******* About sticky stuff...I wonder if gum arabic (made from Acacia Senegal and other species) might not do. It is available in a powder form that just needs to be mixed with water. With a large volume of water it remains liquid for a long time; with less water it thickens up rather quickly and is moderately sticky. I believe it is used commercially in the making of ice cream, mucilage, and other things. When we had Galago moholi in the lab, we used to make it up, smear it on sticks and allow the bushbabies to scrape it off at their leisure. The bushbabies loved to eat the stuff. Perhaps you could find the right consistency so that it would fix to the cages and also hold small food items. As I recall, it was not very expensive and came in a large round cardboard container of maybe 20 lbs. {Note: Acacia gum is available at not so cheap prices from BioServ--KE)
******* I have not used this myself, but have read about using a flour paste to paint seeds, etc. onto surfaces. Then just let it dry.
******* regarding mirrors I have some experience from mirror studies (not permanent installations, but left in cages of apes for several days to weeks). We have tried plexiglass-covered glass mirrors, chrome mirrors, and foil mirrors, and the conclusion is that there is nothing that measures up to regular plate glass mirrors. But don't they break? Solution: One simply glues the plate glass mirror with the help of epoxy (two component) glue to a solid plywood backing, at least half an inch thick, and that way you have a solid mirror unit which would need bashing with rocks to break, and even then the pieces would tend to stick to the backing. You should count on quite a number of tubes of epoxy for this, a "flat mount" like that consumes more glue than one generally imagines. And mix the epoxy on the flat plywood itself, and not in a container, to keep it from going into run-away curing by volume heat retention.
