Just about everyone notices chickadees. Black-capped Chickadees are popular research subjects, too—easy to band and keep track of, readily nesting in artificial nest tubes, and distributed over a wide range in North America. Their vocalizations, interactions with other species, social hierarchies, food caching, winter survival, and brain-neuron regeneration make them fascinating research subjects.
In many species that mate for life and share nesting duties, male and female plumages look identical to our eyes. Chickadees see ultraviolet wavelengths, apparently detecting differences between males and females. To them, males have significantly brighter white and gray areas, larger bibs, and a stronger contrast between white and black areas than do females. Daniel Mennill of the University of Windsor and his colleagues detect and measure these differences using a spectrometer. Dan says, “After a decade of working with these birds, I still can’t distinguish a male from a female, or a high-ranking from a low-ranking male, even if I’m holding them in my hand. However, the spectrometer uncovers things that are hidden to our eyes. Birds’ eyes are so superior to ours that we expect that they pick up on these differences readily.”
These findings provide scientific confirmation that there is more to chickadees than meets the eye.