Six years ago in late August, Rich Levad, Rob Sparks, Jason Beason and Ken Behrens hiked through spruce fir forest to a spot just above timberline where a Black Swift nest clung to a wet, rocky outcrop. The outing was part of Rocky Mountain Bird Observatory’s effort to collect baseline data on this little-known species. When no swifts were seen that evening, the scientists wondered if they had already started migrating – and where did they go?