i've taken some nice sized ground squirrels, large blacktail jack rabbits and large rats with various air rifles over the years.

i made a very 'lucky' shot on a ground squirrel a while back with my .20 beeman R1 and took a good sized dog squirrel at a measured 124 yards; smack dab in the middle of the chest with a silver jet...lites out...

In answer to your question: feral house cat at close range; he was in a Havahart trap. Gun in question was a Crosman 760.

As to taking deer with a .22 rimfire....illegal in most states, but not everywhere!; check your state regs....and it is illegal in my home state (MI).

As for shooting Canada geese with an airgun: highly illegal and a violation of Federal law.....doesn't matter when or where or the circumstances......Waterfowl are protected by Federal law, and the only legal means of 'taking' them is with a shotgun or bow....no single projectile firearms! (and that includes airguns).

a warthog. one shot right in the eye lol

It's not big, but big fun.
 

I've been shooting the carpenter bees that are trying to drill into my house. I can peg them when they sit on the house with just pumping my crossman one or two times without hurting the house. The best is when the hover around and I shoot them out of the air. Now that is fun.

useta shoot squirrels and rabbits with my bb gun, never owned a pellet rifle, I do know that they are making elk capable air rifles now (.50 cal) and also doves and canada geese are federaly regulated migratory birds, it is a federal offense to shoot either with a rifle no matter how big of nuisance they are.
RR

i once rolled a ground squirrel at a measured 125 yds (ranged it with my range finder) with my .20 beeman R1 (gas piston)...they're tough little buggers that are as common as rocks here where i live.

Brought down a TROPHY KATYDID with one shot to the vitals and a follow up shot to the neck, dropped him in his tracks. As I recall that was with my RED RYDER BB RIFLE at the age of 8....Still pretty proud of that...Not sure if that was what you are looking for here but Hey, it got me hooked on hunting!

;)

The dreaded California Saber Tooth Ground Squirrel.He jumped me from behind AND after a 10 minute wresteling match I pulled the trigger at 7 inches.I made it HE DIDN'T!:D

Big old cottontail and squirrel, all taken while chargeing me.

Shot a couple of squirrels and 1 bunny rabbit and one overly aggressive mouse with my crossman 760.

One Red Fox, A large male raccoon, a nasty old feral tom cat with a Crossman Titan in 22 cal. and numerous skunks with a Benjamin 397.
The raccoon was the toughest by far.