While I don't have advice on how to avoid this situation, I did have a similar problem with my cat. She freaked out one afternoon after watching a squirrel on the patio. I walked up to pet her, and was severly scratched for my efforts. I went on-line to find out why and discovered this Kitty advice -
"You experienced an episode of Feline Displaced Aggression. This basically means you had a moment of Mistaken Identity. Your nervous system was in gear and you were primed for the attack on your intruder. But you got short circuited when your mom distracted you. The good news is that this kind of aggression in cats is not very likely to recur unless the same situation is in place again. I recommend your mom stay away from you when your tail is twitching and you are concentrating on your sentry duty." http://www.cathosp.com/deartab.html
Your older cat was on the receiving end of all that aggression. Poor kitty.
Good luck with your little soldier.

[ October 18, 2001: Message edited by: Laura ]