A broad-tailed hummingbird, specifically male, is taken into flight in Colorado for a scientific study on color perception.

In a groundbreaking study, researchers at Princeton University have discovered that broad-tailed hummingbirds can distinguish spectral-colored feeders from feeders in nonspectral colors. This finding offers a significant step forward in our understanding of color vision in animals.

Over three field seasons from 2016 to 2018, the scientists, led by Mary Stoddard, conducted 19 experiments and tallied some 6,000 hummingbird visits near the Rocky Mountain Biological Laboratory in Colorado. The study, published this week in the journal Proceedings of the National Academy of Sciences, involved setting up tube bird feeders outfitted with LED devices near the laboratory. The LED devices were programmed to turn a surface two different colors based on whether the feeder held sugary water or plain water.

The broad-tailed hummingbirds consistently chose the feeder with the sweet taste, regardless of whether it had a nonspectral or spectral hue. This ability likely helps hummingbirds locate a diverse variety of plants and their nectar. According to Stoddard, seeing the hummingbirds discern the colored feeders was "one of the most exciting things" she has ever witnessed.

Hummingbirds, unlike mammals, are tetrachromatic, possessing four types of color-sensitive receptors or cones. This means they can discern colors in the ultraviolet spectrum, which includes UV-green and UV-red. This superior color vision likely evolved to help hummingbirds find food more efficiently in their complex and colourful environments.

Trevor Price, an evolutionary biologist at the University of Chicago, hailed the study as a "big step forward" and offers the most thorough look at how birds distinguish color to date. The results of the study apply to all birds with tetrachromatic vision that are active during the day, as well as several fish, reptiles, and invertebrates.

The study suggests that our understanding of color vision in animals is still in its infancy. While some bird species, such as certain types of parrots, are known to have superior color vision compared to humans, specific recent studies on this topic are not mentioned in the provided search results. Dinosaurs, which are thought to have sported colorful feathers, might have had an extra level of discernment similar to hummingbirds.

The study's findings also highlight the diversity of color in nature and how species differ in their ability to perceive color. As we continue to explore and understand the complexities of animal color vision, we may uncover new insights about the evolution of color perception and its role in the natural world.