Food Habits of Recolonizing Cougars in the Dakotas: Prey Obtained from Prairie and Agricultural Habitats

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1 Am. Midl. Nat. 161:69 75 Food Habits of Recolonizing Cougars in the Dakotas: Prey Obtained from Prairie and Agricultural Habitats DANIEL J. THOMPSON 1 Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings DOROTHY M. FECSKE North Dakota Game and Fish Department, Bismarck JONATHAN A. JENKS Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings AND ANGELA R. JARDING Department of Wildlife and Fisheries Sciences, South Dakota State University, Brookings ABSTRACT. Food habits of cougars (Puma concolor) in North America have been documented for western populations in the United States, Canada and Mexico. Most studies assessed diets of cougars occupying typical habitats, and within established populations. We evaluated food habits of cougars in prairie and agricultural landscapes in the Dakotas (regions that had been devoid of the species for roughly a century) located well outside of known resident populations. We obtained stomach and gastrointestinal (GI) tracts from 14 cougars (10 male; 4 female) from , and evaluated contents via frequency of occurrence (%) of various prey items. Deer (Odocoileus spp.) had the highest frequency of occurrence (50.0%). Other native mammalian prey included jackrabbit (Lepus townsendii, L. californicus), porcupine (Erethizon dorsatum), beaver (Castor canadensis), badger (Taxidea taxus), mink (Mustela vison) and rodent species (e.g., vole). No domestic livestock species were documented as part of the cougar diet in the Dakotas, although remains of domestic housecat (Felis silvestris) were found in GI tracts of two animals. Based on our results, cougars occupying non-typical, newly recolonized habitats were successfully adapting predation techniques for capture of natural and newly confronted prey species. The wide range of prey encountered suggested that prey was being obtained opportunistically in prairie and agricultural landscapes of the Dakotas. INTRODUCTION Cougars (Puma concolor) are obligate carnivores that consume deer-sized prey throughout their range in the western hemisphere (Logan and Sweanor, 2000). As such, how cougars meet their dietary needs via regional differences in prey availability, are of interest in understanding the ecology of this large predator. Cougar food habits have been documented in the western United States and Canada (Robinette et al., 1959; Spalding and Lesoski, 1971; Toweill and Meslow, 1977; Anderson, 1983; Ackerman et al., 1984; Koehler and Hornocker, 1991), the south/southwestern United States (Cashman et al., 1992; Cunningham et al., 1999; Harveson et al., 2000; Logan and Sweanor, 2001), Mexico (Nunez, 2000; Rosas-Rosas et al., 2003) and in southern Florida (Maehr et al., 1990). Although regional differences occur, ungulates, such as mule deer (Odocoileus hemionus), 1 Corresponding author: Telephone: ; FAX: ; daniel.thompson@ sdstate.edu 69

2 70 THE AMERICAN MIDLAND NATURALIST 161(1) white-tailed deer (O. virginianus), elk (Cervus elaphus) and in certain regions bighorn sheep (Ovis canadensis), comprise the primary prey in cougar diets in North America. Much of the information available on cougar food habits and prey availability has been obtained from cougars occupying typical habitats, and within established populations. However, expansion of some western populations during the past 20 y has contributed to the reestablishment of populations in areas where cougars had been extirpated for up to 100 y (Logan and Sweanor, 2000; Cougar Network, 2007; Fecske, 2003; Thompson and Jenks, 2005; North Dakota Game and Fish Department, 2006, 2007). Moreover, verified sightings of the animal have been documented well outside of recently established populations. As cougars recolonize former ranges, it is essential to document prey items encountered while they are navigating new habitats. Our main objective was to document food habits of cougars located outside of the current range and distribution of documented breeding populations in North and South Dakota. Currently, cougars dispersing from the Black Hills of South Dakota and the Little Missouri Badlands of North Dakota are occupying what would be considered atypical cougar habitat (prairies and agricultural lands). Due to large-scale ranching and agricultural presence in these states, we also wanted to document the extent that domestic and livestock species occur in cougar diets. STUDY AREA The Black Hills of western South Dakota and eastern Wyoming has a viable and expanding cougar population (Fig. 1; Fecske, 2003; Thompson and Jenks, 2005). A newly established resident cougar population also occurs in the Little Missouri River Badlands region of western North Dakota (North Dakota Game and Fish Department, 2006, 2007). Subadult cougars have been documented leaving the Black Hills population, and while dispersing, travel through the prairie and agricultural ecosystems that characterize lands in the central and eastern Dakotas (Thompson and Jenks, 2005). Based on historic records, these lands apparently have been devoid of cougars for decades (Logan and Sweanor, 2000). Moreover, the species was never considered common on these landscapes (Young, 1946; Bailey, 1926). Primary land use/land cover classes in South Dakota, outside of the Black Hills, included grasslands (38.15%), agriculture (34.23%) and pasture/idle grass (15.62%) (Smith et al., 2002). In North Dakota, excluding the Little Missouri Badlands Region, more land has been converted to agriculture and cropland use (44.04%) than in South Dakota, whereas grasslands (27.88%) and alfalfa/hayland (13.59%) comprise less acreage (Hagen et al., 2005). Available ungulate prey species in the Dakotas included: mule deer, white-tailed deer, bighorn sheep, pronghorn (Antilocapra americana) and elk. In addition, many mid to small mammalian and avian species occur in this region (Higgins et al., 1994; Peterson, 1995). The distribution of mule deer decreases towards the eastern region of the study area, with relatively few resident populations occurring east of the Missouri River (Higgins et al., 2000). Domestic livestock (primarily cattle, sheep and horses) also represent potential prey items for cougars in the Dakotas. METHODS Diets of cougars were documented by evaluating stomach and gastrointestinal (GI) tract contents of individuals inhabiting prairie and agricultural regions. Stomachs and GI tracts were obtained from cougar carcasses made available through harvest, legal removal or natural mortality, collected by South Dakota Department of Game, Fish and Parks and North Dakota Game and Fish Department personnel. Cougars were necropsied at South

3 2009 THOMPSON ET AL.: COUGAR RECOLONIZING 71 FIG. 1. Study area consisting of North and South Dakota excluding the Black Hills and Little Missouri Badlands Regions, along with locations of cougars obtained for dietary analyses Dakota State University, Brookings or North Dakota Game and Fish Department facilities, Bismarck. Carcasses were aged based on tooth wear and pelage description (Anderson and Lindzey, 2000), sex determined and body measurements taken, along with a general assessment of condition based on fat level indices (subcutaneous, mesentery, heart and kidney fat). For all

4 72 THE AMERICAN MIDLAND NATURALIST 161(1) TABLE 1. Stomach and gastrointestinal (GI) tract contents of Dakota cougars, ID Age Cause of Death Stomach/GI Tract Contents F y Harvest Beaver, rodent, PPQ* F2 3 y Vehicle Trace amount of deer hair F y Vehicle Deer, PPQ* F y Legal Kill White-tailed jackrabbit, rodent, PPQ* M y Harvest Deer, vegetation, PPQ* M y Legal Kill Domestic housecat, PPQ* M y Vehicle Deer, porcupine (in stomach), vegetation, PPQ* M y Legal Kill Deer M5 2 y Legal Kill Badger, mink, deer, PPQ* M6 2 y Harvest Deer, porcupine (in stomach) M y Illegal Kill Vegetation, PPQ* M y Removal Domestic housecat, PPQ* M9 3 y Electrocution Empty, PPQ* M y Incidental Snare Empty, PPQ* * Cougar carcass contained prevalence of porcupine quills imbedded in the flesh at time of necropsy. carcasses, we diligently evaluated the dermis on front legs, chest, neck and facial region for the presence of porcupine (Erethizon dorsatum) quills: presence of quills was used as an index to predation attempts on this species. Stomach and GI tracts from North Dakota cougars were sent to South Dakota State University for analysis; all samples were used to document food habits using frequency of occurrence of various prey items. All identifiable objects were classified to species using presence of major bones and microscopic analysis of hair follicles (Moore et al., 1974). These data were used to calculate frequency of occurrence (%) of prey items of cougars. Because of the landscape level approach of our study, we did not attempt to document prey availability or resource/prey selection. RESULTS A total of 14 cougar carcasses (4 female and 10 male) was obtained for analysis from the study area from Cougars ranged from y of age and averaged 2.42 y of age. Of the 14 animals evaluated, five had more than one prey species in stomach and intestinal tracts (Table 1). Three cougars had empty stomachs, and a fourth stomach contained only trace amounts of deer (Odocoileus spp.) hair, however no cougars appeared to be in poor condition. Deer (mule and white-tailed) had the highest frequency of occurrence (50.0%; n 5 7) in cougar diets, followed by other mammalian species (i.e., beaver (Castor canadensis), porcupine, badger (Taxidea taxus), jackrabbit (Lepus townsendii), mink (Mustela vison) and rodents; 42.86%, (Table 2). Two cougars consumed domestic housecat (Felis silvestris). The majority of carcasses (85.7%) had porcupine quills present in the dermis layer (n 5 12) in addition to the stomach/intestinal tract (n 5 2). Several (n 5 3) stomachs contained trace amounts of vegetation. We did not document domestic livestock species in diets of cougars obtained from prairie and agricultural landscapes of the Dakotas. DISCUSSION Although deer represented a large portion (50%) of cougar diets in our study, the frequency of occurrence was generally lower than levels found in western cougar

5 2009 THOMPSON ET AL.: COUGAR RECOLONIZING 73 TABLE 2. Frequency of occurrence (%) of prey species in diet of Dakota cougars, Prey Species N Frequency of Occurrence (%) Odocoileus spp Medium size mammals* Small mammals** Rodentia spp Domestic cat Empty Vegetation * Porcupine (n 5 2), badger (n 5 1), and beaver (n 5 1) ** Mink (n 5 1) and jackrabbit (n 5 1) populations associated with forested and mountainous terrain (64% summer, 77% winter - Robinette et al., 1959; 57% - Spalding and Lesoski, 1971; 81% - Ackerman et al., 1984; 70% deer and elk - Koehler and Hornocker, 1991). In addition, most studies of cougars in western North America note the presence of elk in diets (Spalding and Lesoski, 1971; Anderson, 1983; Ackerman et al., 1984; Koehler and Hornocker, 1991; Anderson and Lindzey, 2003). Similar frequencies of deer prevalence to our study were found in southeast Arizona (Cunningham et al., 1999), although domestic calves provided a significant portion (34%) of the diet, along with deer (48%) and javelina (Tayassu tajacu; 17%). When combining deer prevalence with domestic livestock prey and other ungulate species (i.e., elk, pronghorn, Ovis spp.), no studies have noted #50% frequencies of deer or similar/ larger size prey items in cougar diets. We realize that many studies report dietary information using different techniques, which may contribute to the variation among studies of cougar diets. Several medium sized mammals (porcupine, badger and beaver), along with small mammal species (jackrabbit, housecat, mink and rodents) were encountered in the diet of cougars suggesting that individuals passing through or occupying prairie/agricultural habitats are opportunistic in their choice of prey. The large variety of documented prey suggests that cougars reoccupying historical habitat had the ability to obtain prey to meet metabolic and energetic needs despite atypical terrain and inexperience with these prey items. Cougars are a stalk and ambush predator (Robinette et al., 1959) generally associated with some type of cover; allowing them to reach a close proximity to prey before attempting an ambush. The variety of prey species and lower abundance of large ungulates in diets of cougars occupying prairie/agricultural habitats may be facilitated by the fact that with reduced cover (i.e., lack of forested habitat) cougars may seek out smaller species that would be easier to capture and utilize as prey. Although a few animals had empty stomachs, none of the carcasses evaluated showed signs of stress or emaciation due to poor condition from lack of available prey in the diet. Although porcupine did not have a high frequency of occurrence in the stomach and intestinal tracts of Dakota cougars (14.3%), there was a high prevalence of porcupine quills (85.7%) found in cougar carcasses, suggesting they represent an important prey item for cougars in the region. Porcupines would represent an easy prey source, and have been documented in most cougar dietary studies (Anderson, 1983). It is possible porcupines represent a relevant prey species in areas where ungulates and other primary prey species are in lower abundance, or where preferential stalking cover is not available.

6 74 THE AMERICAN MIDLAND NATURALIST 161(1) Although domestic felines were documented as a portion of cougar diet, domestic livestock species (i.e., cattle, sheep, horses) were not consumed despite their relatively high abundance throughout the Dakotas. It is possible that livestock operations were avoided by cougars because of husbandry techniques and an association with humans. Despite the absence of domestic species in diets of cougars, anecdotal reports have confirmed domestic livestock kills in the Dakotas. Nevertheless, our results indicate that kills of domestic species likely represent rare events when cougars traverse prairie and agriculture terrain. These large domestic species may be avoided due to inexperience capturing these potential prey items. Our low sample size did not allow us to make strong inferences about preferential food habits of cougars reoccupying the prairies of North America. The lack of a resident population further exacerbates the problem of gaining additional data due to low density of cougars in this landscape. Nevertheless, our results suggest that cougars are able to adapt to new habitat types to obtain prey while they move through historical ranges. Acknowledgments. Our study was funded by Federal Aid to Wildlife Restoration Fund Project W-75-R (Study No. 7594) administered by the South Dakota Department of Game, Fish and Parks (SDGFP), in addition to funds received from Safari Club International. We thank personnel from SDGFP and NDGF Departments for assistance collecting carcasses for necropsy and transport of carcasses. We thank C. Penner from NDGF for developing the map figure. We thank hunters for allowing evaluation of carcasses obtained from hunting for this study in North and South Dakota. We thank A. M. Neils, S. Thomson, E. S. Lorenzen, K. L. Schuler and T. J. Zimmerman for assistance during necropsies. We thank E. S. Lorenzen for assistance identifying guard hairs microscopically. K. L. Schuler and T. Grovenburg reviewed earlier drafts of our manuscript and provided helpful comments. LITERATURE CITED ACKERMAN, B. B., F. G. LINDZEY AND T. P. HEMKER Cougar food habits in southern Utah. J. Wildl. Manage., 48: ANDERSON, A. E A critical review of literature on puma (Felis concolor). Special Report No. 54. Colorado Division of Wildlife, Fort Collins, Colorado. ANDERSON, C. R., JR. AND F. G. LINDZEY A guide to estimating cougar age classes. Wyoming Cooperative Fish and Wildlife Research Unit, Laramie, Wyoming, U.S.A. AND Estimating cougar predation rates from GPS location clusters. J. Wildl. Manage., 67: BAILEY, V A biological survey of North Dakota. North American Fauna. No. 49. CASHMAN, J. L., M. PEIRCE AND P. R. KRAUSMAN Diets of mountain lions in southwestern Arizona. Southwestern Natur., 37: COUGAR NETWORK-USING SCIENCE TO UNDERSTAND COUGAR ECOLOGY. [On-line]. 2007, Available at CUNNINGHAM, S. C., C. R. GUSTAVSON AND W. B. BALLARD Diet selection of mountain lions in southeastern Arizona. J. Range Manage., 52: FECSKE, D. M Distribution and abundance of American martens and cougars in the Black Hills of South Dakota and Wyoming. Dissertation, South Dakota State University, Brookings, USA. HAGEN, S. K., P. T. ISAKSON AND S. R. DYKE North Dakota Comprehensive Wildlife Conservation Strategy, North Dakota Game and Fish Department, Bismarck, North Dakota. 454 p. HARVESON, L. A., M. E. TEWES, N.J.SILVY AND J. RUTLEDGE Prey use by mountain lions in southern Texas. Southwestern Natur, 45: HIGGINS, K. F., E. D. STUKEL, J. M. GOULET AND D. C. BACKLUND Wild mammals of South Dakota. South Dakota Department of Game, Fish and Parks, Pierre, South Dakota, USA. KOEHLER, G. M. AND M. G. HORNOCKER Seasonal resource use among mountain lions, bobcats, and coyotes. J. Mammal., 72:

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