About a month ago, Bluesman posted on the Bird watching forum about a type of entrance hole that allows Tree Swallows to enter, but not HOSP. He said - "There is a House Sparrow resistent entrance to keep them out of Tree Swallow houses but unfortunately Bluebirds cannot get in this. It works great for Tree Swallows though. I will see if I can post a picture of it. I first heard of it from a man in Canada named Bernie Nikolai. It is simply a 7\8 of an inch tall slot that is about two inches wide. It is in a thin plate around 1\8 inch thick. The House Sparrow cannot enter this but the Tree Swallows being more streamlined and slender bodied can flatten out and get right in. It works so good." The link below is the whole thread. Here is a link that might be useful: Male Purple Martin Using My Clinger Entrance Video!

It would be awesome to have one of those visiting the feeder. My Baltimore Oriole only shows up very early in morning or when nobody is around

Nina, how wonderful! Do you really think the bird is waking you up? How clever of him! Regarding your raccoon problem, my feeders are pole-mounted and baffled with a stove-pipe style baffle that keeps raccoons, squirrels, chipmunks, etc. off the feeders. You have to get the extra long ones for raccoons and if it's installed properly it works very well. Your jelly would last through the night that way! That is great you have so many Orioles. In Mass where I live, Mass Audubon has started an Oriole project because they've detected local population declines. Last year I had a Baltimore Oriole nest in the Oak tree right above the deck, so I reported it to the Oriole Project.

Well, it's spring, anyway! Many animals, including the great apes, will mount others to show dominance. It looks weird, but it's how they establish their heirarchy. My poor clueless dog Bubbles has taken to riding Max, a foundling Doberman. Bubbles, uh, well, Bubbles gets on his head.