Seeking advice on stray cat situation

Hello! I am hoping for some advice from people who have more experience than me in dealing with stray cats. I would love to know what others would do in the situation I'm in now. About a week ago, I discovered a female cat with four kittens living in the back porch of an abandoned house on my street. I called various animal rescue organizations, but no one was available to help. The largest animal rescue organization told me that I could rent live traps from them, if I wanted to try and catch the cats myself and bring them to the shelter (it is a shelter that will work to rehabilitate feral animals). This is what I decided to do.

However, the kittens were very, very fast. The mother and babies would scatter in all different directions immediately upon seeing me. I hated the idea of having to, basically, trap the family members one by one and take them in one at a time to the shelter, at least while the kittens were still little. I decided to start feeding the mother until the kittens were independent of her, at which point I thought I'd feel less guilty about catching them and breaking up the family.

However, after 2 days of leaving food and water on the porch, I stopped seeing the kittens altogether. I've talked with a neighbor, and she hasn't seen them either. I do see the mother, however, coming around to eat the food that I leave, but she never stays on the porch for more than a few minutes. It's been about 3 or 4 days of just seeing the mother.

I am tempted to go ahead and trap the mother and take her to the shelter, but I am not sure what's going on with the kitten situation. Some of my questions:

(1) Do you think something harmed the kittens? I got worried that perhaps I attracted a raccoon or fox by leaving food out.

(2) Do you think the mother moved the kittens off the porch, because I was coming around so much?

(3) If the kittens are still alive, and hanging out somewhere else, then when is an ok time to trap the mother and take her away? I can't get a good look at the babies--they are not tiny kittens, more like maybe "medium" kittens, but not leggy-looking adolescent kittens, if that make sense. They are also, like I said, extremely mobile. I estimate them at 4 weeks or even older. Does that sound right?

I guess my basic question is, what would you do in this situation? Trap the mother now? Feed her for a little while longer and look for signs of the kittens? Other options? Any advice is appreciated!

One more thing-- I guess I should add

(4) This is not technically a no-kill shelter, however it is the only shelter accepting new animals. If a cat cannot be rehabilitated, they may put it to sleep. Hence, I am also considering the option of having the mother fixed and releasing her back in the neighborhood. I have no idea if that's the right thing to do or not. I see her sometimes staring at me and licking her lips, when she sees me coming to bring the food. After only a couple of days, she doesn't run entirely away, but just runs a short distance and then stops to look at me. I have a feeling that she used to be someone's pet, and that she can be rehabilitated. But I'm just not sure. If anyone has advice about how to tell a "feral" cat from a stressed-out, abandoned stray, please let me know that too. 

My guess is, she moved them elsewhere.

You cant just trap her, they would be defenceless and perish.   Although, if enough desperate, you may try with spaying her, and releasle her after 24 hours.

If you wait a little, she will probably bring them to your place when they got somewhat older.  You are her food source, and somewhat friendly - according  to her.

TNR IS an option here, yes, as she is used  to living outside.   Talk with them, they perhaps agree.

This is a lot like the situation I had at work.  When I first spotted the mom and kittens, I put food nearby.  The next day, the kittens were gone.  I guessed at the time that they were maybe 2 months old.  Over the next 2 months, I only saw the kittens 3 or 4 times when she brought them to eat with her.  Once I didn't see them for 2 weeks.  I was sure they had frozen to death or been eaten.  Eventually she moved them back to the abandoned truck where I had first seen them and I made plans to trap them.  So it's not unusual for the mother to be very wary of you and move the kittens to safety.  

if they are just 4 weeks or so, I wouldn't trap the mother yet.  I would just continue to feed her and build her trust.  She will eventually feel ok about the kittens being around you.  Then you can work on trapping them.  Good luck!

If you can, though, start feeding mom in a humane trap. Tie it open so it won't spring and place it on level ground. She will get used to eating in the trap and it will be so much easier to get her when the time comes.

I am thinking that if it is possible to set up a crate in the area, you can try putting the food inside the open crate for the kittens. Once mom is trapped, they will be hungry and perhaps less wary. When the time comes to trap them, tie a length of heavy twine to the door, loop it through the top of the crate and put the food in the crate at the back. Back off a safe distance, holding the twine.

When the kittens are inside eating, pull the twine and close the door quietly. You will need a second person to run secure the door, although with kittens, they may not realize they can push it open.

I've trapped a few litters like this and a couple of moms, too!

During her recovery period, it will be possible for someone to determine if she has the potential to be a pet. If not, would you consider letting her back out and continuing to feed her as the neighborhood cat (if that's allowable or possible)?

In any case, thank you for helping her!

Thanks everyone! Based on this advice, I'll just wait and see for now. I'll keep feeding the mother and try to figure out if the kittens are still around. Thanks for the tip about putting the food inside the humane trap, to get her used to going inside--I will definitely do that.