I, too, was wondering if these grackles (large blackbird-type birds) have actually harmed any baby blues. Like Gin says, they would not be able to get to them prior to fledging if the entrance hole is 1 1/2″in diameter and the bottom of the box is proper depth from hole, which I believe is at 5-6 inches. If the nest gets too close to entrance hole, predators can reach inside to grab babies. Also NO PERCH on the box. I have lots of grackles but have never noticed them harassing the blues, but then again, we don’t always see what is happening. Be sure to check out the Sialis.org website for great info. Good luck, and WELCOME to this forum!
