Warblers and gulls are definitely ID weak spots for me. I saw this little dude in my garden a couple of days and I think I know what it is, but I want your input - please. He pretty much split his time catching bugs in the mid section of trees as well as pretty close to the ground. Tail pumping was a regular feature of the bird's behavior. The weather was lousy and I couldn't get very close to the little guy so your ID guess may be pretty hard to make.
Found this little Ruby Crowned Kinglet zooming around the yard and I managed to capture his crown which I've never managed before. If you ever see a tiny birding acting like its on speed you have a pretty good shot at a Kinglet.