From New Mexico Wildlife Center
There's a cool secret hidden behind the flat facial disc of a Northern Saw-whet Owl: absolutely enormous ears!
While Northern Saw-whet Owl 24-988 was sedated for a bandage change recently, we parted the feathers at the edge of her facial disc to show one of her ear openings.
This species has asymmetrical ears - one placed higher than the other - which gives them the ability to hear in three dimensions! We humans, with our symmetrical ears, can judge pretty well how near or far a sound is and whether it's coming from our left or our right, but it's difficult for us to tell whether a sound is coming from up high or down on the ground.
That's not a problem at all for a Northern Saw-whet Owl, since they can notice in an instant when a sound coming from down low reaches their lower ear a fraction of a second before it's detected by their higher ear.
Those ear openings are so large that it's possible to see the back of an owl's eye through the ear hole. See that darker, bluish-grey structure in the ear? That's the back of 24-988's right eye!
Owls' eyes are also enormous - each one about as big as their entire brain - which allows them to see very well in the dark, but it also means that when an owl sustains a head injury, there's also a high likelihood of injury to one or both eyes.
When we do an intake exam on an owl, we often look into the ears to check for bruising on the back of the eyes. In 24-988's case, she did have a minor injury to her right eye, which healed quickly with medication.
Her ears and eyes look great, and her fractured femur and scapula are also nearly healed!
I figured the flaps would be to keep dust and things out of their ears, but apparently they can be moved to help focus or filter sound. Source 1 (easier to read). Source 2 (more technical). Ctrl+F "flap" in both articles.
I saw a couple places that said closing the flaps can block out noise while the owls sleep.
It would make sense if you had super hearing that there would be situations where you may want to have a damper for that power. My head hurts too much from not feeling good to read the articles yet, but I did skim them a bit and there's some really good flap pics in there! Thanks for sharing them. You've been bringing a lot of great stuff to me this week and I appreciate it!
I'm pretty sure I have better than average hearing, and it does get a little tiring sometimes. Whether it's high-pitched background noise, or turning on the good equipment and listening to something I like. It's work to process a lot of sound.
I like researching things, seeing the pictures, and reading the stories here. Always a small highlight that brightens my day. Had some headaches too this week, not fun. Hope you feel better soon :)