Has anyone used a sparrow shield? Does it work? It’s basically like the Magic Halo. I found it on the Michigan Bluebird Society website. There’s a picture of it there. Would I just leave it on the nest box all the time? Wouldn’t it deter bluebirds from choosing that box? Scroll down a little bit to see the sparrow shield. https://michiganbluebirds.org/mbs-store#Traps
SparrowShieldThe Sparrow Shield is designed to be a passive deterrent to keep house sparrows from claiming a nest box. The metal ring has 4 lines which hang down around and in front of the entrance hole. The weights are 1/2 ounce ultra steel on the heavy duty twisted lines to help keep them untangled and help prevent birds from getting tangled in them. Bluebirds and Tree Swallows don’t mind flying between the lines, but sparrows dislike it. To be effective, the Shield MUST be installed on the nest box BEFORE sparrows claim the box. This device has proven to be effective most of the time, but occasionally very persistent sparrows will thwart it. The Sparrow Shield comes with a cedar mounting bracket and 2 screws that will fit on almost all Bluebird house designs. It also comes with instructions. (Nest box not included)
Note: The Sparrow Shield is designed and built by MBS member Gene Wasserman and his company WoodCraft Kits. WoodCraft Kits is a not-for profit, hobby business . Each item is made by hand in a home workshop by Mr. Wasserman. He does this as a way of donating to MBS, helping bluebirds, promoting birding and keeping busy now that he has retired.