From Smithsonian‘s website a story about the most mysterious bird in North America:
Black swifts, Cypseloides niger, are among the most enigmatic birds in North America. Though the species has a huge range, breeding as far south as Honduras and as far north as Alaska, the birds’ preference for nesting on steep, wet, cold rock faces—ideally behind waterfalls—means that students of black swifts need sure feet, steady nerves and an almost obsessive sense of mission.
The birds’ love of forbidding places also means that no one knows if the species is increasing or decreasing, or exactly what the birds need to survive and reproduce. With the help of amateur bird-watchers like Hurtado, biologists in Colorado and elsewhere have begun a multiyear search for black swifts, hoping to solve these mysteries.
As the light starts to fade, Hurtado and his two companions, Rocky Mountain Bird Observatory ornithologist Jason Beason and U.S. Forest Service biologist Ron Torretta, reach a black swift nest site, a shallow cave in a dark rock wall.
Organikos 