For years, biologists described the dusk-dwelling oilbird as a rare case of a bird that navigates in total darkness by making audible clicks and listening for echoes. The closely related potoo, however, was assumed to rely only on its large eyes when flying at night. After placing microphones and cameras along a forest trail, researcher Lina Chen and her team argue that potoos also use their own clicks to help avoid obstacles in low light.
Which finding, if true, would most directly support Chen and her team’s argument?