I've seen them before, reported by others, but have no idea what they mean.
Have you tried leaving BYC, clearing your cache and trying again? There is a troubleshooting article linked in my sig line. Firefox or Chrome rather than Windows are recommended, if that's possible for you.
In IE, R-click on one of the `birds' and at the bottom of the list of options that appear should be `Properties'. Copy the address (URL) and post it up. R-click on several and see if the same, or different, URL's appear.