I work for the Land Trust for Santa Barbara and am a regular at the Carpinteria Salt Marsh. I believe I saw a Belding's Savannah Sparrow this morning. I described the bird in my eBird list, which can be found here: https://ebird.org/checklist/S168049638
Let me know your thoughts! From what I understand, the Carpinteria Salt Marsh is one of only areas in the county that have historically hosted this species. Given the time, location and filed marks, I believe it could very well a Belding's.