@bud_t Thanks! It was incredible. We almost did not get permission to descend that day, as it was rainy and overcast. They will not allow anyone to enter if the swallows have not left (for conservation reasons, which is good!) and they often don't leave on rainy days. But the rain lifted and they started flying out so we got permission to rig and descend. About 2 hours later the rain started back up and we were told we had to get out! I was one the later folk to climb, and while one rope they started to return a bit more en mass. Nothing like hanging on a 11mm rope in free space, over 200 feet from the nearest wall, and having swallows flying around you, spiraling back inside. The sound of them swirling (not chirping, just flapping and air movement) was simultaneously cool and disconcerting!