Porcupine Ecology in Oregon

Ecology of North American Porcupines in Oregon

The North American porcupine (Erethizon dorsatum) is the second largest rodent in the U.S. As a generalist herbivore that exhibits seasonally specialized characteristics (e.g., behavior, diet) in harsh environments, it occupies diverse ecosystems throughout much of North America. In Oregon, their distribution includes much of the state east of the Cascades, but only in localized and limited areas west of the Cascades. In some areas, both the distribution and abundance of porcupines have been decreasing during recent decades, with anecdotal evidence supporting decreases in many areas within the western U.S. In fact, monitoring populations of porcupines in the Pacific Northwest seems limited primarily to anecdotal records of mortalities caused by vehicle strikes.

There is very limited contemporary research on porcupines, particularly in Oregon, including studies that described their habitat use, demographics, population dynamics, and seasonal diet. Although the North American porcupine is classified as an Unprotected Mammal in Oregon, ODFW has recently added this species to the list of Species of Greatest Conservation Need in the State Wildlife Action Plan (formerly, Oregon Conservation Strategy) in 2026 due to the lack of ecological knowledge about the species, their putative decrease in abundance, and other factors. The goal of our proposed project is to collect data on key ecological data on porcupines in central Oregon to increase our understanding of the ecological role of this species, and in turn help inform management decisions by ODFW and other agencies. We also expect our proposed project to serve as the foundation and template for expansion of research efforts on populations of North American porcupines in Oregon and potentially other regions within the western U.S.

Our objectives are to:

Identify areas occupied by porcupines in central Oregon through the use of multiple monitoring tools;
Capture, radio-collar, and monitor 15–20 porcupines based on data collected using those monitoring tools;
Assess seasonal space use (e.g., home-range sizes) and resource-selection patterns;
Document movements, including dispersal events by juveniles, when possible;
Evaluate demographic patterns (e.g., survival, cause-specific mortality), including in association with space use and resource selection; and
Collect scat samples to assess seasonal dietary characteristics and limitations.

Our study area includes the Deschutes Watershed (green outline) in central Oregon USA. This area included portions of primarily the Blue Mountains, Columbia Plateau, and East Cascades ecoregions; the Bend, Dalles, and Ochoco ODFW districts; and numerous Conservation Opportunity Areas (colored areas).

Motion-sensing cameras coupled with reported observations in recent years are being used to help locate specific areas inhabited by North American porcupines. Images courtesy of Oregon Department of Fish and Wildlife.

Project Partners