Answer: Owls hoot at night to warn intruders that they are in the owl’s territory. Most of them are nocturnal animals making them more active after sundown. Hooting is also done during courtship, defending their territory and communicating with their mate.
Overview
Owls are mysterious birds. Probably, this is simply because most of us never see them. Nevertheless, they have had a place in cultures and mythologies worldwide. Owls usually represent wisdom, although they also have negative connotations at times.
They are, however, universally respected as apex predators that hunt and kill in silence. It is their quietness that also means we don’t know they are there and also what makes them effective killers. But there are times when owls do call. Why? Why do these silent assassins suddenly hoot?
That is what we will be looking into in this article. So read on if you want to know all about owls and why they hoot at night.

About Owls
There are around 250 owl species globally, and they are everywhere except Antarctica. The formal name for owls is Strigiformes, which are split into two groups. The first is Tytonidae, which is made of owls with heart-shaped faces and has 18 species. The most famous and widespread of which is the Barn Owl (Tyto alba). The other family is Strigidae which holds all other owl species, most of whom have round-shaped faces.
The American Birding Association (ABA) lists 23 species of owls present in the United States. These include both the Tytonidae and Strigidae families. American owls are fascinating simply because they are so diverse. Here are some of the differences between our owl species.
- Size – The Great-horned Owl has a wingspan of 40 – 57 inches, whereas the Elf Owl measures in at a mere 13 inches.
- Habitat – The Snowy Owl lives in the cold north, right up into the Arctic Circle, whereas the Elf Owl lives near or in the deserts of the south.
- Habits – Some owls are only active at night (nocturnal), some also at dawn and dusk (crepuscular), and some are active in the day and night (diurnal).
- Ears – Some owls, like the Barn Owl, have no visible ears, and others, like the Great-horned Owl, have visible tufts.
- Vocalization – Owls make a huge array of sounds, from hooting to screaming and barking.
Owl Species
In this article, we are investigating why owls hoot. But not all of them do. However, they all use some kind of sound for communicating, so we will be reviewing why they make any kind of noise, including hoots. To begin with, let’s look at some very different species of owl found in the United States.
Barn Owl (Tyto alba)

The Barn Owl is a common and widespread owl of continental America. It is not found in Alaska but has been reported in Hawaii, as seen in the range map below. Plumage in this owl varies but note the heart-shaped face.
Although it can be seen fairly regularly during the day, it hunts mostly during the night hours. The Barn Owl is silent in flight, even at ultrasonic levels, and the bird hunts primarily by eyesight. It can also remember the noises its desired prey (usually rodents) makes and can track them by sound.

The Barn Owl’s most likely heard call is a hiss, like the recording below, but it has a good range of vocalizations including screeching and tongue-clicking.
Elf Owl (Micrathene whitneyi)

The Elf Owl is found in southern California, Arizona, and Texas. It is the smallest owl in the United States and is unusual as it is migratory, spending winters in Mexico.
As seen in the range map, it is a desert dweller and lives in any kind of brush near them. The surprises with this owl keep coming, as it is considered the most voracious raptor in its range. The diet of the Elf Owl is exclusively arthropods like spiders, insects, and centipedes, etc. It perches and waits for prey and will catch them on the ground, in foliage, and in the air.
The Elf Owl is often visible at dusk when it is calling the most.

The Elf Owl has many similarities to the Screech-Owl, including its calls. The calls of the Elf Owl usually have a purpose, like flying, copulation, and alarm raising. Below is the call of a bird in flight.
Snowy Owl (Bubo scandiacus)

The Snowy Owl makes our list of particularly interesting owls as it lives in colder, northern states, including Alaska. It is also unusual because of that incredible pale plumage.
This owl is an opportunistic hunter, as you might imagine in that climate, and will take mammals and birds. If it needs to, it will eat carrion as well. Consequently, it is fairly nomadic and has a wide territory. As this owl lives and hunts in the Arctic Circle, it is diurnal, hunting in day and night.

The Snowy Owl has a wide range of calls, including the hooting, as recorded below. It will also whistle, grunt and scream.
Northern Pygmy-Owl (Glaucidium gnoma)

A rather rare, small owl that resides on the Western side of the United States, avoiding the hot, dry areas. The Northern Pygmy-Owl is diurnal and, with luck, can be seen sitting out in daylight hours.
The habitat it prefers is forested areas at low levels and at higher elevations. It is thought that it hunts more during the day and possibly not at night at all. Like the Elf Owl, this bird might be small but fierce as it hunts mammals and small birds.

The Northern Pygmy-Owl call consists of a noise recognized as ‘toots’ in a quite delicious manner. It calls most at dawn and dusk.
Great-horned Owl (Bubo virginianus)

The Great-horned Owl is the most common owl in continental America. It can be found in forested areas as well as more urban areas. This owl is incredibly adaptable, surviving and thriving in the cold north and hot south.
The Great-horned Owl is nocturnal but can be seen at times in the day. When hunting, it perches and waits for prey, using (as you would expect) its superb low-light vision. The diet consists of a wide range of animals, from scorpions to larger mammals and even larger birds, including herons.

The Great-horned Owl has a wide range of calls and sounds, but the most common is the single note hoot and an occasional bark.
Burrowing Owl (Athene cunicularia)

The Burrowing Owl is resident in open grasslands, commonly in the west of the U.S. but also along the Eastern Seaboard and Florida. It is famed for the humorous photos of it as it goes about its business. As the name suggests, it lives in burrows underground and is active day and night. It feeds mostly on insects but will also hunt small mammals.

The Burrowing Owl has a wide array of calls, including the unusual clapping sound below.
Western Screech-Owl (Megascops kennicottii)

This is another small owl with gray plumage. It looks a lot like the gray morph Eastern Screech-Owl, and although they appear similar, they are distinct in range and have very different calls.
The Western Screech-Owl is a common resident of forests and wooded areas from the warm south to the temperate north. It feeds on a wide variety of animals, from as small as insects to mammals and birds. It likes to hunt in riparian locations and will wait at dusk for crayfish to emerge.

The Western Screech-Owl has fewer vocalizations than other owls, and researchers consider most of these to be just variations of the bird’s main hoot-based call. The recording below sounds like a barking variation.
Types of Owl Hoots
So, we have established that owls come in all shapes and sizes, live in very different climates, and make different sounds. It might be considered that owls have an easier time of it as they are mostly active at night.
There are less dangers (particularly as humans are generally asleep), less distractions, and fewer irrelevant creatures around. Thus, they can focus on what is important: hunting, courting, nesting, and bringing up chicks in safe territory. These factors are all reflected in the owls’ communication methods.
As previously stated, owls have other calls than just hooting and for our purposes, we do not discount any of them.
Here are the reasons why owls call at night.
Territory Protection
While owls may have the night skies mostly to themselves, there are a lot of them, and they all need a place to call their own. Owls need territory in order to mate and nest. Also, owls generally like to stay in the same place, so once a territory is established, they will defend it aggressively. It is usually the job of the male to claim and defend a territory, allowing the female to court and mate.
Identifying territorial calls is difficult for researchers and audio recordists. Distinguishing between general song and territorial marking is not easy for most species. The Great-horned Owl, however, has been studied, and it is known that the male will make repeated territorial calls during the courting and mating period. The calls are deep and can carry for long distances through the territory. They are matched with an upright, strong posture by the owl. Even these songs are not identified as territorial by those recording them.
Below is a recording of a Barn Owl in flight, which is the closest example of a territorial call we could find.
Courting
Courting calls may be associated with territorial calls. Owls need to make sure no other male is coming into his patch while at the same time advertising for a female. Calls will tend to be softer and more reassuring to the female, even whining at times.
The male Western Screech-Owl, for instance, will begin calling in late winter. It positions itself by the nest and hoots to the female with the calls increasing in intensity. The vocalizations change to a softer, more subdued sound as the female accepts his courtship offer. This kind of advertising call is common amongst owl species as the males try to attract a mate. Below is a recording of a male in courtship.
Copulation
It is not unusual for owls to communicate with each other during copulation. The female, in particular, may give out a specific call at the end of the process. Below is a recording of a female Elf Owl.
Duets
Once a male and female are paired during courting, it is important that they bond. One of the ways they do this is by duetting. This may be done at the nest or within the territory as they hunt. The Elf Owl, for example, duets with the male taking the lead. The female will copy him using a softer tone.
This is a pair of Great-horned Owls communicating with each other.
Bonding with Chicks
We have all heard the plaintive chirping of young chicks, and owlets are no exception. It is their way of ensuring their needs are met. Some adult owls will gently call to the eggs to encourage them to break out of the egg, and the chicks begin peeping very soon after hatching. As they grow, so does the volume. Once the youngsters have left the nest, they will continue to beg for food for some time.
Below is a recording of a female Snowy Owl in the nest with young chicks.
Alarm Raising
All birds have alarm calls, and most species take note of other kinds of birds if they are raising the alarm. Owls are a little different in that there are not many other birds around during the night. Also, they are apex predators, so not much cause them danger, you might think. However, not all our owls are large. The smaller owls are in particular danger from other owls. Hawks and eagles may also hunt at night and take unsuspecting owls.
Owls active in the day are particularly vulnerable, and none more so than the ground-dwelling Burrowing Owl. Predators like wild dogs, feral cats, or birds of prey will make short work of these little owls. Below is a Burrowing Owl making an alarm call.

Conclusion
There are probably more owl species and individual owls in continental America than you imagined. As we generally don’t see these nocturnal beasts, it is always a bit of a surprise when we do. We are more likely to hear owls calling at night.
While we associate owls with hooting, that is not the only noise they make. From barking to screeching and clicking, owls have a vast repertoire of calls. And like humans and other animals, they use tone, volume, and language to communicate with other owls and animals. And also, like other animals, they also communicate to ensure their needs are met. That may be a chick needing to be fed, an adult male establishing territory, or a female in copulation. Owl communication certainly reflects the circle of life.
I recently saw a Barn Owl during the day, and I was astonished and delighted. I didn’t actually see the owl at first; just an incredible commotion in the trees. As I went to investigate what was going on, I then saw the owl (pictured above). The cacophony was from a collection of smaller birds trying to get the owl to move on. The owl was silent, but it couldn’t hide from the other birds in the daylight. My tips for seeing owls are always investigating owl-like noises at night and a group of screaming birds during the day.

Related Questions
Do owls talk to each other?
We have already answered this, but another interesting point is that bonded pairs of owls may develop their own language, especially to communicate. How romantic!
Do owls always hoot 3 times?
I think this is a bit of a myth. The hooting is probably a territory marking and might be a 3-call repeat.
Where do owls live during the day?
Owls have a range of places to go during the day. They may actually be out hunting still. If they are roosting, then they could be sitting in trees. That’s why it is always a good idea to look up in the forest. Many species that nest in tree cavities will roost in there as well, and of course, if there are eggs, the female will likely be sitting on them.
What time of year are owls most active?
Owls begin the mating process early in the year, so begin looking for them from late January onwards. If you can brave the cold, that is!
What is a group of baby owls called?
Baby owls are called owlets; a group of owlets is called a brood.