Have you ever noticed when you hear a group of crows cawing & making an awful racket in the woods, there’s often an owl at the center of those mobbing birds? It’s a pretty amazing thing to see!
In fact, if you know to listen for these crow mobbing calls, it’s one of the easiest ways to find owls in the woods.
But it also brings up the question of why crows attack them so intensely?
As a general rule, crows attack owls to reduce their risk of predation. Owls do sometimes eat crows and they frequently have overlapping nest habitats which puts them in close proximity.
However, if you watch this behavior for long enough it becomes apparent that crows are expending an incredible amount of energy attacking owls.
It also sometimes seems like they’re putting themselves at risk by coming so close to a dangerous predator, and yet the owls don’t really seem to react all that aggressively.
So what’s really going on here?
- How does crow mobbing work?
- Do crows ever cause harm to the owls?
- Why don’t the owls fight back?
- How often do owls eat crows?
- And aren’t the crows taking a big risk by mobbing them?
There’s a lot to unpack, so let’s explore these questions in more depth…
What Is Mobbing And How Does It Work?
Mobbing is a common defence strategy used by crows and other songbirds to overwhelm and confuse predators like owls, hawks or other dangerous animals.
Mobbing looks like a group of birds all crowding around the danger, calling & even dive-bombing it. If the owl flies away, mobbing crows will often pursue and chase the target in a dramatic aerial battle.
This behavior is surprisingly common & easy to identify with the study of bird language. In the case of crows & owls, mobbing looks (and sounds!) like this:
As for why this anti-predator strategy works, some of the most informative research on this topic was published in an article called effects of avian mobbing on roost use and diet of powerful owls.
This study measured how often various bird species engaged in mobbing owls, compared to how often these same species were predated by those owls.
They discovered some very interesting things:
- Birds who engage in mobbing owls are much less likely to be targeted for predation by those owls.
- Birds that do not engage in mobbing owls are much more likely to be targeted for predation by owls.
So by preemptively mobbing owls, crows reduce their overall risk of predation.
It’s a way of driving predators out of the area before they become a threat (and also has the interesting side-benefit of increasing fitness level in birds doing the mobbing).
Of course this strategy doesn’t come without some risk, so the question still remains of just how dangerous are owls to crows?
Let’s take a look at this next…
Do Owls Eat Crows? (Assessing The Risk of Predation)
It’s well documented that large owls like great horned owls do sometimes eat crows (study), but overall this only makes up a very small part of their diet.
In general, owls are much more likely to eat small mammals like voles, chipmunks, squirrels & even rabbits, with only rare attempts at hunting birds when the opportunity is present.
So then why do crows care so much about owls?
Well, it’s a bit of a chicken and egg situation because given the right opportunity an owl certainly would eat a crow!
However, it’s very likely that part of the reason why crows don’t get eaten more often is because this mobbing, chasing & attacking strategy is such an effective defence.
There’s simply no way of knowing how often owls would hunt crows if they weren’t being pre-emptively attacked.
What we can say for sure is that crows are some of the most social & aggressively territorial birds on the planet.
Crows are particularly skilled at using strength in numbers to overcome the risk of predators like owls. It’s one of the reasons why crows gather in such large groups.
Which Types of Owls Get Attacked By Crows?
In general, large owls like great horned owls, barred owls or great gray owls are the most likely to be attacked and chased by crows. Large owls include species like:
- Great Horned Owls
- Barred Owls
- Great Gray Owls
- Blakiston’s Fish Owls
- Snowy Owls
- Eurasian Eagle Owls
(And by the way… If you observe crows mobbing other types of owls not mentioned here, please let me know in the comments and I’ll add them to the above list!)
On the other hand, small owls are very unlikely to be bothered by crows because they simply don’t pose a big enough threat. Small owls can be incredibly tiny and include species like:
- Pygmy owls
- Saw-whet owls
- Burrowing owls
- Elf owls
Aside from the size of owl, there is one other behavioral trait that likely affects how often they get chased and attacked by crows, and it has to do with their nesting strategy…
Do Owls Steal Nests From Crows?
It’s well known that owls are not very sophisticated nest builders. As a result, it is extremely common for owl species to use old crow nests when looking to raise a family in spring.
In fact, a particular study of 104 pairs of Long-Eared Owls in Idaho noted that every single nest used was original built by corvids (the crow family).
That’s pretty darn conclusive! And it means that not only do owls frequently share an overlapping habitat with crows, but everything down to the exact nest placement and species of trees can be identical.
This is NOT to say that owls steal ACTIVE nests from crows, but rather they will commandeer abandoned nests built in previous years.
An overlapping nesting niche is one of the key predictors of territorial behavior that I covered in a separate article on why birds fight, so definitely read more on that if you’re curious about this.
The basic idea is that anything in close proximity will be more likely to bump against each other, and it’s very likely this contributes to the tendency of crows to attack owls so vigorously.
Of course, most of our exploration has focused on the danger owls pose to crows, however it’s also a worthy idea to explore how much danger the crows pose towards owls!
Will Crows Ever Kill Owls?
As a general rule, crows do not kill owls during these chase, mob and attack events. The primary purpose of mobbing is to intimidate, annoy & generally make life difficult for them.
That said, it is technically possible for a group of crows to do significant damage to owls that could result in death.
In my research for this article I was unable to find any documented instances of crows killing an owl, however there are anecdotal reports that it has happened.
Based on my own personal experience of watching owls being mobbed, I suspect it’s probably more likely that a crow would be injured or killed during the mobbing than the owl.
Certainly in the case of hawks there are rare documented cases of backfired mobbing attempts.
It’s very informative to consider that crows are still willing to take this risk in order to reduce their overall risk of predation from the owl.
Over the years, I’ve spent hundreds of hours watching dozens of different owl mobbing events, and I’ve never witnessed any injuries to either the owl or crows involved, so my instincts tell me this is rare.
So now you know pretty much everything there is about why crows attack owls. I’d love to hear your own crow & owl battle stories!
Brian Mertins, your nature articles and observations are excellent and I’ve followed you for a few years…Here in Florida in an oak hammock, I don’t have many crows stopping here. Blue Jays take that role here as well as other small birds chime in. And not just owls, hawks too. When I hear blue jays loudly calling together like your video on the crows, I know a hawk is lurking by…usually when the blue jays persist and gather all the birds to chime in, the hawk like the owl eventually leaves. The bravest bird I saw was a little Blue-gray Gnatcatcher who also joined in and eventually worked its way around to the top of the tree and attacked the red-shouldered hawk’s head top with it’s sharp bill, not once but thrice and the hawk finally left the bare tree where he could see all prey from afar.
Thanks for sharing Juanita! It sounds like an amazing spot to explore!
Thanks for your expert observations, Brian, always a pleasure to read!
I recently saw a crow trying to pull a weak gull out of the water. The young gull (was well, gullible! in that it) seemed to frequently approach the crow on the edge of the water and beckon with an opening mouth (asking for food, or a sign of bird flue?). The crow pulled at its wing, held it down on the embankment and then proceeded to pluck out a few feathers (or was it trying to get the gull out of the water?). Eventually, the crow pulled the gull out by its own beak and then held it down while it pecked its head. I called the animal ambulance and they reported that the gull subsequently died, unknown cause. Was the crow trying to kill the gull? I know this particular crow and it dislikes gulls, often dive-bombing them on the water or chasing them in the sky. Do you have any ideas of what was actually happening, Brian?
Hi Maaike, great question! Crows will attack gulls in much the same way they go after owls, hawks & eagles. Around water they have shared habitats and likely also eat many of the same things.
I heard a story years ago from someone who observed a crow dive bombing a seagull over water until the gull fell into the water and eventually drowned. I would suspect based on your description that you caught the ending of a dive-bombing encounter.
While I am here, Brian, I have another question. There is a crow who lives opposite me and it seems to have a fascination for the water’s edge. It spends a fair amount of time staring into the water, walking or hopping a further 30cm and then approaching the edge of the lake again to stare into the water. It does this for at least an hour a day! We are going into summer here in the Netherlands – is there a food source I am unaware of, or is this a case of narcissus?
It’s a very interesting behavior! In general, there is always a good reason for why animals do the things they do. Sometimes it just takes a bit of good tracking to figure it out.
I would suspect a food source, but crows are also known to be attracted to shiny things like stones or coins or little trinkets, so it could be some kind of gathering activity. Apparently crows have also been observed looking at themselves in mirrors, so it could be the reflection.
How many days has this been going on for? If possible, I might suggest going down to the water’s edge and looking for yourself to see whether you can find food or shiny things, or how clear the reflection is at this spot. Is the wind usually calm when this happens?
Thanks Brian, I will go and inspect the areas that he patrols and see if I can see anything in the water. It has been going on for at least a few weeks, since we hit Spring weather here in the Netherlands.
Brain,
I just wanted to let you know how much I enjoy your articles and learning more about the birds in our backyard. Thank you for including pictures and sound bites, to help clarify bird behavior.
MKB, Magnolia, TX
Thanks! Glad you enjoy it!
Thank you for this helpful information! I found your page while researching why crows surround and caw at owls.
I was working at home recently and heard a very loud crow ruckus in our back garden. We went outside to see what the fuss is about and saw a large owl in a tall tree, staring at our young cat in the garden. There were about 5-7 crows in the surrounding trees putting up a huge fuss over this owl.
We quickly picked up our cat and thanked the crows for making enough noise to (inadvertently) bring our attention to the danger for our cat. She was in a small enclosed area in our garden, so she would not have been able to easily hide or escape.
Thank you again for this helpful information
I woke up this morning and heard the birds squawking. Came out and captured this exact situation. I’ve taken video but can’t upload. They have been going at it for almost an hour. That owl is simply stoic. It’s amazing!!!
Today a great mob of crows were making a great racket in the trees at our house. Usually I see them chasing hawks away but today was different. After they flew away there was large dead owl under the tree.
Wow that’s crazy. Thanks for sharing this story.
Great article Brian. We just witnessed crows mobbing a barn owl here in San Francisco. Quite the rowdy affair!!
We have an great horned owl with one owlet, living by the bank of our river. The owlet fell out of the tree, and after getting advice from a wildlife rescuer, we renested the owl in a laundry basket (!) with plenty of sticks and pine needles and mom and baby are doing fine. We hear the owlet chirping and squawking in the tree. We saw the crows mob and dive bomb the mama, and she was on the ground at the rivers edge, but then she flew straight into them and they dispersed. Thanks for a great article explaining this crazy scene! Would the crows ever bother the owlet?
It’s a good question… given the right opportunity I think crows would probably bother an owlet.
However with the parents present it’s unlikely they would ever get that opportunity. I’ve certainly never seen it or heard any reports of this happening.
I suspect the adult owls would always take priority of attention because that’s where the real threat lies.
On several occasions I have seen a murder of crows mobbing the barred owl in the trees behind my house. One of the barred owls lived behind me and it’s mate behind my neighbors house.
Just a week ago, at my best friends house, she has 3 Barn Owls that live in her barn. We seen 3 or 4 crows mobbing one of the Barn Owls.
Yes! Mobbing behavior is incredibly common once you know what to look for!
Recently near my home an owl i being mobbed everyday by the crows… & I am very concerned for the owl… Its an young owl
Owls are extremely resilient, so it should be fine in the vast majority of cases. Annoying… but situations like this are just something that all wild animals in a survival situation have to deal with. It’s amazing how wild animals learn to deal with stresses that would drive us humans crazy!
You have no idea how much I appreciate your knowledge of why hawks attack owls. For the last 7 months, I’ve had an owl sit in my palm tree for approximately 3-5 mornings/month and getting harassed by VERY loud crows! I climb out of bed numerous times each morning and chase them away. By doing this, am I encouraging the owl to return every month? My heart is breaking for this poor “bullied” owl!
It probably doesn’t make much difference to be honest. Owls are pretty resilient and it would take more than a little crow harassment to make them abandon a favorite spot.
I would however, be VERY cautious about acting aggressive towards crows. Crows can hold a grudge and even pass along their dislike of individual humans through generations. You don’t want the crows to start mobbing YOU, so I would recommend letting nature unfold as it does 🙂
Thank you for article. The crows have been extra noisy the last few mornings and today I looked at the tree that they seem to be cawing at and indeed, there was an owl. The owl left, the noise stopped, but then the owl came back and of course the crows did too. I was taking a few pictures but then worried that the owl might also be protecting their young and might dive at me. Do owls attack humans?
There have been cases of large owls like great horned owls attacking humans if they get too close to an active nest. I think this would be pretty rare though.
I’ve been very close to owls with young on many occasions and they’ve never shown any signs of aggression towards me. I would recommend watching their behavior and simply give them space if they start to get nervous (this is good practice for all wildlife).
Most of the time, owls are quite happy to be observed and will stay relaxed while you take photos.
I hope that helps!