  The Question: From time-to-time, birds fly into our picture windows and die. On two occasions, once last summer and then again just two days ago, a squirrel or a chipmunk retrieved the carcass and proceeded to devour it. This seems to be unusual behavior, and I wonder what triggers it, or if it happens more often than I am aware?Submitted by: A. C., Georgia, USA |
The Short Answer: Like most people, I once thought of rodents as seed eating herbivores, but it turns out that many, if not most, rodents are really omnivores that will eat insects or meat whenever they can get it. Gray squirrels (Sciurus carolinensis) and eastern chipmunks (Tamias striatus) are known nest raiders that will eat eggs or chicks. They also occasionally kill and eat adult birds. And gray squirrels are commonly seen eating road kills. So the answer to your question is that this carnivorous scavenging by a gray squirrel and a chipmunk is not unusual behavior at all. Great photos, by the way!
More Information: Scientific reports of predation by rodents list gray squirrels as eating other gray squirrels and birds. The list of observed prey for chipmunks also includes birds, as well as other chipmunks, voles, snakes, frogs and salamanders. Surprisingly, even small mice are significant predators of birds, mostly eggs and chicks, but they occasionally kill adult birds as well.
Given that squirrels and chipmunks are such frequent nest raiders, you might think that adult birds would defend their nests against them, but adult birds often simply abandon a nest if a squirrel comes near. This may be because, as mentioned above, squirrels are capable of killing adult birds. Under such circumstances, it might make sense for adult birds to simply give up and save their own lives in the hopes of nesting again in the future – especially under conditions where if the adult bird is killed while defending the nest, the chicks aren’t likely to survive anyway.
So, now you are going to have to view squirrels a little differently. And those cute little chipmunks are actually pretty good hunters. In fact, one study showed animal matter in the stomachs of 75% of chipmunks examined.
And all of this gives a new perspective to the Rodents of Unusual Size (ROUSes) that feature prominently in the satirical fairy tale movie, The Princess Bride. Turns out they are just imitating their relatives of usual size.
Sources:
CALLAHAN. (1993). Squirrels as predators. The Great Basin naturalist, 53(2), 137-144.
LANDRY, SO. (1970). Rodentia as omnivores. The quarterly review of biology, 45(4), 351-&.
Bradley, JE, & Marzluff, JM. (2003). Rodents as nest predators: Influences on predatory behavior and consequences to nesting birds. Auk, The, 120(4), 1180-1187.
Pietz, PJ, & Granfors, DA. (2005). Parental nest defense on videotape: More reality than “myth”. Auk, The, 122(2), 701-705.
Lima, S L. (2009). Predators and the breeding bird: Behavioral and reproductive flexibility under the risk of predation. Biological reviews, 84(3), 485-513.
Many thanks for the research, Tom. If someone had told me about this without pictures, I likely would not have believed them.
To (badly) paraphrase a famous writer: There are more things in this world than are dreamt of in our philosophy…
ACB
I once witnessed a really ferocious chipmunk battle over a massive frog carcass, and thought that the two involved must have been really vicious, street-hardened chipmunks. Glad to know that it’s not the case!
It is interesting that we don’t expect such behavior from these cutesy little guys – I bet that’s how they manage to sneak up on prey. The frog thinks, “Aw… look at that wee little chipmunk. Let’s feed it some br-” and BAM. No more frog.
Or, you know, something like that.
I was horrified today to see a chipmunk dragging a robin across my deck. I noticed because oodles of birds came dive bombing and pecking the chipmunk to drop the robin. At first it was about 5 robins, then a cardinal, a yellow bird, an oriole and then even chickadees stood by and watched. The chipmunk got away. Unfortunately the robin somehow in the scuttle fell off the deck and haven’t seen it, I believe it was dead.
Wow. That’s interesting. I wish we had a video of that.
I just saw a Chipmunk raid a cardinal nest and take an adolescent chick across my deck. I am not too happy about this. I wondered why the cardinals had been so crazy all day.
I saw a chipmunk attack a sparrow under the bird feeder. It would also hide under the low blue spruce branches in ambush. I also saw it run off another chipmunk. One day we found 3 dead sparrows and one large mouse under that tree. At first we thought something was wrong with the feed but did suspect that aggressive chipmunk. My son thought something was wrong with the chipmunk. We never saw them agressive before.
Was horrified to see one of the chipmunks attack a sparrow near the feeder. I went out to retrieve the bird and it was gone. Don’t know if the chipmunk dragged it away. Solves the mystery of another dead bird we found last week in the same spot.
While hunting in the Blue Mountains of Oregon 09/24/2015 I observed a Chipmunk eating a mouse. When I scared it away, rigor mortise had not yet set in. Did he also kill it??
Tough to know. It’s possible.
My daughter and I had a mouse that got caught in a waste basket of our barn. We decided to set it free in the woods (neither one of us has the heart to kill it). When we set it free, it went running off happily only to have a chipmunk run after it and kill it. It picked it up and spun it around like a nut while biting it and then ran off with it in its mouth! We were so shocked we just stood there with our mouths open. The funny thing is there was a second mouse that slipped out of the waste basket and hid under a leaf. We didn’t blame him.
Wow. I have not heard of that kind of direct predation. Thanks for sharing that.
Just watched a grey squirrel climb a 15′ steel pole to get into a Martin house in winter. The house had 24 rooms and the squirrel checked each for a meal. It found a dead bird carcass which it took back to its nest for a snack.
Was in my kitchen this morning when a female cardinal bounced off of one of the windows. Went outside to check on her and she was standing motionless with dull eyes, obviously dazed. Didn’t want to frighten her so went inside to watch her where I didn’t think she could see me. A couple of minutes later, a chipmunk approached her from behind, put a paw on her back and moved its head toward the bird’s head. Not knowing the chipmunk’s intentions, I shooed it away. I kept watch over the bird until, after a few more minutes, her eyes became alert, she moved her head around and then flew off. Had to shoo the chipmunk away twice more before the cardinal had recovered enough to take flight. Later Googled chipmunk predation and found this string of posts. I knew chipmunks would take a chick but hadn’t before considered they would go after an adult cardinal. So I’m glad I kept watch over the bird until she was able to fly again.
Holy crap. I was surprised to see prairie gophers (not “prairie dogs”) engaging in road-kill cannibalism.
I had recently become curious about whether other squirrels would eat meat as well … I guess now I know. The chipmunks are surprising, didn’t think they were that aggressive. No wonder they can be such bold little guys!
I came upon this site because I thought squirrels were herbivores and couldn’t believe it this morning when I watched a squirrel chowing down on a blue jay in my backyard! I was afraid that something was wrong with it like perhaps rabies! Lol Good to know it’s “normal”. I’m thinking that’s one tough squirrel to take on a blue jay!
Today I was really shocked to see that a ground squirrel entered my diamond dove pin I have like 30 of them and bit her head off and when I went to retrieve the rest of her that was left the squirrel pulled her in the hole I was shocked and scared so that being said I have to put all my doves in another secured cage with wiring all around and under them.
This morning I watched a crazed chipmunk attack a bird in my local park. The chipmunk was not afraid of me when I approached. When I later returned, the chipmunk was gone, and so was the bird’s head. The whole scene felt like the beginning of a zombie movie. Glad to see it’s quite normal, if horrifying.
I am a bird lover and we have lots of mature trees in our yards. Two days ago the Blue Jays were making a big racket, so I figured the squirrels were out stealing their chicks, or maybe my old cat was laying in the shade. But then yesterday morning, my husband found a headless jay, on the ground below one of the trees in the backyard. I thought maybe a big ol’ rat got to it during the night before, but now I know for sure the two squirrels working their nesting area, decided to off the noisy one. Just fuzzy rats is all they really are to me. Kinda cute compared to ugly, giant Roof rats. Now I hate them, too.
Wondering if the 1.5″ holes in the 2 new bluebird boxes that I bought today, will make them safe for the bluebirds that I hope to attract. Our back yard is visited by a couple of squirrels on ocassion, with squirrel-proof birdfeeders available to the birds and some spillage available to the squirrels! We’ve never witnessed any “bird murders”, but now I wonder if the bluebird boxes should be nixed!? Any suggestions would be greatly appreciated.
Hi Dan, Sorry for the delay in responding. 1.5 inches seems to be the standard for bluebird boxes. Do you have the bluebird boxes on poles? Can you squirrel proof them with the same techniques you used for the birdfeeders? I think 1.5 inches would exclude squirrels. But sometimes squirrels will chew the holes wider and then get in. Tom
I came across this site because I taught I saw a squirrel running up a tree with a red cardinal in her mouth. This is so horrifying,
people watch your kids!!!!
Today, saw a California Ground Squirrel attack, kill, and start eating a fence lizard. It disposed of the legs and tail and dropped the lizard when disrupted by another ground squirrel. I did not see if it returned to the kill to finish it.
I have been observing a Robin nest out my window for the last week. The mother is sitting on eggs. Three times I have seen squirrals try to approach the nest and all three times either the female or both Robins aggressively attacked the squirrals. They have also deffended the nest against Bluejays and Boat Tailed Greckles. A very protective pair of parents to be.
Helen, that’s very interesting that you witnessed that. I have not actually seen that before. Getting baby birds to the point of flying is no easy task! Tom
I had two robins nests, one above the deck and one on the beams below the deck. The one nest below the deck, was raided by squirrels and the baby’s were killed and eaten. I’m fighting a losing battle as I speak of a persistent black squirrel with a red tail continues to harass the second nest. I chase the squirrels off the deck on a daily basis and I’m wracking my brain to think of a way to protect the second nest from the squirrel.
Additionally there was a nest of Nuthatches in the mountain ash outside my front window that the squirrels raided. Baby nuthatches were not eaten, they were torn out of the nest and dropped to the ground where they died..
I was devastated as were the poor parents that tried desperately to save their chicks.
Squirrels “are” carnivorous.
Hi Marylee, I appreciate your efforts to protect the nests. If you are unsuccessful, you might take some consolation in the idea that the squirrels are feeding their own babies. Robins and nuthatches are also carnivorous, of course. It’s just that they eat mostly insects and invertebrates. Tom
Yesterday and this morning we notice a big commotion with the Robins around a Star Magnolia bush. Yesterday a squirrel came out of the bush with a baby robin in its mouth. Today the squirrel had another baby in its mouth and I noticed 2 babies out in the lawn around the bush. I put one baby back in the nest and he immediately jumped out of the nest and fell to the ground. Yep, squirrels do eat meat! This afternoon there are no babies to be found. Never realized that squirrels will eat birds and other small animals, until today when I read your post and all the comments and seeing it with my own eyes! It is survival of the fittest in the big out doors! Sad to see the babies being eaten. But, like Tom said, the predators babies need to eat, too.
Yikes! My very protective Robins finally caused the squirrals to give up but today the 2 baby Robins were old enough to jump from the nest. They hung around for a bit then vanished. I assume into a bush or undergrowth. Both parents are sticking very close and mom is the most aggressive defender of her babies I have ever seen. I do hope the babies make it as the next couple of weeks they are so very vulnerable. Will keep you posted.
Update: One baby Robin made it to maturity. I believe I read some place that one making it is the more common case. I did see the squirrals trying to get them under a bush but then the baby that survived I noted had moved under another bush and in lower branches of a pine tree. I suspect the squirrals got the other one. It was nice to see the other grow and mature then fly well. Now its as good at flying as its parents. Knowing nature I would say this was a success story. On another note I have convinced my neighbors not to use pesticides on their lawn as it kills worms and other grubs eaten by birds. In most cases they said they just had not thought about the unintended consequences that could come from use of pesticides.
I live in west Michigan where I recently moved and have a problem with a large squirrel getting in my bird feeder despite my best defenses so I keep an eye out my back door with a BB pistol to try and discourage this behavior. The small ones can’t get in. Saw the large squirrel today that hadn’t bothered the feeder lately on the fence post voraciously devouring a medium sized sparrows body from the head down. Never considered squirrels carnivores in this way so lots of great info on this site. Guess he/she is already full enough to leave the feeder alone.
today morning saw my budgies net where 1 budgie was dead 3 were missing, found out it was squirrel work. really wanted to kill those squirrel but it was my mistakes to kept small gap in the nest for them to fly out and come my bad and still regret. really very sorry budgies hope i will be forgiven.
Today I saw two Sparrows racing around and hiding under my lawn chairs. I wondered why. I then saw a big,grey squirrel eating another one!! So the first two were obviously scared and therefore hiding! I thought I was seeing things,until I saw the legs and feet of the bird,sticking out of squirrels mouth!! I do have a bird feeder out there,but today it was empty,so I guess the squirrel made do,with a bird?!?!
I was working on liner for our pool and found a nest with 4 chicks in it. I did not want to disturb then but they would have fried in our unusually hot May here in SC. So I moved the nest and placed it in a crook of a Oak tree thinking mama bird would find them. Went to check on them, and saw a grey squirrel by the nest and no chicks, that is what led me to this site. Had no idea that squirrels were meat eaters.
Hi Joseph, sorry to hear about that. Tom
I live in England and I’m such an animal lover I feed everything in my garden. I have 4 squirrels that come to feed and loads of bird’s for the last 6 months they have all been eating together & share the food . Do birds and squirrels get to know each other in home garden’s. I would hate to think the squirrels would hurt the bird’s . I just bought 2 new bird houses I was going to put them on the tree but the squirrels are always running around the tree . Where’s best place to put it do you think. And if I keep them all well fed hopefully no birds will get hurt few of the squirrels take the monkey nuts from my hand do you think these are more friendly best wishes Tracey
Yesterday I watched a squirrel have a battle with a small snake and then a bird which looked like a dove from the distance. The site was up on a roof, inside a small duct which ran across the length of the house. Families of squirrels have been seen over the past year, raising their young in this duct. My husband and I have greatly enjoyed watching them. However, what we saw yesterday horrified and amazed us simultaneously. We observed the fight for prey, at the end of the duct, which is across from our kitchen window, where we frequently watch the young squirrels who sun at the duct’s opening The squirrel yesterday was first sunning, then seen wresting with the small snake, then suddenly the struggle with the dove began. I was fortunate enough today to find this site which explains part of our observations. Thanks for the information.
There is a chipmunk that lives in my front yard. A couple days ago I looked out and saw her (she has teats which I saw with my zoom lens) sitting on a patio chair holding and eating a decapitated Western Fence Lizard (aka Bluebelly Lizard). That was a surprise!