With a Hazelnut.
Happening now in the backyard Walnut tree. I expect to find swarming hives in Spring time but not in fall.
First I thought Coyote. But upon further review and a little dissecting it had "felt" and with adding water was extremely pungent.
These were the smallest ants I have ever seen, so tiny. Some have wings.
Our annual Vaux's Swift roost on their way to Central America.