National Park Scouts

The Great Gray Owl: The Bird That Hunts What It Cannot See

Host: Jenni · Topic: Great Gray Owl, animal hearing, hunting adaptations, Yosemite wildlife

Intro

Scouts, don't move. Don't even breathe too loud. It's almost dark out here. We're crouched at the edge of a meadow, and something is coming. There it is. It just flew over. But it was totally silent. Something just landed on a branch two trees over from us. It was almost as tall as your kitchen counter, with wings wider than you are tall. And it made zero sound while it was flying. Zero. Two huge yellow eyes; they just opened in the dark, staring straight ahead like someone flipped on a lantern.

Scouts, that is the largest owl in all of North America. It's so quiet that you can't even hear it flying. Today, we're meeting an animal that might be living in this park and almost nowhere else on planet Earth. Let's go.

One last time to wrap up this series, and it feels right to end it with a mystery. In our first stop here, we chased down one of Yosemite's famous waterfalls. Then we looked straight up at the sheer granite face of El Capitan and met the climbers who take it on. Last time, we stood on top of Half Dome and figured out exactly how solid granite got its dome shape.

Today we're leaving the granite and the waterfalls behind and heading into the meadows at dusk to meet the park's rarest, quietest resident; an animal so well hidden that plenty of people who have visited this park their whole lives have never seen one.

Meet the Great Gray Owl

So let's talk about the animal we just met in the dark, because it has a fun secret. It's called the Great Gray Owl, and it is officially the tallest owl in all of North America. Stand one up next to a yardstick, and it can measure close to two feet, head to tail. Stretch its wings out, and they can reach almost five feet across.

So this must be the biggest, heaviest, and most powerful owl out there, right? Uh, nope. Definitely not.

Here's a question for you: how do you think a bird that's two feet tall could weigh less than a bag of sugar? The answer is fluff; an enormous, ridiculous amount of fluff. A great gray owl usually weighs somewhere around two and a half pounds. That's it. Smaller-looking owls like the great horned owl, which is actually shorter than this guy, weigh more. The great gray owl only looks bigger because it's wearing what is basically a giant poofy winter coat, all day, every day. Picture the fluffiest coat you own. Now imagine wearing five of them, and everyone around you assumes you're twice your actual size. That is the great gray owl's entire personality.

But its face is the real giveaway that something clever is going on underneath. Look closely and you'll see two big round patches of feathers circling each eye, like a target, or a pair of feathery headphones. Scientists call that the facial disc. That disc of feathers works kind of like a satellite dish; except instead of catching a TV signal, it catches sound and funnels it straight into the owl's ears.

And here's a fun, silly fact: one of its ears actually sits slightly higher on its head than the other one. Why on earth would an owl want lopsided ears? Well, it's because it lets its brain compare the exact tiny moment a sound reaches each ear, and uses that difference to figure out exactly where a sound is coming from; not just left or right, but up, down, near, or far.

So here's what we've got: an owl that looks massive but is basically wearing a costume, a face built like a satellite dish, and ears at two different heights on purpose. All fluff on the outside, and on the inside, one of the best built-in hearing systems on the entire planet.

An Owl Named After This Park

And that hearing system is about to become very important, because this particular owl does not live just anywhere. Canada, Alaska, even all the way across Europe and Asia; so you'd think the ones here in California would be pretty much the same as all the others. Scientists weren't so sure.

Back in 2010, researchers tested the DNA of the great gray owls living right here in the Sierra Nevada and compared it to great gray owls everywhere else in North America. And they found something nobody expected: Yosemite's great gray owls turned out to be their own separate group, found basically nowhere else on the planet. Scientists even gave them their own scientific name, Strix nebulosa yosemitensis. It literally means "of Yosemite."

Think about that for a second. This owl has the word Yosemite built right into its actual scientific name. And there aren't very many of them anywhere. Scientists estimate that there are only around 200 to 300 great gray owls left in the entire state of California, and most of those owls live right here inside this one park.

That means Yosemite isn't just a good place to spot one; for most of these owls, it's basically the last place. And that's part of why protecting parks like this one matters so much. When an animal has only one real home left on the map, protecting that home is what keeps the whole species going.

So where exactly in this park is this rare, secretive owl hiding? Some place very specific, right where two totally different worlds bump into each other.

Guess the Park Sound

Okay, scouts, it's time for Guess the Park Sound. I'll play you a sound, and you take a guess at what it is. Are you ready?

What do you think made that sound?

We'll come back to it right after this.

Hunting by Ear

I bet it's not what you were picturing. No screech, no cartoon "hoo-hoo." Just this low, slow call that can roll across a quiet meadow for a surprisingly long way. And here's the thing: almost nobody listening to this podcast right now will ever hear that sound in person. This owl is quiet, it's rare, and it's extremely good at not being found.

So how does an owl that's basically invisible during the day turn into one of the best hunters in this whole park once the sun goes down? Let's find out.

Thank you to the Institute for Bird Populations for supplying us with our park sound today. The IBP researches and advises on conservation efforts for the Great Gray Owl.

Picture a Yosemite meadow, right where the tall trees stop and the open grass begins. That edge right there is exactly where the Great Gray Owl loves to hunt. It perches still on a low branch, watching, waiting. And here's the crazy part: this owl can hunt during the day, at dawn, at dusk, or in total darkness. It really doesn't care.

But winter hunting is where things get almost unbelievable. Picture a little mouse-like critter called a vole, tunneling through snow completely out of sight, more than a football field away. This owl can hear it. Researchers have found that a great gray owl can detect a small animal moving under nearly a foot and a half of snow from up to a hundred meters away; that's the length of an entire football field.

This sounds complicated, but here's the simple version: once an owl locks onto that sound, it doesn't even need to see its prey at all. It just uses its ears. It lifts off its perch, glides low and silent over the snow, and then, feet first, it dives straight down, punching clean through the snow like it isn't even there.

And remember, this is a bird that weighs about two and a half pounds. Scientists have recorded great gray owls smashing through snow packed hard enough to hold up a big adult standing on top. A bird lighter than a bag of flour, breaking through snow that could hold you. It comes back up a second later with dinner, and it never once needed to see what it was catching.

That's not luck, scouts. That's an animal built from the ears out to hunt something it cannot see at all. And it turns out this owl is not the only hunter in Yosemite with tricks like that.

Game: Guess Who's Hunting

Today, we're playing Guess Who's Hunting. I'm going to describe a hunting move, one clue at a time, and you try to guess the animal before I tell you. All three of these hunters live right here in Yosemite.

Round one. This hunter can't see its prey at all; it's buried under grass or snow. So it stands completely still, tilts its head side to side to pinpoint the exact sound, then leaps high into the air and slams down with its front paws to pin its prey. Meadows are its favorite hunting ground. Any guesses?

That's the coyote. This pounce is actually called mousing, and coyotes do it in the very same meadows where our owl hunts.

Round two. This hunter doesn't hunt on land at all. It walks straight into fast, freezing mountain streams and actually walks along the bottom, using its wings to hold itself down against the current, hunting for insects hiding under rocks. It even has a see-through eyelid, so it can keep its eyes open the whole time it's underwater.

That's the American Dipper, the only songbird in North America that hunts underwater. Yosemite's rivers are full of them.

Round three. This hunter doesn't need to see its prey either, just like our first one. But this one hunts at night, drops straight down through solid snow, and grabs something it never laid its eyes on, using nothing but its hearing.

That's our great gray owl. Three totally different hunters, three totally different tricks.

Thanks for playing our game with me.

Scout Question of the Day

Next up is the scout question. And I want you to think about this: have you ever heard an owl hoot outside at night? And what do you think it would feel like to hear so well that you could hunt in total darkness without needing your eyes?

Eli, age 5

"Hi, my name is Eli, and I'm five years old. I have heard an owl hoot. And I go directly... I think it would be incredible to feel like an owl in the dark."

Visit NationalParkScouts.com/contact; let's get you on our next podcast adventure.

The Big Idea

What did you learn today that most adults don't know? I learned that Yosemite is basically the last real home in the world for one of the rarest, quietest owls on the planet; an owl so tied to this one park that its own scientific name literally means "of Yosemite."

Scout Mission

Your Mission

At home, tonight around dusk, go outside and just stand still and listen for two whole minutes; no talking. What do you hear that you'd normally miss completely?

If you're visiting Yosemite, head to a meadow near dusk. Crane Flat is a great one, or any of the smaller meadows. Stand quietly right where the trees meet the open grass; that is exactly the kind of spot a great gray owl hunts. You probably won't see one, almost nobody does. But stand there and imagine one perched silently, just a few trees back, watching the whole time.

Outro

But there is so much more of this park left to explore. Waterfalls we haven't chased, meadows we haven't wandered, stories we haven't told yet. We'll be back in Yosemite again down the road. But until then, scouts, your next adventure is waiting.