Over the years we've had crows who have held what I call conventions or board meetings in our tree out front. Generally, it has been at the most 20 crows cawing. No big deal. We've even had some build nests and raise their young in our tree.
Mid morning I heard such a clatter, that I had to look outside. The noise was deafening.
Between our tree in the front and the trees in the yards of my neighbors on either side of me, we had to have well over 100 crows.