why do stray cats cry at night

Another major stress in the life of a stray cat is the cycle of pregnancy and litters of cute (yet homeless and totally helpless) kittens. Most stray and feral cats are not neutered or spayed, and the day-to-day existence of stray female cats is often full of the hardships of pregnancy and bearing litter upon litter of offspring.

If you hear a stray cat crying outside, she may be calling out to a kitten that she cannot find, either because someone took him away or there was an unfortunate situation, such as a car accident.
It depends on the vocabulary they're using.

Night id prowling time. They're talking to each other, not to us. Though, what I hear outside is not "baby cries". More like screaming. I think it translates as, "This is MY turf! GET OUT!!! " A female in heat, or a male looking for a female in heat will tend to wail and whine.

My first spring in this house I had a male cat come around "courting" my (fixed! ) female cat, "singing opera" under my windows. Cats don't generally meow at each other. They have a vocabulary trills, chirps, and "fightin' words", but they save the meows for us humans because they have discovered we don't pay attention if they don't.

They seem to be very smart about figuring out what will get our attention best, whether it's a meow, or knocking something off a shelf.

My first cat, Tiro, learned to speak Human very well. One time he wanted to go out and went to the back door while I was in the kitchen. We had a conversation. "NGOW! " "No. You can't go out right now. " "Ngow? " "I said NO! "mrph. " And he walked away. No translation needed.