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 by hunters in December and January, 18 (30%) 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 (Odocoileus hemionus columbianus) was the most common prey item, although domestic sheep (Ovis airies), porcupines (Erethizon dorsatum), and a variety of small mammals were also recorded. Masticated grass was the most common nonanimal item.
Toweill, Dale E. and Maser, Chris
"Food of cougars in the Cascade Range of Oregon,"
Great Basin Naturalist: Vol. 45
, Article 9.
Available at: http://scholarsarchive.byu.edu/gbn/vol45/iss1/9