This is the biggest collection of flies I've seen at this location so far. They ended up attracting the attention of the yellowjackets, which frequently broke them up. Once the wasps left, the flies would slowly creep back onto the poop.
Flies other than the greenbottles also started joining these feasts. As you can see on the bottom of photo 1 & 2, there were two bluebottles present as well. Sadly, the wasps scared them away before I could take a photo. The bluebottles did not come back.