well i shoot a lot of ground squirrels with my 223 and about 100 yards or so but its up in the condor zone so its lead free. i use 36g bullet and theirs still meat left. its kind of fun to wait then all of a sudden theirs 5 or 6 running all over then they are gone again for a while. lots of waiting with the ground squirrels. id have to look it up but tree squirrels are a different thing with a season and they are closed in different parts of the state im pretty sure.
added:
§307. Tree Squirrels.
Tree squirrels may be taken only as follows:
(a) General Season and Areas:
The general season in the counties of Alameda, Alpine, Amador, Butte, Calaveras, Colusa, Contra Costa, Del Norte, El Dorado, Fresno, Glenn, Humboldt, Kings, Lake, Lassen, Madera, Marin, Mariposa, Mendocino, Merced, Modoc, Monterey, Napa, Nevada, Placer, Plumas, Sacramento, San Benito, San Luis Obispo, San Joaquin, San Mateo, Santa Clara, Santa Cruz, Shasta, Sierra, Siskiyou, Solano, Sonoma, Stanislaus, Sutter, Tehama, Trinity, Tulare, Tuolumne, Yolo, Yuba, and that portion of Kern County lying east of Interstate 5 shall open on the second Saturday in September extending through the last Sunday in January.
(b) Archery and Falconry Tree Squirrel Season and Area: Tree squirrels may be taken with bow and arrow or raptors only during the general tree squirrel season and as follows:
(1) The season in the counties of Alpine, Amador, Butte, Calaveras, Del Norte, El Dorado, Fresno, Glenn, Humboldt, Lake, Lassen, Madera, Marin, Mariposa, Modoc, Napa, Nevada, Placer, Plumas, Shasta, Sierra, Siskiyou, Solano, Sonoma, Sutter, Tehama, Trinity, Tulare, Tuolumne, and Yuba; and that portion of Kern County lying east of Interstate 5 shall open on the first Saturday in August extending through the day before the general tree squirrel season.
(c) Bag and Possession Limit: Four squirrels per day, four in possession.
(d) Except as provided herein, tree squirrels may not be taken at any time in the balance of the state.
Amendment of subsections (a)(1), (b)(1) and Note, and repealer of subsection (b)(2) filed 6-23-93; operative 6-23-93.