Catalina Island News

Adopt a Species: Catalina California Ground Squirrel

2010-12-13
Catalina Island Conservancy

The Catalina California ground squirrel (Spermophilus beecheyi nesioticus) is endemic (exclusively native) to Catalina. It's a unique sub-species of its mainland counterpart. Slightly larger and more robust than mainland California ground squirrels, it is identified by its darker coat with less distinct shoulder patches. Catalina is the only Channel Island with a ground squirrel species and because ground squirrels are diurnal (active during the day) they are easily visible to Island visitors. The scientific name, beecheyi, was bestowed upon the animal by its original describer in honor of the able and science-minded Commander of the Blossom, Captain F. W. Beechey.

The Catalina California ground squirrel is eight to 10 inches tall when sitting upright, approximately 17 to 19 inches in total length including its tail and weighs 10 to 26 ounces. They may live as long as six years in captivity, but average 3 to 4 years in the wild.

California ground squirrels are most active during the day. They may become lethargic for periods of time when food is scarce and temperatures are extreme. The timing of inactivity varies greatly with individuals, populations, weather, and habitat.

Cover and protection is provided by burrows excavated in loose soils, often on sloping ground near rocky areas or under trees or logs. The burrow system may be elaborate, with six to 20 entrances. The tunnel lengths average 35 feet, and range from three to 138 feet. There are three types of burrows. Male burrows are simple, and are usually dug at the outskirts of the colony. The long, complex nest burrows are occupied by females with young. Long, multi-branched colonial burrows are used by both sexes and the young after leaving the nest burrow.

Catalina California ground squirrels are common along roadsides and in grassland habitats. Open terrain offering a clear view of potential predators is preferable, while nearby rocks, logs, and fences are often used as lookouts.

The ground squirrel is listed as the Island's largest native herbivore with a diet stems and leaves of grasses forbs, and trees, seeds, nuts, acorns, fruits, bulbs, and fungi. They may be more accurately documented as omnivores as they may also eat some insects, bird eggs, and carrion.

A population estimate based on capture-recapture success has not taken place on Catalina. The Catalina California ground squirrel is commonly seen throughout the Island and is considered very abundant, especially during years of above average rainfall.

Peak mating activity occurs March through June with gestation of only one month. The Catalina ground squirrel litter ranges between three and 15 young per litter. Females usually produce only one litter per year, but have been known to produce two litters per year on occasion. Young are weaned at about 55 days and are full-grown in 7 to 8 months.

Catalina ground squirrels live a relatively sheltered life on the Island, however, one of their main threats are motor vehicles. Building their burrows on the berm of roads, they are often seen crossing the road back and forth, which puts them in harm's way. Speed limits on the Island roads are designed to help keep road fatalities for all Island animals to a minimum. Also, ground squirrels, especially the young, can fall prey to Island foxes and feral cats. 

Through the Conservancy's new Adopt a Species program, you can play a leading role in wildlife protection and management on Catalina Island. Choose a "symbolic adoption" from among four of Catalina's iconic and endemic species including the Catalina California quail; the federally endangered, endemic Catalina Island fox; the endemic Catalina Island ground squirrel; and the iconic American bison, introduced to the Island in 1924.

Starting at just $100, you can partner with Conservancy wildlife biologists to protect these and other Island species and help them continue to thrive. For more information, visit: catalinaconservancy.org and click on Adopt a Species on the home page.