We used to have a group of males that would stand around and wait for our landlords female that was not neutered. I know what you mean when you say the Males stand outside and YELL! That is exactaly what they do, But the noisiest part I found is the actual courting and mating process...They sound like they are killing eachother. After she had a litter we took her to a vet to get her fixed, I think was less than a week after her litter(wasn't very long..) well when we picked her up from her operation the vet notified us that she was already carrying another litter of babies! Either she is a lil skank.. .or they can retain sperm! They aborted the babies (without even asking us) and spayed her. That may be an option for you... If you don't feel bad about it (seeing how overpopulated cats are these days I think it is better than having more unwanted kitties in the world) take her to get her spayed, and if she is pregnant they will take care of it for you. I will also note, and this could have been anything, but less than a year after this, we had taken over care of the cat, since we had been handling all the vet issues... She unfortunatley became sick and passed.