Hiking through Shenandoah National Park in late May, I spent a night camped in a small hollow with about a dozen whip-poor-wills. They started singing around 9:00pm, just as it became full dark, and didn't stop until first light. For maybe 15 minutes it was very cool. Wow! Whip-poor-wills! Then I spent the rest of the night wishing for a shotgun. Earplugs didn't help at all. The cry of a whip-poor-will sitting a few feet outside your tent is best described as "piercing."
Nice photo, though.