Invasion, Damage, and Control Options for Eastern Fox Squirrels

Abstract

Fox squirrels are an emerging urban, suburban, and agricultural vertebrate pest in California. They cause a diversity of damage to vegetation and property. Multiple introductions of fox squirrels into California have led to a rapid expansion of their range in the state. Fox squirrels at the University of California, Davis increased from none to an estimated 1,609 between 2001 and 2009. Damage due to the dense population of fox squirrels is increasing. There are several population control options available, but social considerations may limit the viable options to non-lethal methods. This paper provides an overview of the impacts of the introduced fox squirrel in California and on the University of California, Davis campus.

Efficacy and health effects of a wildlife immunocontraceptive vaccine on fox squirrels

“…McCleery () suggested that urban fox squirrel populations may grow more rapidly than rural ones (McCleery ). Some urban populations in California are expanding rapidly (King , Krause et al ), and have displaced native western gray squirrels in at least 1 urban park (Muchlinski et al ). The fox squirrels we studied exhibited annual proportions of reproductively active females (0.78) within the range (0.10–0.83) reported for rural populations.…”

“…Fox squirrels are now abundant in many urban and suburban areas in California, and isolated populations reside in Oregon and Washington. Their distribution was expanding at a rate of about 7 km/year near Los Angeles (King ) and approximately 3 km/year in Davis, California (Krause et al ).…”

“…They may depredate gardens and orchard trees (Salmon et al ) and raid backyard bird feeders, and their gnawing may cause extensive damage, including killing tree limbs and damaging wooden and plastic structures (Krause et al ). Fox squirrel range expansion throughout the western United States could lead to widespread damage to agricultural crops such as nuts, avocados, and citrus (Salmon et al ), damage to facility structures (e.g., sprinkler heads, motor vehicles, electrical wiring; Krause et al ), and displacement of the native western gray squirrel ( S. griseus ; Muchlinski et al ). Feasible methods for controlling fox squirrel populations vary by location.…”

Behavioral effects of an immunocontraceptive vaccine on eastern fox squirrels

“…The fox squirrel is native to the eastern United States but has been introduced to the western United States over the last century (Byrne ); it has since become abundant in many urban and suburban areas. Fox squirrels occur throughout much of California, with isolated populations in Oregon and Washington, and their distribution is expanding (King , Krause et al ). They depredate a large variety of garden plants and orchard trees (Salmon et al ) and raid backyard bird feeders, and their gnawing causes extensive damage, including killing tree limbs and damaging wood and plastic structures (Krause et al ).…”

“…Fox squirrels occur throughout much of California, with isolated populations in Oregon and Washington, and their distribution is expanding (King , Krause et al ). They depredate a large variety of garden plants and orchard trees (Salmon et al ) and raid backyard bird feeders, and their gnawing causes extensive damage, including killing tree limbs and damaging wood and plastic structures (Krause et al ). Fox squirrel range expansion throughout the western United States could lead to widespread damage to agricultural crops such as nuts, avocados, and citrus (Salmon et al ), damage to facility structures (e.g., sprinkler heads, motor vehicles, electrical wiring; Krause et al ), and displacement of the native western gray squirrel ( S. griseus ; Muchlinski et al ).…”