Recently I found a flock of juncos in San Diego County that contained several forms: Oregon, Slate-colored, Cassiar, and Gray-headed. If I looked longer I may have been able to find Pink-sided, too, to complete all the forms expected in the county. The Oregon form is a resident of the San Diego mountains and a common winter visitor throughout the county. The other forms mentioned above are numerically rare, but regular annually in winter.
I was able to successfully photograph the Oregon, Slate-colored, and Gray-headed forms on a recent morning visit to Oak Hill Memorial Park Cemetery in Escondido. I was not able to get a photo of the Cassiar Junco that was also present. It is a disputed form, some think it a hybrid between Oregon and Slate-colored, others disagree. [See: Not a Slate-colored Junco! The Cassiar Junco.]