A Wasp Nest...I was cleaning up around the back yard when I saw a wasp fly over the fence, and fly back and forth along the fence and finally settle in where she was building a small nest under the top railing. She tended her nest for a couple of minutes and then backed out and looked around and flew away. I checked the nest and she did have some eggs in it. She did this a few times while I was very close. It didn't seem to bother her at all that I was only maybe 3 feet away. If you are aware, bees find their nest by following landmarks, just as we do. You probably know the names of the streets in your area but few actually drive that way. "Go down the main road till you see the Ford dealership and take a right, then go 3 stop signs and take a left and when you get to the 7-11 take another left and it's the 4th house on the right." Bees are the same. When they leave their nest or hive they fly backwards, and they can also fly sideways, like hummingbirds, and they are checking the landmarks so they can get home, and they do that throughout their flight.
I watched her for a number of flights and then after she left once I reached in and took the nest down. When she returned the confusion was obvious. She flew back and forth and up and down and then went back over the fence and quickly came right back. The nest wasn't there and she was thrown. She did that repeatedly and it got sad. I could picture her confusion and sense of loss. So I killed her.