Per the Cornell website: "The most abundant grebe in the world, the Eared Grebe breeds in shallow wetlands in western North America. It occurs in greatest numbers on Mono Lake and the Great Salt Lake in fall, where it doubles its weight in preparation for a nonstop flight to its wintering grounds in the southwestern United States and Mexico."
Hard to believe as we only get a handful each year in NC. However, in California I can corroborate the statement. In fact, this picture is from Tijuana Slough National Wildlife Refuge, San Diego, CA.