I found a Semipalmated Sandpiper with a yellow flag on its right leg
(bird's frame of reference) today, in a flooded field in Newtown,
Hamilton County, Ohio, USA.  Unfortunately I could not get close
enough to read any codes.  The field is private property that is
scoped from across a street that borders the property.  Crossing the
street onto the property itself would most likely result in flushing
the birds.
Cheers,
Bill Hull
Cincinnati, OH, USA
http://www.mangoverde.com/
http://www.flickr.com/photos/mangoverde/
http://www.youtube.com/user/mangoverde2