Mercy Air has many bases in California. Here is a start so that maybe you can add this to the Wiki and as we get more confirmed base numbers and helicopter call signs, we can add it. I messaged Mercy Air to get a full list.
Mercy Air 1: Rancho Cucamonga
Mercy Air 2: Victorville
Mercy Air 3:
Mercy Air 4: Anaheim
Mercy Air 5: San Diego
Mercy Air 6:
Mercy Air 7:
Mercy Air 18: Thermal
Mercy Air 27: Brawley
Mercy Air H285: Big Bear (With BBFD)
Anyone can add information to the wiki