Last night I was sitting at the laptop reading when I started hearing bee-eaters! It was pitch black outside, 23:30 local time, and the sun had set about 3 hours previously. There was no Moon. I grabbed my sound recorder and went outside. I could not see any birds, as it was really dark, although I did see something moving below the street lights, but it was probably bats. It was obvious that there was a flock of many birds moving around.
I have never heard bee-eaters at night previously in the 15 years we have lived in Spain. If you want to hear what they sound like in the silence of night time, listen here.