You might have better luck using a large net, if you have one. I owned iguanas for many years, and they will bite HARD if threatened, as well as claw the heck out of you and lashing those tails like a bull whip. They are also very fast, so it would be hard to just go up and catch one. Also, if you have a garage or shed you could lure him/her into with food, and then shut the door, that might be an option. I've never seen one with a split tail like that, it's pretty amazing. Oh, and definitely do not grab the tail only, as they will just drop their tails and run off, and you are left with a (still squirming, ewwww!) tail in your hands.
Please do NOT feed cat food!!!! Yes, they will go after it, but animal protein destroys their kidneys and liver. Ichabod, my first rescue iguana, had been fed animal protein to "bulk him up" by his previous owners. That along with horrific caging conditions left him with barely functioning organs, deformed bones and back legs that were almost useless. Oh, but he was very bulked up, how nice.

He only lived another couple of years after I rescued him before dying of massive organ failure at age 6 despite every effort the vet and I made for him. My next iguanas never ate animal protein in their lives, were still plenty "bulky" (4'6" females) though it actually took PATIENCE and good diet instead of a quick "steroid-fix" with killer animal protein, and both lived to be nearly 18 years old. No matter how much they may love it, it will kill them in the end, so don't do it!!
Most iguanas are pigs for fruit, even though the greens are better for them. If you lure him/her in with a big plate of leafy greens (mustard greens, collard greens) topped with berries, shredded apple, and even some shredded orange squash, you might be able to stage a capture. Also they love dandelions (the leaves and the yellow flowers), if you have access to any that are not sprayed with chemicals or polluted by proximity to a heavily traveled road (car exhaust and spilled oil).
Keep us posted if you decide to give it a try!
