I feel fortunate to see, and capture, this little beauty. I believe it is a female Ruby-crowned Kinglet. The name derives from the red patch on the male's head. They are described as having that white ring around the eye, with a tiny bill. The female lays such a large number of eggs for such a little bird, usually incubating from 5-9 eggs for 13 or 14 days. They are very active and difficult to catch still long enough for a photo. My Birds of Oregon book says that they are sometimes seen in streamside willows, and that is where I captured this photo, in Delta Ponds.