Pigs (Sus scrofa) are native to Eurasia and northern Africa. In the early 1700s Spanish and Russian settlers introduced domestic pigs to California as livestock and many became feral. In the 1920s a Monterey county landowner introduced the European wild boar, a wild subspecies of Sus scrofa into California, which bred with the domestic pigs. The result of these introductions is a wild boar/feral domestic pig hybrid. They have explosive reproductive rates—a sow can have two litters a year and can become pregnant at six months, and disperse rapidly—a boar can travel up to 12 miles a day. Today, feral pigs are now found in 57 of 58 counties in California.

Feral pigs are omnivorous and highly destructive to native habitats and species. The majority of their diet consisting of grasses, forbs, and mast such as shoots, roots, tubers, fruit, and seeds. They also eat many invertebrates and small vertebrates (Seward at al. 2004). Feral pigs prey actively on many vertebrates including herpetofauna, small mammals, birds, and young of larger mammals including deer and livestock (Schley and Roper 2003).

A sounder of pigs can “Rototill” significant acres of land in one night, which can take years to recover. Rooting by pigs not only disturbs the soil physically and destroys plants, but pigs consume vast quantities of acorns, inhibiting regeneration of oak woodland and reducing the food available to the many other species that rely on acorns or oaks (Sweitzer and Van Vuren 2002).

Until 2006, San Diego County remained one of two counties in California that did not have a resident population of non-native wild pigs. Since that time, three or more introductions of pigs resulted in the establishment of several populations of wild pigs that grew and were believed to span the backcountry of San Diego County, threatening species and habitats covered under several San Diego NCCP’s.

In response, NCCP stakeholders and land management agencies initiated a San Diego Feral Pig Removal Program in June of 2014. By that time, it was estimated that the local population was between 250 and 1,000 feral pigs and had spread throughout the county. The USDA APHIS Wildlife Services was chosen to lead the removal effort and a monitoring program to track pig movement and inform the removal effort was lead by San Diego State University (SDSU) and the San Diego Management and Monitoring Program (SDMMP).

The Institute for Ecological Monitoring and Management at SDSU has expertise in ecology, conservation, and applied biostatistics does extensive research and analysis for a number of San Diego NCCP covered species. SDMMP (sdmmp.com) was formed to establish monitoring protocols, design adaptive management strategies, and monitor over 100 species, habitats, threats, and reserve function for the San Diego NCCP. SDMMP is funded by the San Diego Association of Governments at approximately $2 million per year.

Dodging a bullet, the collaborative feral pig removal effort for San Diego has been highly effective thus far.  Monitoring cameras and evidence collected by field researchers indicate that as of December 2017, two pigs are known to persist in the project area and it is estimated that less than ten pigs remain in the county. Monitoring will continue to inform the program goal of countywide eradication.