Relocation of squirrels to save the burrowing owl...

Despite having cute, fuzzy tails and playful antics, the California ground squirrel has a bad reputation as a pest. But because this species plays a critical role as a grasslands engineer, creating homes for other animals, San Diego Zoo Global scientists are relocating squirrels to aid a species of concern, the burrowing owl.

On Tuesday, Colleen Lenihan, Ph.D., a San Diego Zoo Institute for Conservation Research scientist, led a team of four to check on previously translocated squirrels in Jamul. To date, the Zoo's newest hometown conservation program has relocated more than 350 squirrels to three sites within San Diego County that are thought to be suitable habitat for squirrels and owls.

Together with U.S. Fish and Wildlife Service, San Diego State University, California Department of Fish and Game, San Diego Area Governments and others, the Zoo has hit the ground running. The relocation of the squirrels and observation of existing burrowing owl nesting sites is the first phase of a science-based conservation program. The project aims to create a plan on how to manage local grassland habitat for burrowing owls and other species integral to the ecosystem that can be adopted in other areas where management is needed.

The burrowing owl is currently listed as a species of concern by the U.S. Fish and Wildlife Service, but its population is crashing and may require listing as an endangered species if not assisted. The population has dropped because this species is found only in grasslands, favouring flat ground with low vegetation, which is habitat that is also ideal for development and where invasive plants can be prevalent. In undeveloped areas, habitat destruction does not explain the dwindling numbers of owls, but the elimination of ground squirrels may have made these areas unsuitable as burrowing owl breeding sites.

Because burrowing owls have adapted to human landscapes, and as they can lay up to 11 eggs per clutch, this species has an increased likelihood for successful recovery if an adaptive management plan is created now.

Goals for the burrowing owl conservation program include developing a model that addresses habitat needs, genetic viability and conservation threats such as loss of habitat due to development and invasive species. In this first year, San Diego Zoo Global scientists hope to create suitable habitat that is self-sustaining by restoring a more intact, functional ecosystem.

"The re-establishment of California ground squirrels is a critical component of any long-term recovery plan for burrowing owls and the larger ecosystem because squirrels provide vital resources. Sites with ground squirrel colonies have a greater diversity of reptiles, amphibians, insects and birds than sites where they are absent."

- Colleen Lenihan, Ph.D., San Diego Zoo Institute for Conservation Research

SAN DIEGO ZOO