Southern California Western Gray Squirrel Research Project
Visits so far since 01/23/07
The goal of this public participation research project is to map the current distribution of the western gray squirrel, Sciurus griseus, in Los Angeles, Orange, Riverside, San Bernardino, and Ventura Counties in southern California. Establishing a current distribution map will allow for an identification of current habitats that support populations of western gray squirrels. This information will assist in management of viable populations of western gray squirrels as habitats are modified through human activity or as habitats are invaded by populations of introduced fox squirrels, Sciurus niger.
The western gray squirrel is a large tree squirrel that is native to the states of Washington, Oregon, and California. This species, while still being fairly abundant within the state of California, is listed as a threatened species in the state of Washington. This means there is a concern of possible extinction of the species from the state of Washington. The Western gray squirrel is listed as a sensitive species in the state of Oregon, which means it is declining in population size in that state. The species is also listed as a Federal Species of Concern.
In California, western gray squirrels are not as abundant as they were in the past. This decrease in abundance is due to loss of habitat and competition with other species. Development of land for residential and commercial use has decreased the amount of natural habitat available for the species and interaction with the introduced fox squirrel has resulted in the disappearance of gray squirrels from certain areas. You can learn more about fox squirrels in southern California by visiting http://instructional1.calstatela.edu/amuchli/squirrelform.htm.
You can participate in this research project by providing location data for sightings of western gray squirrels. If you sight a squirrel in an area with streets and residences, you can provide the address of the nearest house. If you sight a squirrel in an area away from residential areas you can provide GPS coordinates in decimal format. Please use the submission form at the end of this page to provide your information.
Western gray squirrels look silvery gray on their back and sides while their belly is white. White tips on the gray hairs give them a silvery appearance.

Photo by Allen M. Johnson
Western gray squirrels are active in the daytime (they are diurnal) and they are inactive at night. The best time to see western gray squirrels is in the early morning hours as they retreat to their nests during the hotter portion of the day.
Other species of squirrels in southern California which can be confused with the western gray squirrel include the introduced fox squirrel and the native California ground squirrel. Pictures of the fox squirrel and the California ground squirrel are shown below. The fox squirrel is very brown to reddish brown in color with a yellowish belly. The California ground squirrel is mottled brown with large white patches on the shoulders.
|
|
![]() |
Fox Squirrel California Ground Squirrel
Photo by Weidong Luo Photo by Dr. Brad Hollingsworth
You can help us gather data for the Southern California Western Gray Squirrel Research Project.
The information you provide on the form below will assist us in our project. We thank you for your assistance and we hope that you enjoy seeing the gray squirrels and the fox squirrels in southern California.
Thank You,
Dr. Alan Muchlinski
***SURVEY FORM***