We noted back in early March that the Bell's Vireo was starting to appear in Southern California. Well, now we can say that it has arrived in California in large numbers. This bird spends its winters in Mexico and comes northward to the southern United States and midwest. California typically only sees them in the southern part of the state, but they do stretch upward as well. This photo by the always great Glen Tepke was actually snapped in San Francisco's Golden Gate Park. Here's the eBird map from February for the Bell's Vireo, compared to one from yesterday. When one is talking about the Bell's Vireo, one should be mindful of the Endangered Least Bell's Vireo, which tends to occur only in the very southern parts of California.