Eastern imperial eagles (Aquila heliaca) are large birds of prey that breed in southeastern Europe and extensively through West and Central Asia. They are typically the largest eagle species in their range, with the largest extremities (i.e. tarsal, tail and bill length) and most powerful booted eagle species. Adults have a distinctive plumage that is considerably darker than other adult Aquila eagles in central Eurasia, with white spots on the wing mantle and greyish under-tail. Juveniles have a unique tawny-buff plumage covered in brownish streaking, a color combination not seen in other species.
Can Eastern Imperial Eagles See at Night?
No, eastern imperial eagles cannot see as well at night as they can during the day. Like other birds of prey, eastern imperial eagles have excellent daytime vision, but their night vision is not as good.
Birds of prey, including eastern imperial eagles, have a high number of photoreceptor cells in their retinas, which allows them to see a wider range of colors and more detail than humans. They also have a structure called the “fovea” in their retinas, which gives them binocular vision and allows them to focus on their prey with both eyes. This makes them highly skilled hunters during the day.
However, their night vision is not as advanced as their daytime vision. While birds of prey can see better than humans at night, they still have difficulty seeing in low light conditions compared to their daytime hunting abilities.
Hunting Behavior of Eastern Imperial Eagles
Image source: eastern imperial eagle By Koshy Koshy
Eastern imperial eagles have a varied diet, primarily taking their prey on the ground. They are known to hunt in open areas, extending to beyond typical grasslands to wetlands and agricultural areas. In more extensive wooded areas, they require glades or meadows in order to execute hunting.
They are somewhat varied in hunting techniques but almost exclusively take their prey on the ground. This includes small to medium-sized mammals, birds, reptiles, and even carrion. Their powerful talons and sharp beak make them well-equipped to capture and kill their prey.
Adaptations for Daytime Hunting
Eastern imperial eagles have several adaptations that make them highly effective daytime hunters:
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Keen Eyesight: As mentioned earlier, eastern imperial eagles have a high number of photoreceptor cells in their retinas, allowing them to see a wider range of colors and more detail than humans.
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Binocular Vision: The fovea in their retinas gives them binocular vision, enabling them to focus on their prey with both eyes.
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Excellent Depth Perception: Their binocular vision also provides them with excellent depth perception, which is crucial for accurately targeting and capturing their prey.
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Powerful Talons and Beak: Their strong talons and sharp beak are well-suited for grasping and tearing their prey.
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Soaring Ability: Eastern imperial eagles are skilled at soaring, which allows them to scan large areas for potential prey from a high vantage point.
Limitations in Night Vision
While eastern imperial eagles have exceptional daytime vision, their night vision is not as advanced. This is due to the following factors:
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Lower Photoreceptor Density: Compared to their daytime vision, eastern imperial eagles have a lower density of photoreceptor cells in their retinas, which reduces their ability to see in low light conditions.
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Lack of Tapetum Lucidum: Many nocturnal animals, such as cats and owls, have a reflective layer called the tapetum lucidum in their eyes, which helps them see better in the dark. Eastern imperial eagles, like other diurnal birds of prey, do not have this adaptation.
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Smaller Pupil Size: Eastern imperial eagles have smaller pupil sizes compared to nocturnal animals, which limits the amount of light that can enter their eyes at night.
As a result, eastern imperial eagles are primarily active and hunt during the day, relying on their exceptional daytime vision to locate and capture their prey. Their night vision is not as well-developed, making them less effective hunters in low light conditions.
Conclusion
In summary, eastern imperial eagles are highly skilled daytime hunters, with exceptional visual acuity and adaptations that make them well-suited for hunting in bright light conditions. However, their night vision is not as advanced, and they are not as effective at hunting in low light environments. This is a common characteristic among diurnal birds of prey, as their visual systems are primarily adapted for daytime hunting.
References:
– https://www.thainationalparks.com/species/eastern-imperial-eagle
– https://www.oiseaux-birds.com/card-eastern-imperial-eagle.html
– https://wildart.works/behindthelens/eastern-imperial-eagle
– https://en.wikipedia.org/wiki/Eastern_imperial_eagle
– https://www.audubon.org/news/how-birds-see-world-around-them
