Experiment on color vision underway in Colorado, involving a male broad-tailed hummingbird.

In a groundbreaking study published in the journal Proceedings of National Academy of Sciences, scientists have discovered that hummingbirds can perceive a wide range of colours that are invisible to the human eye. This exciting research, conducted over three field seasons from 2016 to 2018, offers a "big step forward" in understanding how birds distinguish colours.

The study, led by Mary Stoddard, an evolutionary biologist at Princeton University, and her team, involved a total of 19 experiments and around 6,000 hummingbird visits. The team used tube bird feeders outfitted with LED devices near the Rocky Mountain Biological Laboratory in Colorado. The LED devices were programmed to turn a surface two different colours, depending upon whether the feeder held either a small amount of sugary water or plain water.

The hummingbirds' ability to discern colours extends beyond the visible spectrum for humans. They can see a difference between colours that appear the same to us, such as UV-green and simple green. Moreover, they can discern colours in the ultraviolet spectrum, which includes colours like UV-green and UV-red. This ability likely helps hummingbirds locate a diverse variety of plants and their nectar.

Bees, too, can see ultraviolet bull's-eye patterns in yellow flowers that direct them to the nectar. This suggests that the results of the study may apply to various other species with tetrachromatic vision, such as several fish, reptiles, and invertebrates.

Trevor Price, an evolutionary biologist at the University of Chicago, describes the study as offering the most thorough look at how birds distinguish colour to date. He praises the study's experimental approach as "amazingly bold." Karen Carleton, an evolutionary biologist at the University of Maryland, College Park, echoes this sentiment, calling the study an "amazingly bold" experimental approach.

The findings of the study challenge our understanding of colour vision in animals. It suggests that our current knowledge is still limited, and there is much more to discover about the colourful world that surrounds us, a world that hummingbirds and other tetrachromatic creatures can perceive in a way that we can only imagine.

This research also raises intriguing questions about the colour of dinosaur feathers. If broad-tailed hummingbirds, with their extra level of discernment, might have been a trait of dinosaurs, then it is possible that dinosaurs were far more colourful than previously thought.

In conclusion, the study on hummingbirds' colour vision provides valuable insights into the complex and fascinating world of animal colour perception. It serves as a reminder of the wonders that still await us in the natural world, and the importance of continued research and exploration.