Graduation Date

Fall 2017

Document Type



Master of Science degree with a major in Natural Resources, option Wildlife

Committee Chair Name

Jeffrey Black

Committee Chair Affiliation

HSU Faculty or Staff

Second Committee Member Name

Micaela Szykman Gunther

Second Committee Member Affiliation

HSU Faculty or Staff

Third Committee Member Name

Barbara Clucas

Third Committee Member Affiliation

HSU Faculty or Staff

Subject Categories



Mobbing is a widespread anti-predator behavior with multifaceted functions. Mobbing behavior has been found to differ with respect to many individual, group, and encounter level factors. To better understand the factors that influence mobbing behavior in wild Steller’s jays (Cyanocitta stelleri), I induced mobbing behavior using 3 predator mounts: a great horned owl (Bubo virginianus), common raven (Corvus corax), and sharp-shinned hawk (Accipiter cooperii). I observed 90 responses to mock predators by 33 color-marked individuals and found that jays varied in their attendance at mobbing trials, their alarm calling behavior, and in their close approaches toward the predator mounts. In general, younger, larger jays, that had low prior site use and did not own the territory they were on, attended mobbing trials for less time and participated in mobbing less often, but closely approached the predator more often and for more time than older, smaller jays, that had high prior site use and owned the territory they were on. By understanding the factors that affect variation in Steller’s jay mobbing behavior, we can begin to study how this variation might relate to the function of mobbing in this species.

Citation Style

Journal of Wildlife Management


Thesis/Project Location