Jazzcat - ok, here is a nutty idea...call pet stores or neighbours with dogs - even the rescues again, maybe they have dog cages. Put the kittens in a SMALLER cage (not too small) that will fit inside the dog cage.

Then mama cat can see them and smell them. Again, you'll have to be watching.

It would break my heart too, hearing her cry for them...that's why I think letting her see them would get her into a cage.

The net mentioned earlier might work, but would really freak her out.

Poor mama! I hope you can get her soon - work on the dog cage thing...

Maybe, as Freedom said, something with the kittens' scent on it would work just as well.

HUGS!