Yes, a pellet gun is good. Mine is out of commission. I haven't had time to disassemble it & find the bad part, to see if I can get a replacement.
I've also been using a slingshot, but I've slipped a lot over the years. As a kid, I could hit a wasp nest from 20-30 feet nearly every time, with ordinary rocks. I can't hit a squirrel now at 20 feet with 1/4 or 3/8 steel balls. I can hit all around them, but never a hit. I've lost my touch.
I did get one recently with my junk .22 short revolver (Rohm), but it's too loud to use when neighbors are home & out.