CorrosivE

I'm quite new the RMXP and have purchased it a few days ago. I am using Mr.Mo's ABS and I can't quite seem to make it to where this crow gives +1 feather variable when it dies. I know it can give the item "Feather" but I have something planned on how to utilize this variable. If that was confusing, I'm basically asking how do you set an enemy that you kill, in Mr.Mo's ABS, to add a variable after it dies? This is what I tried and it didn't work: