I have never had this before, I was less than 2 feet from hitting them while mowing today, I called a local bee keeper and he was glad to get them, he came right over and brought a box and a bucket to put them in and take them to his home, he guessed 3-4 thousand. I googled bee swarms and learned a lot. He said they "probably" would not sting me as we were getting ready to cut the limb they were on, I noticed he was in full bee keeper garb with the netted hat and I was in shorts and sleeveless shirt!