The first time I heard a whip-poor-will was while thru-hiking the Appalachian Trail. Rich and I and about 6 other hikers were sound asleep in a shelter (I think in New York State) when a Whip-poor-will landed on the picnic table in front of the shelter and gave his call loud and clear. We all sat bolt upright. As I mentioned, I had never heard one of these birds before, but by it’s call, I knew its identity immediately. Someone threw a boot from the shelter toward the bird and we all settled back to sleep.
I had spent my whole life in the Rochester area and had never heard a whip-poor-will previously. Of course I predate the 1980-1985 survery shown on the breeding bird atlas by a few years (just a few!), but still looking at the comparison of then vs now you can see how dramatically their rance has declines. Take a look here: NYS Breeding Bird Atlas: Whip-Poor-Will



I’ve been fortunate to hear the call of the Whip-poor-will a couple of times. Never got to see’em though. Very hard to spot in the woods with their plummage.
Sadly, they need old growth forests in both their breeding areas in northern US & eastern Canada and the Southeastern US where they migrate. These forests are slowly being eroded away by development and the changing climate.
It will be tragic if the day comes when one can not hear a Whip-poor-will in the forest.