Previous research has shown that people feel better in bird-rich environments, but Christoph Randler, from the University of Tubingen, and colleagues wanted to see if that warm fuzzy feeling translated into measurable physiological changes. They rigged up a park with loudspeakers playing the songs of rare birds and measured the blood pressure, heart rate and cortisol levels (a marker of stress) of volunteers before and after taking a 30-minute walk through the park.
Birds dazzle us with an extraordinary variety of colors and songs, signals that play a major role in how they communicate, attract mates, and evolve. Yet even after decades of research, many mysteries remain. Why do some males adopt drab plumage that makes them look more like females, despite the advantage of brighter colors in courtship? How do songs and plumage patterns influence not only the formation of new species, but also unexpected connections between them?