Sebra
lol, not sure how serious you are but the seagull pics did it for me
But to answer your question, treyarch uses fx for that.
You can plax fx for crows and yes, even seagulls, they are in ra...
Amazing 
This might look small to the other people but its huge for me thanks for this always been wanting to make a lab type map and with this i can do a perfect one