This species is a rare but regular late autumn migrant and winter visitor to the coast of California, but Spring records such as this are particularly scarce. It is possible this individual is the same bird seen at the nearby Sharp Park golf course 27 December 2019 documented here. . The pale crown, throat and chest are consistent with the northern race T. m. satrapa breeding from Arizona to northern South America. T. m. occidentalis is a synonym. Note the tail molt with some retained juvenile rectrices and some alternate rectrices still growing in. This is apparently typical of the first prealternate molt in this species (Pyle 1997).
References:
Pyle, P. (1997). Identification Guide to North American Birds, Part I: Columbidae to Ploceidae. Slate Creek Press, Bolinas, CA, USA.
Stouffer, P. C., R. T. Chesser, and A. E. Jahn (2020). Tropical Kingbird (Tyrannus melancholicus), version 1.0. In Birds of the World (S. M. Billerman, Editor). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.trokin.01