Hummingbirds, not insects, pollinate sub-alpine Castilleja Robert Colwell, University of Connecticut 23 April 2013 We offer a small correction, regarding Benjamin Blonder's photo of summer wildflowers in an subalpine meadow in Colorado. You write: "To whom are these flowers advertising, and what does this scene look like through their eyes? Like the winning image, the ecological emphasis of this photograph is on vision. But there the similarity ends. The similarity between the visual systems of humans and birds does not obviously extend to insects, the intended receivers of these plants' signals. We should perhaps be thankful that as unintended recipients, we can see beauty in this picture." Whereas you are right about some of the flowers in the photo, the one that, to the human eye, is most vivid is the scarlet red Indian Paintbrush (Castilleja miniata, formerly Scrophulariaceae, recently subsumed into Orobanchaceae). This species (like several hundred other species in the genus) is obligately pollinated by hummingbirds, in this case Broad-tailed (Selasphorus platycercus) or Rufous Hummingbirds (S. rufus), who, like us, see red as a vivid contrast to green [1-2]. Robert K. Colwell, University of Connecticut Benjamin Blonder, University of Arizona 1. Raven PH: Why are bird-visited flowers predominantly red. Evolution 1972, 26(4):674. 2. Rodriguez-Girones MA, Santamaria L: Why are so many bird flowers red? PLoS Biol 2004, 2(10):e350. Competing interests None.