Birds generally have multiple eyelids therefore they could use one to sleep, and the other to clean the eyes, at most. However, an owl actually has three eyelids. To keep things simple in this instance, I’ll describe these eyelids and their most fundamental task:
Upper Eyelid - Blinking
Lower Eyelid - Sleeping
Inner Eyelid (Nictitating Membrane)
It’s true, Owls Blink, They got three eyelids. If an owl stops blinking, their eyes will dry out and get damaged due to injury because they are in continuous contact with environment and the elements.
Owl Upper Eyelid
The upper eyelid of the owl closes downwards, just like humans . Eyelids of most bird species close by closing the lower lid up , therefore the owl’s eyelid functions in a different way. The eyelid is often called the “true eyelid’. In most species of birds it’s only used to sleep, whereas the owls use it when they blink.
Owl Lower Eyelid
Eyelids on the lower part of your eyes are quite simple It closes after the owl rests, and is for relaxation only. Owls require approximately 12 hours of sleep , similar to birds, pigeons and parrots but , unlike other birds most owls are active in the night but sleep through the daytime. They have extremely sharp eyesight, even though they are very farsighted, which is helpful in spotting their prey from afar atop a high tree.
The eyes of owls aren’t real “eyeballs.” Their tube-shaped eyes are completely inactive and provide binocular vision that completely focuses on their prey and enhances depth perception. Eye tubes of owls, or rod-shaped eyes, cylinders which do not move within their sockets the way eyeballs do. Instead, owls must move their heads or bodies in order to view the surroundings.
Owl Inner Eyelid
The eyelid’s interior often referred to as the nictitating membrane , is an opaque eyelid that is moved horizontally, not vertically (sometimes it’s claimed that it is much more in the diagonal direction). The eyelid originates from the inner corner of an eye of the owl, which extends to the outer corner . This can be used as an effect of a window cleaner to cleanse the eyes.
The eyelid can also be useful when owls hunt during their hunt, and if they’re in the middle of hunting however need to shield the eyes against injury or injuries, they can utilize the eyelid as a shield, but still be able to be able to see their prey since this eyelid is transparent. The eyelid is designed to protect the eyes from the elements like wind, prey dust and sharp carcasses and other extreme weather conditions.
|Nocturnal species||n||Average Range of blink rate||Range of Blink Rate|
|Eastern Screech-Owl (Otus asio)||2||1.5 + 0.7||0-3|
|Great Homed Owl (Bubo virgin&us)||7||3.7 + 2.5||0-7|
|Snowy Owl (Nyctea scandiaca)||3||9.0 + 2.7||6-12|
|Burrowing Owl (Athene cunicularia)||2||2.9 + 1.2||0-5|
|Barred Owl (Strix vuria)||4||5.9 + 3.5||2-11|
|Northern Saw-whet Owl (Aegohus acadicus)||3||4.0 + 1.1||2-5|
Blinking of screech owl Video