I spent this lovely warm autumn morning with WRPerry at Blue Mash testing out the rental lens.  Most of the birds we saw were very high in the trees, and quite challenging to shoot.  I saw this little one, but couldn't tell what it was.  I switched the camera to APS-C and the lens to full zoom which would be 900 mm (35 mm equivalent), to discover it was a little titmouse.  In addition, this has also been considerably cropped.  This little guy was really quite lost against the blue sky and seemed to look better in B&W.