A few of the kittens were so young that they hadn't been taught to fear humans yet, so I was able to just scoop them up and carry them to my house. Others had to be trapped.
Over the last few years, the owner of the property where the colony's located actually has been able to trap every single cat (close to 100) and take them in the traps to the vet for spaying and neutering. After that, he brings them home and releases them back into the colony. It became difficult as the process continued because he kept trapping the same cats over and over. Some cats are more intelligent than others.
The vet notches the altered cat's ear so that the spayed or neutered ones are recognizable and don't have to undergo the procedure more than once.
Here's a view of some of the colony cats coming out to eat. Four of the five in the second photo were trapped for me. The pictures were taken 6 years ago. They have to be enlarged to see all of the cats. I just noticed that four of my other kittens are in the first photo, so only one stayed out of the public eye that day.