The interesting thing to me is why? What would cause this evolution? Most swifts fly all day and can barely perch, but they do perch for the night since they re

The interesting thing to me is why? What would cause this evolution? Most swifts fly all day and can barely perch, but they do perch for the night since they require sight to locate aerial insects and the effort of flying all night is a big energy drain on a small bird. I can think of only two possibilities: First possibility is that insects are dense enough that they are feeding themselves at night. Second is that the safety of being off the ground plus abundant daytime food makes this a better survival strategy. Can't wait to see what the ornithologists come up with to explain this.