Thursday, April 23, 2020

Attract Great Horned Owls to your yard with nest box

This owl, the Great Horned Owl, is probably the most familiar of owls in North America. The deep resonant hooting on cold calm winter nights is familiar to many.

Great Horned Owls are widely distributed throughout North and South America. They are absent only from the Arctic tundra, parts of the Amazon Basin, and the pampas grasslands.

Nearly wherever you live in mainland United States you have Great Horned Owls near you.

Would you like to attract them to your yard more frequently? Read on!



Photo of a young Great Horned Owl on a branch
Fledgling Great Horned Owl
Photo by Greg Gillson

What makes your yard attractive to Great Horned Owls?


These large predators hunt by perching and waiting for prey to scurry by. Then they swoop in silently to attack. They thus need trees or poles for perching. They need some open rough grass or other open areas. They may be more common in second growth forests with edges and openings. But they are common from forests to farmlands to cities.

To attract Great Horned Owls to your yard requires that your property is large and has big trees and open space. It should also abut similar properties or undeveloped areas, woods, farmlands, or grasslands.

There may be good reasons not to attract Great Horned Owls into your yard, though. They are fierce predators. They will hunt small prey such as squirrels and mice. They will hunt larger prey such as rabbits, grouse, and skunks. They hunt and eat all other owls! They will hunt housecats and even small dogs, up to about 15 pounds. So make sure that this large owl will be welcome on your property before enticing them into becoming full time residents.

You can provide nest boxes and platforms to attract Great Horned Owls. I'll discuss that after discussing natural nests.


Peek-a-boo. Great Horned Owl in an old crow nest
Photo by Greg Gillson

Great Horned Owl nests in nature


Great Horned Owls use old hawk, magpie, and crow nests for their nests. They also nest in cliff crevices and derelict buildings and barns. Red-tailed Hawks, American Crows, and Common Ravens probably provide the most nests for Great Horned Owls. These widespread birds help the owl become equally widespread.

These owls may use an old nest as is, without adding anything. Or they may add bark, leaves, or down feathers. They may crush their own owl pellets to add material to the nest.

Courtship begins in winter. Pairs are often heard hooting in the night before the eggs are laid. Great Horned Owls nest from February to April in most places, to June in some locations.

The female lays 1-4 eggs. They take 30-37 days to incubate until they hatch. The young remain in the nest for another 42 days before they are ready to fledge, leaving the nest.

Old hawk and crow nests are rarely reused the next season. Raising young owls often damages the nest making it unusable the next season.

How do you find Great Horned Owl nests? In spring, before the leaves come out, check large trees along fence lines between agricultural fields. Check trees along creeks and rivers. Check trees at the edge of the woods. What do you look for? Old hawk and crow nests. Look for horns sticking up above old hawk nests, as in the photo above!



Here is a very interesting video on the hearing and eyesight of the Great Horned Owl. It explains why this bird is such an amazing hunter.


The Great Horned Owl nest box


You can create a nest for Great Horned Owls by building a wire cone lined with sticks to mimic the nest of a hawk. Here are the pdf nest plans from Nestwatch and the Cornell Lab.

You can also build a nest tray to attach to a tree trunk. Again, weave sticks together to imitate a crow or hawk nest. (Look at how the nest platform is made in the video below.) Add smaller twigs or straw and pack it down to make it firmer for the eggs.

I've even seen a Great Horned Owl using a large metal washtub in a tree as a nest!

These owls may nest in a very large box as long as the entrance "hole" is at least 12 inches high.


Great Horned Owl nest box dimensions


These owls usually use a nest with an open top. They may also nest in large boxes with one open side.

Great Horned Owl nest platform dimensions overview

  • Floor 22x22 inches
  • Side height 8 inches
  • No roof
  • 15-45 feet above the ground

Weave sticks and smaller twigs together to create a nest. You must fill in any larger holes or gaps between sticks. You don't want the eggs to fall down too far. The mother owl must turn the eggs over while incubating.


Great Horned Owl nest box placement


These owls like to have nest platforms in live trees from 15 to 45 feet above the ground. Place in hardwoods (not conifers) that are at least 12 inches in diameter.

You may also place nests in open-sided barns or under cover in similar buildings that aren't used much in the spring. But such buildings are better for Barn Owls. [Great Horned Owls will prey upon Barn Owls (and all other owls), so don't place nest boxes of Great Horned Owls together with any other owl houses.]

Great Horned Owls are used to nesting out in the open in late winter and early spring. Yes, even with snow on the nest! This means you don't have to worry about which direction the nest faces, as with other owl nest boxes.


Here is a video showing a nest platform attached to a tree with sticks woven into it to mimic a hawk or owl nest. The adult owl returns to the nest at time stamp 1:31. (Do I hear Steller's Jay, Hairy Woodpecker drumming, Townsend's Solitaire, and Mountain Chickadees?)



Nest box competitors and maintenance


Really, there aren't many nest competitors for nest sites. Great Horned Owls are likely to be able to drive off any intruder to the nest.

The only animal that is likely to attack a Great Horned Owl is another Great Horned Owl! If they eggs are left unattended a Common Raven might eat them. Fledglings leave the nest before they can fly well. These may be preyed upon by foxes, coyotes, or bobcat.

Young owls are most likely to die from starvation if there isn't enough food. Parents feed the largest and strongest baby first. Only if there is sufficient food and the parents are better hunters do all the young get fed and survive.

You may need to repair and weave the sticks of the nest every year. Or perhaps just add a few new sticks. Do this in early fall when the nest is not in use. As you can see from the above video, it's no work of art! A layer of wood chips underneath may provide some insulation from the cold that may penetrate up through the floor.




You may like: 5 common backyard owls



27 comments:

  1. Thank you so much for this information! I've spotted a great horned owl and an owlet in my backyard this spring I love it when I catch glimpses of them. You're welcome video melted my heart! I'm going to build one of these owl boxes in hopes that they use it for next year. I was wondering... The tree that they reside in now has a lot of horizontal branches, but isn't in my yard. The tree that I'd like to use for the box is in my yard but it's much more vertical. It's a very large, sturdy cottonwood. Should I build anything below the nest box so that the outlets would have a branch/buffer below them in case they fall out while still very young? Or do I not need to worry about that?

    ReplyDelete
    Replies
    1. Some kind of horizontal branch or even a wide shelf around the front of the nest box might be appreciated. But I'm not sure it is absolutely necessary. Build the box. See if they use it. If they mother chooses the box then it is probably good as is.

      Delete
  2. That information is very helpful! However, my neighborhood doesn’t have any open grassy areas, but lots of tall trees. My friend who lives two blocks away from me said that he saw an owl flying over the summer. He also said that sometimes he hears them at about one in the morning. He thinks this is because the owls aren’t as active here because my neighborhood doesn’t have any open grassy areas but lots of tall trees. Is my friend right? Also, I have only heard an owl in my neighborhood once. Is it possible the owls in my neighborhood left or died because of my neighborhood’s lack of undeveloped land? Also, don’t great horned owls attack people that get too close to the tree they are nesting in during nesting season? Also, if I put a really tall pole on my roof, and at the top is a nesting platform, might a raptor or owl use it as a nest? Especially a peregrine falcon? Also, can you make one of these nesting platform advice articles, but for peregrine falcons? Thanks!

    ReplyDelete
    Replies
    1. JBird, thanks for your note.

      From what you describe it sounds like the habitat is a bit to wooded for Great Horned Owl. They do roam over a large area. Perhaps there are more open areas nearby?

      Peregrine Falcons nest primarily on ledges on cliffs well away from people. They need a good supply of ducks or flocking shorebirds to feed upon. Again, their food source requires extensively open lands (tundra, beaches, prairies, or marshes).

      Some do, however, nest on bridges and skyscrapers where they have plenty of pigeons for food, and no direct human disturbance.

      I don't think there are any man-made nesting platforms devised for them.

      Delete
    2. But your land may be right for Barred Owls if you live anywhere but the Great Basin, California, or the SW.

      Delete
    3. thank you! And to clear some stuff up, and some follow up questions. First, I live in LA. Also, there are LOTS of squirrels, crows, and songbirds. Also, the tall trees in my neighborhood are spread apart. Also, can great horned owls snatch sleeping animals from branches like a harpy eagle? Also, I live right by the LA River, where Peregrines are spotted. I also live close to Griffith Park, which is pretty big, and as I think I said previously, I also live close to a park where I’ve seen an owl. What other owls do you think could live in my neighborhood? Thanks!

      Delete
    4. JBird, that helps!

      So the tall trees are likely to be eucalyptus, and not a conifer forest. So there will be Great Horned Owls and Barn Owls. If there is a creek with oaks nearby you should expect Western Screech-Owls.

      The owls are likely to eat mostly rabbits, rats and mice, and squirrels in your area.

      Delete
    5. Thank you! And I DO have a lot of eucalyptus in my neighborhood! But I have never heard a barn owl in my neighborhood and have only heard a great horned owl once in my neighborhood. And about that creak thing, I live VERY close to the LA river. There are also other tall trees in my neighborhood. And I am a little worried about the owls in my neighborhood. If they are still alive. But due to the lack of evidence of an owl in my neighborhood, there might just be one. I am worried because in order to have a substantial food supply, it would need to be active during the day. Is it possible that a great horned owl can pluck sleeping animals from branches like a harpy eagle? Also? I read the barn owl nest box article, and it said that barn owls can’t live near a freeway. I live VERY close to a freeway. I’ve also never heard female great horned owl calls. Could it be possible I have saw whet owls in my neighborhood? Thanks! And sorry for all the questions.

      Delete
    6. Your questions are great, JBird!

      Owls use keen hearing to find prey rustling as they run through the grass or leaf litter. There is no shortage of nighttime mice, rats and other creatures. They may stay up hunting until it dawn, to hunt rabbits and ground squirrels.

      But they won't normally hunt after sunrise. They get mobbed by crows--which may be the best way for you to know an owl is about. A hundred screaming crows dive-bombing a tree is a pretty good sign, though they sometimes get upset by hawks, too.

      The biggest problem is probably the freeway noise at night.

      Still, this is the time of year to listen after midnight and hear Great Horned Owl calling, It is the courtship season for them. I often hear them when my window was cracked open a bit. The owl hooting wakes me, but I am more attuned to bird noises than most--especially in my sleep!

      Barn Owls fly down the street clicking their bills. I think it is almost an echo-location thing. Very rarely will you hear a raspy barking call as they fly past. No courtship "song" as other owls.

      Saw-whet Owls are birds of northern and mountain boreal forests. They probably nest above 5000 feet in southern California mountains. You need to get up to the incense cedar and Coulter pines. Places like Big Bear or other snow play areas.

      Delete
    7. Thank you so much! But I have never heard a great horned owl calls recently, and I stay up after midnight. Is it possible that the owls in my neighborhood stay in the park by my house, and periodically stray into my neighborhood? I also don’t have rabbits in my neighborhood. And the crow in my neighborhood only mob the hawk. Also, if there is no nesting platforms or pre built bird of prey nests, will the great horned owls just not nest? Also, is it possible that I have long rated owls in my neighborhood? I may have heard them before, but I have a lot of dogs in my neighborhood that sound exactly like that long eared owl’s dog like sounds so I really don’t know. Also, could a great horned owl attack me if I make their sounds? Also, in Arizona, at like 5:00 PM, I heard a great horned owl, I found it in a tree and stood under it and kept hooting at it. Even though it knew I was a human it still was hooting, though not at me. It would also look down at me and hoot every now and again. Eventually, there were like five people staring at it from right next to the trunk. Was this owl getting overwhelmed? Also, right next to a busy street in my neighborhood on the side walk, there was a squirrel without a face and crows were surrounding it. The squirrel didn’t look like it was hit by a car, and other that having no face, it showed no signs of injury. Could an owl have done that? Or a hawk?

      Delete
    8. Just wanted to say that in advance

      Delete
  3. greg, thanks for your informative notes.

    I, too, live in an urban area - the southside of Chicago. It 's an old neighborhood, with homes having large yards, and one that is amply supplied with 100 + years-old oaks trees ( many varieties.)

    And, I too have heard owls calling to each other, though not every year. After listening to internet "recordings", think they are / have been Great Horned Owls.

    My question: Does the mere act I periodically hear these wonderful creatures mean that I have a reasonable expectation of successfully inducing one to call my backyard home?

    In advance, thank you.

    Michael

    ReplyDelete
    Replies
    1. Interesting question, Michael.

      Certainly, since you hear owls hooting, they are nesting somewhere nearby. They have a very large territory. But, yes, you may be able to entice owls to nest, if you have some habitat (large trees and open spaces).

      Delete
    2. That sounds more like a suburban area. I live in the suburbs, and from how you described where you live, it sounds much more rural than an urban area let alone a lot of suburbs. It sounds like you live in a place WAY better than mine for owls. Sorry for being knit picky. Have a nice day!

      Delete
  4. I’m guessing I shouldn’t have done that. Sorry

    ReplyDelete
  5. I know I already posted this, but ignore that one I meant to have it posted down here. Thank you so much! But I have never heard a great horned owl calls recently, and I stay up after midnight. Is it possible that the owls in my neighborhood stay in the park by my house, and periodically stray into my neighborhood? I also don’t have rabbits in my neighborhood. And the crow in my neighborhood only mob the hawk. Also, if there is no nesting platforms or pre built bird of prey nests, will the great horned owls just not nest? Also, is it possible that I have long rated owls in my neighborhood? I may have heard them before, but I have a lot of dogs in my neighborhood that sound exactly like that long eared owl’s dog like sounds so I really don’t know. Also, could a great horned owl attack me if I make their sounds? Also, in Arizona, at like 5:00 PM, I heard a great horned owl, I found it in a tree and stood under it and kept hooting at it. Even though it knew I was a human it still was hooting, though not at me. It would also look down at me and hoot every now and again. Eventually, there were like five people staring at it from right next to the trunk. Was this owl getting overwhelmed? Also, right next to a busy street in my neighborhood on the side walk, there was a squirrel without a face and crows were surrounding it. The squirrel didn’t look like it was hit by a car, and other that having no face, it showed no signs of injury. Could an owl have done that? Or a hawk?

    ReplyDelete
    Replies
    1. Since you are so interested, I suggest you learn how to use eBird. Then you can see all the owl sightings (and all other birds) near you, including at nearby parks.

      See my eBird tutorial:
      https://www.whatbirdsareinmybackyard.com/2019/12/what-birds-are-in-my-area-ebird-tutorial.html

      Delete
    2. Thank you! I have eBird and I have an app called Birds Near Me, and the closest owl to me on the app is a great horned owl a few miles away. I am asking a lot of questions because I am worried that the owls in my neighborhood were stuck with this as their territory, and are struggling, and I would like to learn more about if they are adapting to my neighborhood, if they can’t survive here, or if they don’t need to adapt and are perfectly fine.

      Delete
    3. Owls have large territories. Great Horned Owls are quite successful and live near people or in wilderness. It sounds like owls are only an occasional visitor to your neighborhood, probably from better habitat nearby.

      Delete
    4. I had three owls in my hard last night. They were so loud they work me up. Normal hooting but every once and a while one sounded like a howler monkey. It was a sound I never heard in person and was like what type of wild beast is out there. Is it the male that calls out for the female when its time to mate or the female that calls out to the male to start the mating?

      Delete
    5. Owl rookie,

      How exciting! Both males and females call (the larger female with the deeper call). They get quite excited at times. Not sure where you live, but if in the East or NW forests, listen to recordings of Barred Owls. They also make quite a racket!

      Listen here
      https://www.allaboutbirds.org/guide/Barred_Owl

      Delete
  6. Hi Greg, Thank you so much for this article! This past week two great horned owl babies fell out of their nest which was in a tall pine tree near our house. We didn't discover the first until it was too late, but yesterday its sibling fell out and is now at a rehabilitation center. I want to build a sturdy nest for them for next year but our biggest ladder is 15 feet and their current nest is over 30 feet up. Do you think they will use a nest that is toward the lower part of the tree where there are fewer branches? If the nest should be higher, do you think they would use it if we built it on a pole and placed the pole adjacent to the same tree? Do you have any other suggestions? Thank you so much! Tracy

    ReplyDelete
    Replies
    1. Wow, Tracy, what an adventure you've had with the owls.

      It is possible that the owls will use some kind of shelf down lower next year. Or, they may try again from the spot they selected this year. Younger parent owls sometimes fail at their first nest.

      Delete

Thank you so much for visiting! Would you please leave a comment to let me know what you thought and how I can make this resource better for you?

--Greg--

Legal Disclosure
As an Amazon Associate I earn commissions from qualifying purchases.

Legal disclosure

As an Amazon Associate I earn commissions from qualifying purchases. Thank you for your support.

Featured Post

Hummingbird season: When to put up & take down your feeders

Many people look forward to hummingbird season. Feeding and watching the antics of these hyperactive and sometimes pugnacious birds brings m...