Wild hummingbirds see colours that humans can only imagine: Study

Field experiments led by Princeton University researchers found that hummingbirds can see colours that humans "can only imagine". While human eyes typically have 3 types of colour cones attuned to red, green and blue light, birds have a fourth type, sensitive to ultraviolet light. The hummingbirds were able to discern a variety of "nonspectral-coloured" feeders from feeders in spectral colours.