Code:
#dynamic 0x800000
#org @start
lock
faceplayer
msgbox @1 0x6
cry 0x6 0x0
wildbattle 0x6 0x1E 0x8B
fadescreen 0x1
fadescreen 0x0
hidesprite 0x2
setflag 0x200
release
end
#org @1
= CHARIZARD: Raaarrgghh!
Never hacked emerald or did a static encounter but this script I found on this forum should have everything you need. Pretty sure these commands don't change between FR and Emerald.
The two commands you have to use are after wildbattle; hidesprite and setflag. Hidesprite hides the sprite with the person event number in the argument (0x2 here). setflag is then used here to make the sprite with that flag ID
permanently disappear. For the example script to work, the sprite's "person event no" in advance map must be 2, and the sprite's "Person ID" must be 200. You can switch out those values for your birds' sprites, just make sure the script matches what you put on the sprite in advance map.
The fadescreen is not necessary but looks nice.
If you clear that flag in any script later the sprite will reappear.