IIRC in BSL its both hands, thumb and 1st and 2nd finger held as claw . what I'm less sure of is teh position, could be hands held up in front of shoulders- think heraldic eagle OR hands close togetherin front of chest - think bird on perch. Lip speaking Eagle at same time for clarity.
I don;t have it in my book dictonary and my CD rom one won;t work on this machine.
www.learnbsl.org/ has an online dictonary I don;t have the plug ins for.
Signstation have one too, that you have to register for.