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Western Wildlife 4:17–28, 2017: The North American Porcupine (Erethizon dorsatum) is one of the most widely distributed mammals in North America, but recent reports have suggested declines in parts of its range in the West. In California, we know little about porcupines’ historical or current status; maps of porcupine distribution conflict considerably. Nevertheless, the species is of interest to natural resource managers. For much of the 1900s, foresters and others primarily treated porcupines as pests because of the undesirable damage they inflict by feeding on trees and gnawing on manmade items in search of salt. More recently, porcupines have been recognized for their role as engineers, contributing important structure and diversity to forest ecosystems, and as prey for the imperiled Fisher (Pekania pennanti). We collected records of porcupine occurrence in the northern half of California since the beginning of the twentieth century, relying on government and private databases, reports from the public, and other sources. These records confirm porcupine distribution in most major regions and habitat types across northern California, in contrast to many published range maps, and most closely resemble the range map based on projections of suitable habitat developed by the California Wildlife Habitat Relationships System (CWHR). We are unable to offer deeper insight into trends of abundance and possible changes in distribution because these records are likely spatiotemporally correlated with observer effort. This work is a first step in what must be a broader statewide effort, and we encourage further research on the distribution, abundance, and ecology of porcupines in California.

The data provided here consists of 363 unique records of porcupine locations in northern California spanning the years 1908 to 2016. Records were obtained from a participant science project (; internal California Department of Fish & Wildlife records; the California Roadkill Observation System (CROS); internal U.S. Forest Service Records; a study by former HSU Wildlife professor Charles Yocom; iNaturalist; and the Global Biodiversity Information Facility. The second tab includes descriptions of each column of the data, and additional information is available in the (forthcoming) publication.

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