Food of Cougars in the Cascade Range of Oregon

Volume 45 Number 1 Article 9

1-31-1985

Food of cougars in the Cascade Range of Oregon

Dale E. Toweill Oregon State University, Corvallis

Chris Maser U.S. Department of the Interior, Bureau of Land Management, Corvallis, Oregon

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Recommended Citation Toweill, Dale E. and Maser, Chris (1985) "Food of cougars in the Cascade Range of Oregon," Great Basin Naturalist: Vol. 45 : No. 1 , Article 9. Available at: https://scholarsarchive.byu.edu/gbn/vol45/iss1/9

This Article is brought to you for free and open access by the Western North American Naturalist Publications at BYU ScholarsArchive. It has been accepted for inclusion in Great Basin Naturalist by an authorized editor of BYU ScholarsArchive. For more information, please contact [email protected], [email protected]. FOOD OF COUGARS IN THE CASCADE RANGE OF OREGON'

Dale E. Toweill- and Chris Maser'

.\nsTi\.\CT.— Animal and nonanimal items were identified in the digestive tracts of 61 cougars (Felis concolor) collected between 1978 and 1984 from the western slopes of the Cascade Range in Oregon. Forty-two (69%) of the cougars were taken bv hunters in Decembei- and January, 18 (30"(i) were killed at other times of the year because of their proximity to livestock, and one animal was illegally killed in November. Black-tailed deer {Odocoilcus Iwmionu'i columbi(inus) was the most common prey item, although domestic sheep {Ovis ciries), porcupines (Ercthizon dorsatitni). and a variety of small mammals were also recorded. Masticated grass was the most common nonanimal item.

Tlie cougar was placed under jurisdiction November and confiscated by Oregon State of the Oregon State Game Commission in Police was also examined. Successful hunters 1967 because of a suspected decline in num- were required to present their cougars to bers in the 1950s and early 1960s (Oregon personnel of the Oregon Department of Fish State Game Commission 1967). Prior to 1967, and Wildlife within 48 hours, at which time tlie cougar had been subjected to the bounty biological data were collected and ownership system established by the Oregon Territorial of the pelt was validated. Additional cougars, Government in 1843. The bounty system was killed to protect livestock (primarily domes- repealed by the Oregon Legislature in 1961 tic sheep), were obtained throughout the (Kebbe 1961), but the cougar was not pro- year. tected until it was declared a game animal in Sex, weight, and physical measurements

1967. It was then protected until 1971, ex- were recorded for each animal either by per- cept for individuals that were killing sonnel of the Oregon Department of Fish and livestock. Wildlife or by us. Digestive tracts and repro- The first controlled hunt for cougars in ductive organs were removed, labeled, and Oregon took place in 1971; 13 were killed. frozen for later analysis. Each complete di- Information on food habits from those 13 ani- gestive tract was examined as three separate mals (3 from the Cascade Range) and from 12 elements: stomach, small intestine, and colon. taken in 1972 (none from the Cascade Range) Because some animals were eviscerated in was reported by Toweill and Meslow (1977). the field by hunters, many of whom brought

The purpose of this paper is to present data in only stomachs, more stomachs than colons on foods of cougars from the Cascade Range were available for analysis. Weight of stom- of Oregon and to compare these data with ach contents was recorded to the nearest other data from Oregon (Maser and Rohwe- gram. Endoparasites were also preserved. der 1983, Toweill and Meslow 1977) and Complete digestive tracts normally repre- elsewhere. sented at least two meals: one in the stomach and one in the colon, with elements from both often found in the small intestine (Maser Methods and Rohweder 1983). Items from stomachs and from colons were recorded separately. Most of the animals examined during this Nonanimal items, particularly fragments of study were taken legally by hunters during vegetation, were identified to provide insight the annual controlled season in December about the habitats in which meals were and January; one cougar illegally killed in ingested.

'This is i i paper dedicated to the memory of Ronald Rohweder, an of the Oregon Departn , who helped

n cougars of Oregon. Ron was electrocuted 1 July 19S4. -Oregon Cooperative Wildlife Research Unit, Department of Fisheries and Wildlife, Oregon State University, Corvallis, Oregon 97.3.31. 'U.S. Department of the Interior. Bureau of Land .Management. Forestry Sciences Laboratory, 3200 Jefferson Way, Corvallis, Oregon 97.331

77 Great Basin Naturalist Vol. 45, No. 1

Results and Discussion Absence of Roosevelt elk {Cervus elaphus roosevelti) in the diet of cougars from the Digestive tracts of 61 cougars containing Cascade Range is puzzling. Despite their items were examined. Information, con- food size, elk are commonly reported in the diet sidered to represent 115 separate meals, was of cougars where ranges of the two species obtained from 61 stomach samples and 54 co- overlap (Ackerman et al. 1984, Hornocker samples. lon 1970, Maser and Rohweder 1983, Robinette All cougars examined in this study were et al. 1959, Toweill and Meslow 1977). from the western slopes of the Cas- collected Roosevelt elk are relatively common Range in Oregon between 1978 and cade throughout Douglas and Lane counties, al- 40 (66%) from Douglas County, 19 1984, though they are most often found at eleva- from Lane Covmty, and 1 each from (13%) tions above 600 m (2000 ft) and away from Ciury and Hood River counties. Because of human habitations. We suspect that the lack himt unit boimdaries and because animals of elk in the diet of these cougars was a result taken to control livestock predation were of the small sample size and low elevations at killed near human habitations, all cougars which the cats were taken. were taken at elevations below approx- Depredation of domestic sheep by cougars imately 600 m (2000 ft). occurred all year at low frequency but Cougars taken throughout the year were seemed most common during spring. All oc- examined, although most were taken during currences of domestic sheep in our sample the December-January controlled season. came from cougars killed because of live- Numbers of animals in this sample by month stock damage. The high frequency of occur- killed were as follows: January— 14, March— rence of sheep in the diet of these cougars re- 6, April-3, May-1, June-1, July-2, Sep- sults from the bias introduced by the tember— 4, October— 1, November— 2, and inclusion of cougars killed as a result of live- December— 27. Data were recorded as legal stock depredations. Our data indicate that hmiter kills (42) and others (19). these cougars had usually fed on sheep for at The sex ratio of cougars in our sample was least two consecutive meals. essentially even, 33 males and 28 females. Of Porcupines were recorded in the cougar these, 20 males and 22 females were taken diet with some regularity, and many of the January period, and 13 during the December- cougar carcasses examined showed evidence 6 females were taken at other males and of contact with porcupines in the form of times of the year. embedded quills. The importance of porcu- of stomach contents ranged from Weight pines in the cougar diet has been noted by less than 1 g (traces of hair) to 3.97 kg (9 lbs). Maser and Rohweder (1983) and Young and food item most Black-tailed deer was the Goldman (1964). Deer, porcupines, and grass commonly found in cougars in winter. The have been the most commonly reported dominance of deer in the diet seems a con- ^staples of the cougar diet (Dixon 1982). stant throughout North America, as is evi- The domestic dog {Canis f(uniUaris) found denced by studies conducted in Oregon (Ma- in the stomach of one cougar may represent ser and Rohweder 1983, Towcill and Meslow feeding on carrion. Fly larvae, found among 1977), Washington (Schwartz 1943 in Young clumps of dog hair, indicated that the dog and Goldman 1964), Idaho (Hornocker 1970), had l)een dead several hours before it was California (Dixon 1925), Utah and Nevada consumed by the cougar. (Robinette et al. 1959), Utah (Ackerman et al. Other animals found in the diet of cougars 1984), Arizona and New Mexico (Hibben during this study included mountain beaver 1937), British Columbia (Spalding and Les- {Aplodontia rufa), muskrat {Ondatra zihethi- owski 1971), and throughout the western cus), beaver {Castor canadensis), northern fly- United States (Sperry in Young and Goldman ing squirrel {Claucomijs sahrinus), dusky- 1964). Hippoboscid flies {Lipoptena deprcssa footed woodrat {\cotoma fiiseipes), Trow- pacified), a common ectoparasite of black- bridge shrew {Sorex trowhridii,ei), and hare tailed deer, were recovered from the stom- {Lepus sp.) and may represent opportunistic

achs of four cougars. feeding (Table 1). Such small mammals have January 1985 TowEiLL, Maser: Oregon Cougar Diet 79 also been found in other studies of cougar were associated with plant remains from pon- food habits but usually total less than 10% of derosa pine {Pinus ponderosa), vine maple the diet by frequency of occurrence and con- {Acer circinatum), western redcedar {Thuja siderably less in terms of relative biomass plicata), Oregon grape {Berberis nervosa), and consumed. Exceptions have been noted, how- fern {Polystichum sp.). Douglas-fir needles ever, in Arizona (Hibben 1937) and southern were also commonly found in association Utah (Ackerman et al. 1984). with food of cougars killed other than during We assumed that fish bones, found in the December and January (24% of stomach sam- stomach of one cougar reportedly caught in a ples and 63% of colon samples). Several plant leg-hold trap, represented trap bait since species characteristic of dry, open canopy only skull bones were found. Further, the vegetation types, not recorded from cougars bones were associated with litter (Douglas-fir taken during winter, were found in cougars {Pseudotsuga menziesii) needles, twigs, peb- collected at other times of the year: oak bles, and soil) typical of ground cover within {Querciis garryana), snowbrush ceanothus a closed-forest stand. {Ceanothus velutinus), and Pacific poison oak Masticated green grass was found in many {Rhus diversiloba). of the digestive tracts (Table 1), often in Soil, pebbles, and dry wood, evidence of a large amounts. Although of negligible food cougar having cleaned up a kill, were also value (evidenced by its resistance to diges- found. tion), such grass may have served to purge some of the tapeworms commonly found in Conclusion cougar intestinal tracts. We have observed, in the course of field work, recently passed scats Black-tailed deer, porcupines, and grass consisting almost entirely of masticated grass are staples of a cougar's diet in the Cascade with entwined tapeworms. Range of Oregon, as elsewhere in North Vegetation associated with food items sug- America. Cougars prey on domestic sheep gested that cougars fed most commonly when available and may take a number of among closed-forest habitats during the win- species of smaller mammals (and perhaps car- ter. Needles of Douglas-fir were found in rion) as available. Data suggest that most 62% of the stomachs and 89% of the colons of feeding by cougars was done in closed-cano- cougars killed in December and January and py vegetation types during winter and that

Table 1. Items identified from dii^estive traets of 61 couii;iiis collected from the .estern Cascade Range of Oregon. Data presented as number and frequency (in parentheses) of occurrence. Great Basin Naturalist Vol. 45, No. 1

Dixon, 1925. Food predilections of predator\ and fur- more open types may be used at other times J. liearing mammals. Mammal. 6:34-46. of the year. J. Dixon. K. R. 1982. Mountain lion, Fclis concolor. Pages in 711-727 J. A. Chapman and G. A. Feldhamer, Acknowledgments eds.. Wild mammals of North America. Johns We thank Oregon Department of Fish and Hopkins Univ. Press, Baltimore. HiBBEN, F. C. 19-37. A preliminary study of the moun- Wildhfe personnel who helped collect cougar tain lion (Felis ore^onensis sp.). Univ. Xeu Mexi- viscera: R. Anglin, R. Bartels, L. Conn, B. co Bull. 318. 59 pp. Greer, C. Smith, H. Sturgis, and R. HoiiNofKER, 1970. analysis of mountain Hon Ferry, J. M. G. An of the Idaho Depart- predation upon mule deer and elk in tiie Idaho Werner. J. Beecham Primitive .Area. Wildl. Monogr. 21. 39 ment of Fish and Game; P. Ebert and F. pp. Kebbe, C. 1961. Bounties. Oregon State Game Conim. Newton of the Oregon Department of Fish Bull. 16:3, 6-7. and Wildlife, Portland; D. Grayson, Depart- Maser, C, and R. Rohweder. 1983. Winter food habits ment of Anthropology, University of Wash- of cougars from northeastern Oregon. Great Ba- ington, Seattle; and Z. Maser, Department of sin Nat. 43:425-428. Orec;on State Game Com.mission. 1967. C^ougar. Ore- Forest Science, Oregon State University, gon State Game Comm. Bull. 22. Corvallis, read improved the manuscript. and L., S. Robinette, W. J. Gashwiler, and O. W. Morris. V. Bissell, U.S. Department of the Interior, 1959. Food habits of the cougar in Utah and Ne- vada. Wildl. 23:261-272. Bureau of Land Management, Forestry Sci- J. Mgt. Spaldinc. D. AND LE.SOWSKI. 1971. Winter food of ences Laboratory, Corvallis, Oregon, typed J., J.

the cougar in south-central British Columbia. |. the various drafts. Wildl. Mgt. .35:378-381.

TowEiLL, D. E., and E. C. Meslow . 1977. Food habits Literature Cited of in Wildl. .Mgt. 41:576-.578. cougars Oregon. J. ACKERMAN, B. B., F. G. LiNDZEY, AM) T. P. HeMKEH. Young, S. P., and E. A. Goldman. 1964. The pinna, )9S4. food habits in southern Utah. mysterious cat. Dover Publ., Inc., Cougar J. American New Wildl. M-'t. 48:147-155. York. 358 pp.