of abandoned burrows confirmed movement of animals as far as 3 km from the source colony. WS personnel conducted an eradication program of the source colony from 23 March through 4 May 2009, primarily using a 0.17-caliber rifle along with cable restraint devices for particularly wary animals. A total of 85 prairie dogs were killed at the site of the source colony and one animal was killed on a separate property. Subsequent surveys from 2009 through 2012 confirmed the eradication was successful. Communication with the owner of the source colony and nearby residents throughout the project was critical to success.

American badgers selectively excavate burrows in areas used by black-footed ferrets: implications for predator avoidance

We evaluated how American badgers (Taxidea taxus) might exert selective pressure on black-footed ferrets (Mustela nigripes) to develop antipredator defenses. In a colony of black-tailed prairie dogs (Cynomys ludovicianus) in South Dakota, badgers concentrated their activities where burrow openings and prairie dogs were abundant, a selective behavior that was exhibited by ferrets in the same colony. Badgers excavated burrows more often when in areas recently used by a ferret, suggesting that badgers hunt ferrets or steal prey from ferrets, or both. We also conducted an analysis of survival studies for ferrets and Siberian polecats (M. eversmanii) released onto prairie dog colonies. This polecat is the ferret’s ecological equivalent but evolved without a digging predator. Badgers accounted for 30.0% of predation on polecats and 5.5% of predation on ferrets. In contrast, both polecats and ferrets have evolutionary experience with canids, providing a plausible explanation for the similar relative impact of coyotes (Canis latrans) on them (65.0% and 67.1% of predation, respectively). We hypothesize that ferrets and badgers coexist because ferrets are superior at exploitation competition and are efficient at avoiding badgers, and badgers are superior at interference competition.

Movements and burrow use by northern grasshopper mice as a possible mechanism of plague spread in prairie dog colonies

Abstract Northern grasshopper mice (Onychomys leucogaster) have been implicated as a potential reservoir for plague, which causes local extinction of black-tailed prairie dog (Cynomys ludovicianus) colonies. To identify mechanisms by which grasshopper mice could facilitate plague spread, we measured burrow use, movements, and flea burdens of mice in colonies in northern Colorado. At the microhabitat scale, powder-tracked mice (n = 41) used both prairie dog mounds and burrows extensively, entering an average of 5.3 burrows per 100 m traveled. Burrow use did not differ between active and inactive mounds, or vary with mouse age, sex, or reproductive status. Radiotracking revealed that mice occupied larger ranges (X = 3.84 ha) than reported off colonies, which we estimated would overlap 12–23 prairie dog coterie territories. Mice also harbored high flea burdens (8.1 fleas/mouse), including fleas associated with prairie dogs, which we attributed to their frequent use of burrows. Our results support the conten...