Got a call on a bunch of wild felines that the neighbor and home owner have been trying to take care of them selves but after 12 the rest of the ferals caught on so NOW they are asking for my help with the remaining 20 or so. Any tricks with trap wise ferals???

Couldn't keep them away from fox gland lure in my past experience!

Gang set always. Catch them fast before they become wise to them. IMO, behind releasing them from the trap the number one resaon for trap shy is playing with one or two traps when you need a dozen.
Once trap shy good dang luck. I know folks who swear it can be done with conventional cages but I say BULL. The dumb and starving maybe but feral cats as rule once burned will not repeat the mistake. If you must do cages try these tricks Cover the cages and or blend them in with brush to make cubbies, cover the floor with dirt/grass, try double door traps. Kirk DeKalb has one that I want to try that is a short trap that has a huge opening. Look up his videos on utube for the bobcat one.

Maybe one of these would work-
http://www.youtube.com/watch?v=h7tflENb19c

http://www.youtube.com/watch?v=tgsEjqXlRng

I think this one has shot for trap shy ferals due to the large door size and the fact that they don't have to "commit" as far.

I'd say the first thing is to find out who's feeding them and try to put a stop to it. It's easier to catch a hungry cat. 30+ cats is a big colony. They're getting fed somewhere.

Then spend some time observing them if you can. I've found they travel the same routes, at the same time each day. Having the traps hidden along their travel routes helps quite a bit.

I'd also suggest using fresh traps. I've noticed that once I've caught a dominant male the females and young males will give that trap a wide berth from then on. I've used a trap that stunk of tomcat when trapping another dominant male with some luck though.

Keep changing bait if things slow down. Maybe start with cat food. Switch to sardines when the cat food doesn't work. I had good luck recently with salmon oil as a trailing scent with sardines in the cage.

I also like to hang a cd on a string above the trap to attract attention. I've revived played out areas with that trick.

Truism!

If and it is probable...someone is feeding the cats. Find out what food they are feeding. Cover your traps and use that same food.

I have the same thing to set up tomorrow. Some of these have been trapped and spayed or neutered within the past year. Supposed to be about a dozen total. We'll see in a few days.

Yeah, as one who does so-so on wised-up ferals, I'll be waiting for your results.

I bait with a good wet food, hang some feathers from the back and throw some cat nip inside. covering the traps is always a good idea.

left one I think. Will go back and catch him off gaurd in a couple weeks.

yep