1.  I have a family of crows that I have watched in my yard that appear to be teaching the younger generations to forage during the summer.  I have seen a flock foraging in corn fields once the crop has been cut in the fall. 2. Last fall while looking for snow geese during their migration and stop over in the Lake Champlain Valley, I witnessed a huge flock of red-winged blackbirds.  They literally blackened the sky where they flew.  They landed in several large trees that had shed there leaves and filled them. When they were in flight they flew in such tight formation they appeared to be an art form. I  also regularly see flocks of Canada geese, cedar waxwings, blue jays, and turkeys, but no where near the size of the crows, snow geese, or red-winged blackbirds.

I have noticed foraging flocks in farm fields in the fall. The most common flocks I see are of Canada geese: in school athletic fields, on golf courses, or by the river.

I have seen large groups but I don't know that they were foraging as they were not on the ground. It was more like a "meeting" in the sycamore behind my yard. I believe it was fall or early winter because the tree was bare of leaves. The other flocks that I have seen in my yard were wild parrots and Cedar wax wings. I have also seen groups of pigeons and black birds "brewers?" or "red wing?" on the now weed covered ex dump that is out by the San Francisco bay.