Hi
I recently began to play with these files, and your post has been great help to me so thank you :)
Here are my guesses about animal flocks :
CREATE_FLOCK( flockID, "x,y" , "x,y" , p1 , p2 , townID)
Flock ID : self explained
"x,y" : location, often it's the same thing written twice
p1 ...