If you trap them and take them to the shelter, they might be put down since they're feral. So if they're not in any danger where they are, nobody is complaining about them, and you don't have homes for them already lined up, I'd leave them there.
What you can do though is trap them and get them fixed, then release them back where they came from. Otherwise, they will start to multiply and you'll start to have a problem on your hands. Check with your local shelter. There may be a local group who will help with the trapping and expense. If you're lucky, you might even live in a municipality that has a trap-neuter-release program for ferals and all you have to do is make the call.
Thank you for taking care of the strays. If everyone did what you're doing, we may not have such a problem with strays in this country.