Squirrel Species Mapping

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California Tree Squirrels

Download the App

Photo by Alan Muchlinski
Photo by Alan Muchlinski

Have you seen me?

Participate in a real scientific research project that will map tree squirrels throughout California!

Why help?

Two of California’s four day active tree squirrel species are native to the state while the other two species have been introduced over the past 130 years. You can participate in a real scientific research project that will map the current distribution of squirrels throughout California to determine where an introduced species may negatively impact native species.


Just download the app on your Android phone, or visit California Tree Squirrels on Facebook.
The iPhone app is coming soon!

Or email us the species, date observed, and location observed (GPS coordinates OR street address) at californiatreesquirrels@gmail.com


The Two Native Species
Western Gray Squirrel

Western Gray Squirrel

Sciurus griseus

White fur on the abdomen, gray fur on sides and back. Tail is longer than body, very bushy with white-tipped hairs.


Douglas Squirrel

Douglas Squirrel

Tamiasciurus douglasii

Fur on abdomen is light to dark orange, grayish-brown fur on sides and back, found in coniferous (pine) forests.

The Two Introduced Species
Eastern Fox Squirrel

Eastern Fox Squirrel

Sciurus niger

Orange to rust colored fur on abdomen, reddish-brown colored fur on sides, back, and tail.


Eastern Gray Closer

Eastern Gray Squirrel

Sciurus carolinensis

Color Variant 1: White fur on the abdomen, light gray to rust colored fur on the sides and back, tail is light gray with rust coloration and hairs have white tips.

Color Variant 2: Black fur all over animal.

Similar Species

Remember that tree squirrels are found in trees.  Don’t confuse them with ground squirrels or chipmunk!


California ground squirrel

California ground squirrels are approximately the same size as tree squirrels, but have a more rounded topline, and often have a white area along the back behind the shoulders.  Their bodies are 9-11 inches long, with tails adding 5-9 more inches.


California ground squirrel
Spermophilus beechyi


Golden-mantled ground squirrel

Golden-mantled ground squirrels are similar in size to the California ground squirrel.  However, they have a more golden color and stripes along the sides of their bodies.  Tree squirrels do not have stripes.


Golden mantled ground squirrel
Spermophilus lateralis



Chipmunks are smaller than squirrels, at 4-7 inches long, with a 3-5 inch tail.  They have stripes that run from their bodies to their faces, unlike the Golden-mantled ground squirrel, whose stripes end before the face.


Tamias spp.



How to Report Sightings- It’s easy!

1. Flip through the photos of the squirrels in your app to identify the species you see.

2. Click “Saw it!”

3. If you are out of the cell coverage area your phone will still record your GPS coordinates. Just click “Send Saved Sightings” from the upper right drop down menu when you return to the coverage area to submit your sightings.


Download the app here: California Tree Squirrel Android App

Download a reference sheet here:  California Tree Squirrel Poster