Scouting means birds are looking for a place to nest & raise young when the time is right. I didn’t realize your blues were roosting in your box – probably means they will use that box for nesting, also, but other birds do try to take over when the season is here. If you are sure it is blues roosting and now HOSP or something else, that might make a difference on when to remove the nesting material, as they be using it for extra warmth and you could wait until later on to remove it. My blues stay here all winter & eat every day, but they do not roost in their boxes but the HOSP will try to. I usually then trap them. Predators are many, but include coons, snakes, cats (anything that can climb), along with wasps and of course their main predators are the house sparrows (HOSP) and starlings. House wrens will pierce eggs & throw them out on the ground, but are a protected by law species. I’m not sure about how far apart in the woods your boxes would need to be, but normally blues boxes need to be about 300′ apart, as they are very territorial. If you have not tried the sialis.org website, do so – it is like our bible for birding. It is VERY thorough, so it may take you all winter to get through it. Bet Zimmerman Smith is the author of this website, and is on the Board of Directors of the North American Bluebird Society (NABS). Check it out.
