Just gotta live close to a cat colony.

My last kitty came up on my porch outta nowhere and meowed at me till I loved her. That neighborhood had a feral cat thing going on though.

The last time I had kittens their mom (a neighborhood stray) stashed them under my car. Getting the sharp, squirming lil tykes out of the engine block in Texas summer heat was a memorable experience.

It is rare! These rescues came to us through a friend of a friend in the southern USA (Los Angeles, i think), and wended their way over here in BC Canada. I think in warmer climates you'll see it more.

Does your area have catch, spat/neuter, and release programs for strays?

Usually you get surprise kittens when either someone's unfixed animal gets out and gets pregnant/gets another cat pregnant, or when kittens are dumped because some people aren't good, or unfixed strays get pregnant and have babies.

Some areas may have predators that would deter cats (humans, coyotes, large snakes, alligators, crocodiles, puma/mountain lions etc). Some areas aren't hospitable (weather wise) to strays.