Do all 3 gibbon islands have 1-2 climbing structures? What did you think of the ape habitats? From photos the islands appear to be very small, but there are 3 of them and the "over-the-heads-of-visitors" gimmick is really cool.
They have about 2-3 fake trees each with a bamboo ledge placed sparingly. One Island has a very sturdy live tree while the other two need some more time growing. The ropes seem to connect everything very well so the gibbons can have any opportunities they want.
I personally think this is the only "Great" exhibit at TEP. The gibbons are always active when you see them. Well, the female really is the star, but hopefully the male will soon join her. If you combine the Islands into one they would have very little floor space but a manageable height. I think the main reason the island works so well, is that the gibbons have so much to look at. They can see all of TEP and then some from one of their islands. It leaves the gibbons very curious since the only barriers are height and water.