The good people at Raven Ridge Wildlife Center shared this post and I found it fascinating how and why the eyes change color so many times. What an studying way to determine the bird's age!
We have recently been admitting a large number of Cooper's hawks, and the finders are often surprised by how quickly we can identify them as nestlings or juveniles. One of the first distinguishing features is the color of their eyes. Did you know that many young birds have blue or light-colored eyes due to their limited exposure to light and lower melanin production in early life? As they mature, their eyes usually darken as melanin production increases.
Melanin is the pigment that determines the color of eyes, skin, and feathers. In young birds, melanin production is still developing, leading to lighter eye colors, often blue or gray. Limited exposure to sunlight in the nest contributes to the lighter eye color of baby birds. As hawks grow and are exposed to more sunlight, their melanin production increases, causing their eyes to darken-typically to yellow or orange-as they transition to adulthood.
While many raptors exhibit this change in eye color, the specific colors and timelines can vary between species. For example, the eye color of a Cooper's hawk changes from bluish-gray to yellow and then to red. This information is valuable to our team, especially when we request pictures, which is why we often ask, "What color are the bird's eyes?"
What color is your favorite? I think those light blue ones suit it very nicely!
