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What Is The Biggest Owl?

Dear Bird Folks,

As you probably know, owls have become popular in recent years. This led to a family discussion over the holidays. My sister claims the Great Horned Owl is our largest owl, while I think the Snowy Owl is the biggest. Who do you think is right?

– Darlene, Kingston, MA


That’s nice, Darlene,

It’s nice to hear that at least some families are discussing birds when they get together. Birds are a much safer topic than politics right now. And even though your family managed to turn the benign subject of birds into an argument, it’s okay. Half the fun of getting together is doing a little verbal sparring with your siblings. With that in mind, you’ll be pleased to know that your sister was totally wrong. The Great Horned Owl is not our largest owl. But before you call or text her, or brag about it on Facebook, you need to know that your answer wasn’t correct either. Sorry, kid. While Snowy Owls and Great Horned Owls are big birds, North America has an even larger owl…sort of. I’ll explain.

If each of North America’s owl species were arrested and placed in a police lineup (I know it’s a weird concept, but just go with it for a minute), the smallest bird in the lineup would be the Elf Owl. Measuring only 5-3/4” long, the ridiculously small Elf Owl (the world’s smallest owl) is barely the size of a sparrow. At the other end of the line, with a body length of 27” (or five Elf Owls stacked on top of each other) is North America’s largest owl, the Great Gray Owl. By comparison, the Snowy Owl is only 23” long. But here is where it gets tricky. The great gray’s body weight is nearly 40% less than that of the smaller Snowy Owl. How can that be? It turns out great grays are bulked up with a lot of extra feathers. Thus, their true size is a little deceptive. Great grays are like a bag of potato chips. The package is much greater than what is really inside.

Judging from my daily owl discussions at work, I have a feeling many folks aren’t familiar with Great Gray Owls. This is because most of them are found in the wilds of Canada and Alaska, and are rarely seen in New England. My only personal experience with a Great Gray Owl happened in the winter of 1984. One was reported hanging out in a frozen field near the town of Hadley. Excited to see one of these unusual birds, I decided to make the long three-hour drive to Western Mass. At first I had a little trouble finding the exact field, but once I found it I had no problem locating the bird. On one side of the field, sitting on a tree branch, was a sleepy Great Gray Owl. On the opposite side of the field were about two hundred freezing bird watchers, all staring through an assortment of binoculars, scopes and cameras. The owl must of have thought we were all idiots…and it was right. After about five minutes of standing in the snow, I decided that this wasn’t the natural experience I was hoping for. It was a bit sterile. So I got back into my car and did something more gratifying…I drove off to find the nearest source of hot chocolate.

Snowy Owls, on the other hand, are fan favorites and we see them just about every winter. But in spite of their cuddly white appearance, Snowy Owls are ferocious hunters and are not meant to be hugged. The list of the creatures that they will kill and eat includes fish, ducks, puffins, crows, rabbits and geese. Even birds the size of herons are no match for a hungry snowy. Meanwhile, the menu options are not nearly as extensive for the less powerful great grays. Most of what they eat is mice and voles. Finding such tiny prey in the dark isn’t easy, but it’s even harder in the winter when food is hidden below deep snow. This is when the owls switch hunting techniques. Instead of scanning for prey, the birds “look” for food with their ears. Great Gray Owls have the ability to track down mice, even if the mice are concealed by a foot of snow. How is that possible? The birds have asymmetrical ear openings, meaning their ears are on slightly different locations on the sides of their heads. While this might not be a good look for humans, it allows the birds to pinpoint the exact location of any rustling mice. Often, snow will be covered with a layer of icy crust, a crust so thick that even adult humans can walk on top of it. But this tough coating doesn’t deter the owls (or protect the mice). The birds simply clench their feet into a “fist,” dive down and blast through the hard top layer on their way to a warm mouse dinner. (Those poor mice never catch a break.)

Seeing a Great Gray Owl here in Massachusetts is truly a rare occurrence. A far more reliable location to see one is at the famous Sax-Zim Bog, just north of Duluth, MN. The bog is noted for unusual birds, as well as for having wicked cold weather. Each February they hold the “World’s Coldest Birdathon.” Sometimes I think about attending this Brrrrdathon, but since I still haven’t warmed up from my trip to the frozen field in Hadley, I don’t think I’m heading to Duluth anytime soon.

Tell your sister you spoke with me, Darlene, and I said she was wrong about the Great Horned Owl being our largest owl. Whether you tell her that you weren’t right about the Snowy Owl either is up to you. Although that doesn’t mean I won’t mention it to her. After all, there’s no reason for me to keep this a secret. Unless, of course, you were to entice me with a nice mug of hot chocolate, then my lips are sealed…except to drink the hot chocolate.