Birds have excellent color vision, relative to humans. Humans have three color cone types in their eyes, sensitive to blue, green and red light, respectively. Birds have these three cones plus a fourth which is sensitive to ultraviolet light. Because of this it has long been unclear how avian color perception works. To answer this question, it is critical to study birds in their natural habitats. This research program will investigate mechanisms of color vision in wild hummingbirds, which rely on color for foraging and courtship. The investigators will perform detailed color-learning experiments in the field, combined with physiological and genomic studies, to understand how hummingbirds use color perception in their daily lives. This will provide new opportunities for testing ecological and evolutionary hypotheses about pollination, mate choice and plumage coloration. Because tetrachromacy (four color cone types) developed in early vertebrates (and exists in birds, many fish and reptiles), uncovering the details of hummingbird color vision will provide a deeper understanding of color vision in many animals. Overall, this work will contribute broadly to the fields of learning and memory, neurobiology, human color vision, colorblindness and vision-related diseases. Hummingbirds are also of great ecological importance as critical pollinators and bioindicators of environmental health, and this research will provide insights into how they perceive the world. The researchers will design in-depth educational programs for middle school students, to be held at the Rocky Mountain Biological Laboratory, in schools and at natural history museums. In addition, the researchers will convene a workshop highlighting recent breakthroughs in hummingbird research and conservation.
This integrative study will improve our understanding of avian color vision. Birds have an ancient and sophisticated color vision system, which they use to find food, identify mates and navigate through complex landscapes. In recent years, detailed psychophysical experiments in laboratories have yielded important insights into the mechanisms of color vision in birds. However, laboratory experiments often lack ecological context and reveal little about how individuals in a population may vary in color perception and cognition. As a result, we have a limited understanding of how birds use and process color information in the natural world. This project investigates mechanisms of color perception/cognition in wild, free-living hummingbirds at the Rocky Mountain Biological Laboratory in Colorado and the surrounding area. This research program has four main aims. First, the investigators will test standard models of avian color vision using field-based behavioral experiments. Second, they will design ecologically relevant experiments that account for colors hummingbirds experience often in the context of foraging and courtship. Third, they will determine the physiological mechanisms responsible for color vision in hummingbirds. Fourth, they will explore the genetic and genomic mechanisms underpinning color vision, particularly with respect to the genes for ultraviolet- and shortwave-sensitivity. Hummingbirds provide a compelling study system because they forage from diverse plant species with colorful floral displays and, consequently, can quickly learn and remember different colors. Using advanced psychophysical tools and RFID technology, combined with physiological and genomic analyses, this project will provide a mechanistic picture of how color perception works in wild hummingbirds.
This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.
