After Texas, Florida, and Alabama, California has the highest recorded numbers of wild pigs in the country. Feral pigs are found in 56 of California’s 58 counties, and the population is estimated to be between 200,000 and 1 million.
The total U.S. wild pig population is estimated to be over 5 million.
The range of wild pigs across California appears to be increasing. Preliminary results from analysis of pig harvest (R. Sweitzer, UC Berkeley, unpublished data) show that pigs extended their range in California by more than 7,000 square miles between 1992 and 2004.
Wild pigs can highly alter the landscape. Underground bulbs and insects compose a significant portion of their diet, and they root up the soil to access these food sources (Barrett 1978). This feeding behavior, compounded by their abundance throughout California, means that the animals are causing varying degrees of damage to ecosystems across the state. Where high density populations have emerged, they have significantly damaged protected lands and agricultural resources (Sweitzer et al. 2000).
Wild pigs consume most any small to medium sized plant or animal in their path, including salamanders, frogs, fish, turtles, eggs and chicks of ground-nesting birds, white-tailed deer fawns, and newborn livestock (Seward, 2004). They make no exceptions for threatened or endangered species. They are particularly destructive in riparian zones, areas that millions of dollars have been spent to conserve and restore, where their intensive rooting and wallowing behavior destroys critical habitat.
Pigs also threaten livestock by competing for food sources and potentially transmitting diseases (Choquenot, McIlroy, & Korn 1996). While disease transmission from pigs has not been documented on Tejon Ranch, the pigs are causing important, although yet to be quantified, ecological damage. As such, better management of the population is critical to preserving the fragile ecosystems on the ranch, as well as the various economic interests of the Tejon Ranch Company.
Unlike most other states, California classifies wild pigs as a big game species instead of a pest species. Comprehensive management plans that work within the legal framework of the state are very rare, and there is a need for cost effective strategies on private lands and protected public lands (Sweitzer et al 2000). Indices of abundance and spatial distribution as well as management options developed by this project may be extrapolated and used as a model for managing wild pigs on public and private lands throughout California and the U.S.