Yesterday, morning, about 10:30 a.m. about 100 crows gathered in Discovery Park's south meadow. Some of them converged on trees. Others ambled about in crowds on the ground, like shoppers taking in a big sale. I could hear three distinct kinds of cries: a rattle, a musical, raven-like "cronk," and, overwhelmingly, a high, harsh "caw, caw, caw" -- the call crows always give when assembling. I couldn't find a reason the crows were crowding together. They weren't diving at anything. I wonder what they were up to?