Migratory Ruby-crowned Kinglet. I originally thought they were Orange-crowned Warblers, but further research and a reader tip indicates I may have mis-identified them.
The wing-bars seem to be the tell….
They visit our yard each winter and are extremely elusive in terms of getting a photo. Today there were two of them in the front yard and they seemed oblivious to my presence. So oblivious, one nearly landed on my arm while I was shooting the pictures. Even so, they dart around so quickly and erratically they are not easy to photograph.