A Raven flew directly overhead, only fifty feet above me. It made its “rauukkk” call a few times as it flew. It seemingly pirouetted on one wing and dropped down into the upper branches of a large oak tree. It had noticed a leaf and stick nest, maybe gray squirrel. I watched as the raven quietly studied the nest and then it started meticulously pulling the nest apart. A few sticks and leaves were being removed and they slowly trickled down to the forest floor, one stick and leaf at a time. After less than a minute, another raven, not within sight, called and the marauder responded. Within a few seconds, it abandoned its quarry and flew off to join its mate.
[I read on the Mass Wildlife’s website that gray squirrels can breed twice a year, between Jan and Feb, and then during May through July. So maybe this was an active nest, but maybe the offspring were just too young to make much detected movement or noise, so the Raven gave up quickly.]