Some friends tell me birds will eat eastern tent caterpillars if the web has an opening. Although I have a very active bird population in my midwest wildlife garden, I have yet to see any birds eat tent caterpillars. As soon as I spot the tents, I manually remove the tents with a stick. After making a hole in the middle of the web, I scrape the web off the tree, then check it again over the next few days. If I can keep the caterpillars from rebuilding the tents, they usually disappear. I still find the caterpillars in the garden, and sometimes on my roses; I just prefer not to "decorate" my yard for Halloween in spring!