Video clip: https://youtu.be/mILaaHJ8YW0
This species is a rather recent addition to the California avifauna having been first recorded in 1964 along the Colorado River. First nesting was in the 1980's. Birds in Northern California are presumably the smaller western Q. m. nelsoni but the larger more easterly Q. m. monsoni is reported to have reached California in the 1980's. The two apparently form a hybrid zone in the Southern California deserts. This species is currently uncommon in San Mateo County, although they are regularly seen in the parking lot of a shopping center in Daly City, a likely a feeding area for the small breeding colony at the south end of nearby Lake Merced in San Francisco.
References:
Johnson, K. and B. D. Peer (2020). Great-tailed Grackle (Quiscalus mexicanus), version 1.0. In Birds of the World (A. F. Poole and F. B. Gill, Editors). Cornell Lab of Ornithology, Ithaca, NY, USA. https://doi.org/10.2173/bow.grtgra.01
Patten, M. A., G. McCaskie and P. Unitt. (2003). Birds of the Salton Sea: Status, biogeography, and ecology. Berkeley: University of California Press.