Osprey are raptors found around nearly every body of water. Some may even migrate great distances in pursuit of ideal habitat. Perched or flying above rivers, ponds, reservoirs, coral reefs and here throughout the lowcountry; our salt marshes. Their simplistic stick nests can be found in dead trees, on man-made osprey platforms and even using channel markers as foundations. The nests are most often positioned in wide open spaces, often right over the water. They are visual hunters who use open perches or flying in their unmistakable M shape to scan the water for fish using their incredible eyesight.
Osprey eyes have four types of color sensors compared to our three, this allows them to perceive ultraviolet light along with the light visible to humans. Along with binocular vision they have an amazing peripheral field as well, giving them a wide range to the sides. Osprey also have dark feathers surrounding their eyes to reflect the sun’s glare bouncing off the water. Even more advanced is their calculation of the refractive index. Determining exactly how deep prey is as water depth changes the angle a fish might appear from above vs under water. Scientists even think they can ‘see’ the earth’s magnetic field which allows precise navigation over long migrations. An osprey’s right eye contains specialized proteins which are thought to perceive the earth’s magnetic fields.
Like most birds of prey, an interesting way to determine the age of an osprey is to look at the color of their eyes. They are born with dark blue or black eyes and after a few days the eyes will change to an amber color. Once the youngsters fledge they typically head on a migration all the way down to South America, amber eyes and all. When they return north after 1.5-3 years, they return with amazing bright yellow eyes, marking them as mature and ready to breed!
Post by Matt Luzon (Captain)