Owls have large heads primarily to accommodate their enormous eyes. Their eyes take up a significant portion of their skulls and are specially adapted for low-light conditions. The size and structure of their eyes enable owls to gather as much light as possible in the darkness and effectively hunt their nocturnal prey.
Binocular Vision:
The positioning of their eyes on the front of their heads provides them with binocular vision. This means they can use both eyes simultaneously to focus on objects, resulting in a heightened depth perception. Having such precise depth perception is critical for owls as they need to accurately judge distances when hunting and navigating through complex environments.
Eye Tube Structure:
Unlike humans, owls have specialized cylindrical structures surrounding their eyes called eye tubes. These tubes restrict the movement of their eyes, but they do allow for excellent forward vision. This limitation in eye movement is compensated for by the flexibility of their necks, which can rotate almost 270 degrees in either direction, granting owls a wide range of vision without the need to move their heads as much.
Enhanced Vision in Low Light:
Owls have highly sensitive retinas that contain a large number of light-sensitive cells called rods. Rods are particularly adept at detecting movement and work well in low-light conditions. Combined with their large pupils and unique arrangement of eye structures, owls can perceive and capture prey in environments too dark for humans or many other animals.
It's worth noting that while owls do have relatively large heads to house their eyes, the overall size of an owl's head can vary depending on the species. Larger owl species, such as eagle owls and great horned owls, have proportionally larger heads compared to their bodies than smaller owl species, such as screech owls and elf owls.