This source was an extra on Iron Man 2, and she has also provided info before. Well now she has moved to Thor. Her name is Redd, from SHH forums. She has revealed a casting call, I guess for Background extras for Thor. Check it Out:
"auditions for background -
6 ft tall, military look
must be available from January 21st to March 8th
Must be okay with birds on set (Raven birds)"
MarvelFreshman: Just in case you didn't know, Raven birds were very much a part of Norse Muthology. Odin had 2 birds named Hugin and Munin, who everyday would send messages back to Odin from Earth. If this is the case, Kenneth Branagh is really taking every little peice of mythology, and putting it in Thor. Awesome