The crows in our backyard only admired our suet feeders for a long time then finally decided they were ready to taste it.
Crows (Corvus brachyrhynchos) Are Protected
Crows . you can't get rid of 'em, and you can't shoot 'em. Why? Because luckily they are protected under the federal Migratory Bird Act of 1918, which makes it illegal to harm one or destroy an active nest. If you are among those who love them, sorry, but it is also illegal to have one as a pet.
Our backyard murder (a group of crows is, indeed, referred to as a "murder") of about 40 crow visitors are about as close as we could come to having crows as pets. We could set our morning alarm by them, as they arrive (give or take about five minutes) promptly at 7 a.m. every day looking for the food we put out for them. Why do we feed them? Because they provide us, every morning without fail, about an hour of fun entertainment as they explore everything in every corner of our yard.
The crows were shy when they first began visiting but have become brave over the past few months, eating peanuts only a few feet from our bedroom window where we watch from the comfort of our bed.
Boiled Eggs Are One of Their Favorite Foods
The look in this crow's eyes says it all. It is not about to share this boiled egg with anyone.
Crows Are Intelligent, With a Memory Like an Elephant and Eyes Like a Hawk
We know first-hand that crows are intelligent, and although they don't like to share their food once they have it, there is always a sentinel looking out for predators as others eat. The natural enemies and main predators of crows are hawks and owls, and although we've never witnessed an owl in our neighborhood, there are several hawks that visit our yard regularly.
Larger hawks will attack, kill, and eat them during the day, and owls will attack them at night when they are on their roosts. Mobs of crows, however, have also been known to attack hawks and owls but not to eat them. Often, an attack by several crows is enough to drive a potential predator out of the area. For the crows, it's all about survival.
Crows can remember the faces of the people who are good to them as well as those that pose a danger, so remember that the next time you try to drive them out of your yard. Although uncommon, there have been reports of crows attacking people who have posed a threat to them in some way.
Are They Willing to Share?
When a crow discovers food, it will perch somewhere nearby and caw loudly until others come leading one to believe that they are willing to share food with others. The truth is, however, that they are more calling for reinforcements than anything else. Once other crows arrive, they begin eating the food and that's when the willingness to share ends. Crows, once they have a bite of something tasty, will either fly away to eat it in peace or eat it where they found it, fighting off any other crow that tries to get near it.
We have put food out for the crows in many different sections of the yard, and they are always able to find it. A single peanut could be hidden among the small pebbles in our yard, and it's discovered immediately. If they have found food under rocks in the past, they will continue to move the rocks with their beaks to check underneath them for treats.
Food They Love
We have found that crows love cooked pasta, boiled eggs, and peanuts more than any other food. They will eat popcorn, but only after they've made sure that none of the aforementioned food was available to them. They also eat sunflower seeds and suet, as you can see from the photographs.
© 2019 Mike and Dorothy McKenney
Mike and Dorothy McKenney (author) from United States on February 25, 2019:
This is something else that is interesting: We bought one single ear of corn yesterday, shucked it and put it outside. They pecked it until it looked like a human had eaten the whole thing. Apparently, they like raw corn on the cob! Try that also and let me know how your adventures work out.
Ellison Hartley from Maryland, USA on February 24, 2019:
Can't wait to try it out and see if I can get some crows to hang out around our property.
Mike and Dorothy McKenney (author) from United States on February 24, 2019:
When I first started putting the eggs out, I cut them up but left them in the shell. The crows will eat them any way you serve them up but I worried about them dropping eggshells in our neighbor's yard so now I peel the eggs and cut them up. Thanks!
Mike and Dorothy McKenney (author) from United States on February 24, 2019:
They are pretty determined when it comes to the suet. Very entertaining. Thanks for reading and commenting!
Ellison Hartley from Maryland, USA on February 23, 2019:
I didn't know they liked hard boiled eggs!! I will have to tell my dad to start putting some out at his bird feeders!!! I think they are really cool birds. I wouldn't mind if we had some that lived on our farm property, we don't see them a whole lot.
Lorelei Cohen from Canada on February 23, 2019:
lol...yep I have my regular visitors to my suet as well.
Mike and Dorothy McKenney (author) from United States on February 23, 2019:
I love them as well, but at this very moment there is one sitting in the tree right outside my patio doors yelling his head off! I wish I knew what they were "saying" to each other.
Lorelei Cohen from Canada on February 23, 2019:
I am a big fan of crows they are one of my favorite birds although they can sometimes be too smart for their own good. Highly intelligent I love watching them.
Anything but Common: The Hidden Life of the American Crow
I imagine you have to use the gear that tree trimmers do to get to the tallest part of the tallest tree where the nest and babies are, and handle the babies and put tags and bands that are strange to them. Why does that not spook the parents and make them leave the nest? You always hear that birds and animals will abandon young ones if you scare them or make too much of a ruckus near their nests.>>
@Lee Ann van Leer Great question Kendra. Very interesting that so little is known about the courtship ritual. This is usually such a big part of what you read about whenever trying to learn about different birds from your standard guidebooks. Now I'm really curious why crows are so different (i.e., if it is in fact a short courtship period, then why? Does it make them vulnerable somehow?)
@Eveline Hello Eveline, Corvids in general don't show a lot of display for courtship. With the American Crows they typically form a long term pair bond so they aren't having to do a lot of courtship displays and rituals every year for breeding season like some other types of birds might do. Once the bond is formed it can last for many years or until one dies so the odds of a researcher observing that first time period that a new couple is pairing up for the first time is slim. That coupled with the difficulty in humans differentiating individual crows which can't be reliably told apart from another crow without them being tagged and or color-banded. If you are observing unmarked crows you don't necessarily know if you are observing a male or a female, parent, partner, child etc reliably. In the course there is an offer for course takers to get a discount on Birds of North America (BNA) subscriptions. BNA is our more in depth online encyclopedia of North American Birds. Here is an excerpt from Birds of North America, American Crow : Pair Bond Courtship Displays and Mate-Guarding. Courtship display, if it exists, is rare, judging by the paucity of reports on the subject (Good 1952). Allopreening, often actively solicited by either mate, occurs regularly, but largely ceases during incubation (Kilham 1989). Billing, seen infrequently, involves a mated pair gently fencing with their bill tips, and bill-grasping (Kilham 1989, CC). Members of a breeding pair stay in close contact during egg-laying stage (Caffrey 1992). Breeding male guards mate during time of sexual receptiveness. At start of egg-laying in Florida, males stood generally on 1 of 2 or 3 favorite perches, on the ground below the nest, on a fence post, or in a tree as far as 150 m away, watching for periods of 30 min. Males hardly fed their incubating mates during mate-guarding period helpers fed the females (Kilham 1989). In California and Oklahoma, guarding males sit for hours at a time, with only short breaks, in obvious high perches near incubating females (CC). Copulation Pre- And Postcopulatory Displays Based on Black 1941 , Kilham 1989 . During precopulatory display, both sexes crouch, bodies horizontal, wings out and drooping, and tails vibrating up and down females use same display posture during courtship begging (accompanied by nasal “ waahs ” CC). Sometimes this same display occurs in other context juveniles give it to older siblings and some-times to each other (CC). Begging nestlings and fledglings assume the same posture and produce nasal “ waahs ” as well (CC). Males sometimes pick up objects as part of copulatory behavior. During copulation, male settles on female, waving his outstretched wings female stands and vibrates her tail up and down while the male works his tail under hers. Loud, hoarse calls by female, audible 250 m away, heard during 13 of 30 copulations seen. Copulations occur on the ground, in trees, and on nests last from 4 to 12 s. Reverse mounting occurs (Kilham 1989 ).
American crows are protected internationally by the Migratory Bird Treaty Act of 1918. Despite attempts by humans in some areas to drive away or eliminate these birds, they remain widespread and very common. The number of individual American crows is estimated by BirdLife International to be around 31,000,000.
Summary: In literature, crows and ravens are a bad omen and are associated with witches. Most people believe they steal, eat other birds' eggs and reduce the populations of other birds.
Loud, Curious American Crows: Most People Either Love Them or Hate Them - pets
What should I do with it?
If in doubt, LEAVE IT ALONE.
Although I fully understand and sympathize with the desire to rescue baby wildlife, it probably is wisest to leave all wild animals alone. I am completely convinced that more young birds are unnecessarily ripped away from their parents and tortured/killed by well meaning people than are ever rescued. I believe that more young animals would survive if people would just leave them alone.
Ask yourself the following questions:
Why do you think it has fallen from the nest? Do you see a damaged nest? Birds almost never fall from their nests unless the structure has been damaged.
Is this a nestling or a fledgling? Do you know the difference? If not, read on and try to figure it out. A nestling could use the help a fledgling needs to be left alone.
Why do you think it is abandoned? Do you see a dead parent nearby? Most animal parents leave their young for long periods of time while they forage for food. Unless you know for a fact that the parents are dead, assume they are nearby watching worriedly.
Why do you think it is injured? Do you see blood or other signs of trauma? Not being able to fly or being uncoordinated is often misleading. (See below for more information.)
If an animal is in immediate harm's way, it should be moved into a safer area. By this I mean a bird in the middle of the street, or on the ground in the middle of a yard with a cat in it, or something similar. A bird on the ground can be put up in a bush or low tree that would keep it out of the reach of dogs or children. Ideally the cover location would have dense foliage that would conceal the bird and would be connected to more shrubs and trees that the bird could climb to.
One of the most frequent problems with "rescuing" wildlife is that the youngsters are doing fine and do not need help. Instead of being orphaned, they are being watched attentively by concerned parents, who often are making quite a ruckus while their babies are kidnapped.
Many people seem to expect birds to be able to fly on their own when they leave the nest. Most cannot, but rather leave the nest a week to 10 days before they can fly. People who see them assume that they have fallen from their nest. Here is the reality: birds just don't fall from their nests! The parents usually build nice sturdy nests. Only incredibly infrequently will the nest be disturbed enough that a nestling will fall out. In some species, however, and crows are one of these species, nestling birds may be THROWN out of the nest. That is, it is in the best interests of the parent birds to get rid of some of their own offspring, and they accomplish this by tossing a couple of kids. (Life is not pretty!) But, such things happen only relatively infrequently! (In these cases putting the young back in the nest will probably result in them getting tossed again. Either that, or that one will drag the rest of the nest into starvation with it.)
How can you tell the difference between a fledgling and a nestling?
For most songbirds, there is a good rule of thumb: the rule of the thumb! By that I mean, can the bird sit up on your thumb (or finger) on its own? If it can, then it is a FLEDGLING and should be left alone! Nestling songbirds cannot balance on their own or grip a perch until right at fledging. If the bird can balance ok, then it is SUPPOSED to be out of the nest. It may not look like it, but it is. It will have some feathers over much (but not all) of its body, and the wing and sometimes the head feathers will be sticking out of little tubes (the feather sheathes). It might still have tufts of down on its head or on other parts of the body.
So, if it seems ok, not injured, just unable to fly, and it can perch on its own, you should PUT IT BACK WHERE YOU FOUND IT. Even if the parents weren't right there yelling at you, chances are that they know where the baby was and were doing all they could to take care of it. Don't worry about them abandoning it because you touched it birds don't do that. (They might, however, abandon nests if you get too close, especially if they have eggs and not nestlings.) Just get it back to where they can find it and where it will be safe. Don't put it in an enclosed area that the parents will be afraid to go into. Get it somewhere it can eventually move off on its own.
But, if I don't pick it up my cat/dog will kill it.
Well then, keep your pet inside until the bird is gone. This helpless stage is temporary, and the bird will be gone in a couple of days. Is it too much to ask to keep your pets under control that long?
Why do birds come out of the nest so early if they can't fly for another week?
They come out for a good reason, namely that the nest is a very dangerous place to be. People tend to think of birds' nests as little homes that they return to each night, where it is cozy and warm. In fact for most birds, nests are a tragedy waiting to happen, and they leave them absolutely as quickly as possible. Think about it this way. Imagine that you are a small bird. You have lots of enemies that would like to eat you and your offspring (and eggs). What is your best course of action, go back to the same spot every night, or sleep hidden in different spots every night? What about your babies? Do you keep them together in one spot, or do you spread them out and move them around as soon as you can? Imagine that you have a nest hidden in a bush, and there is a raccoon that is looking for it. If that raccoon checks one bush every day, soon or later he is going to find your nest. Therefore, the sooner you can get those kids out of there, the better. Then you can spread them out and move them around to a different spot every night. Think about all those eggs and that one basket. It makes even more sense for birds to avoid that situation than people.
This is not just an abstract idea, either. During my dissertation work I studied the behavior of fledgling Florida Scrub-Jays, and I noticed that the first ten days out of the nest (they fledge on average at 18 days old) were by far the most dangerous. It seemed to me that the survival of the young might increase if they stayed in the nest until they could fly (at day 28). But, when I calculated the numbers, I found out differently. For reasons stated above in the raccoon example, a nest has a decreasing chance of survival as the nestling period progresses. I took the data on that risk for scrub-jay nests, and then compared it with data on fledgling survival. What I found was that if the jays stayed in their nests for another ten days they would actually gain ZERO advantage over coming out at the normal time. And after that time being outside the nest is significantly safer than staying in it. Yes, there are cats, raccoons, and hawks out there that would love to snatch up a nearly helpless baby bird, but if those baby birds can move around they will have a better chance than if they sit still.
Well, I'm sure it's injured, and therefore must need my help. What do I do now?
What makes you think it is injured? Is it bloody? Or is it just that it cannot fly? It is difficult to realize that baby crows are in fact babies. When a young crow leaves the nest it will be somewhere around 80 to 100% adult body weight, have legs that will never grow any further, and wings that are nearly full size. This is a large bird, to be sure, up to 300 to 450 g in weight. But they still cannot fly! I have had a number of fledgling crows picked up off the ground because the people thought they were injured. When I found them perfectly healthy and told the people that they couldn't fly because they were still just babies, the inevitable response was "But it's so BIG."
If it really is injured, if one wing looks substantially droopier than the other, if it has blood on its body, or it cannot grip with one foot, then find professional assistance . Do not try to fix it on your own. Call a veterinarian in your area, or get the bird to a licensed wildlife rehabilitator. Caring for wild animals is difficult, and requires specialized knowledge. If you do not know of a wildlife rehab person in your area, try looking for one at http://wildliferehab.virtualave.net. Call the closest person and see if they will take your bird, or knows someone who will.
Be aware that IT IS ILLEGAL TO POSSESS WILD ANIMALS, and that there are very good reasons for these laws. The main reason is to ensure that both the animal and the people remain safe.
Well, what's the harm in raising a baby bird? It will just go off and live its life and I'll have had the enjoyment of being close to a wild animal.
First of all, remember that IT IS ILLEGAL TO POSSESS WILD ANIMALS.
Close contact with wild animals can be a changing point in someone's life, making a nature lover out of an indifferent cynic. Unfortunately, it can change the animal's life too, and usually not for the better. In the case of crows several factors are involved. The biggest danger to a baby crow is ignorance on the part of the caregiver. Do you know how to care for a baby bird? How have you learned this information? It is NOT all common sense. If you think it is, you will probably either kill or torture the babies in your care without knowing it.
First of all, raising a baby bird is a LOT OF WORK! Baby birds need to be fed every 10-20 minutes or so, every day for their entire period of dependence. (Crows are dependent for about 2.5 months.) That's dawn to dusk, every day. You can't just leave them home with food in the cage until you get home from work. They can't feed themselves, but must have it pushed down their throats. At least twice an hour, every daylight hour, for several weeks. This is a big commitment! That is one of the reasons that rehabilitators hate to see healthy fledglings come in the door.
DIRECT EFFECTS ON THE BIRD
Diet and Nutrition. One of the most common problems is ignorance of proper diets. You are undoubtedly aware that not all birds eat the same things. Some, like cardinals eat primarily seeds, while others like warblers eat almost exclusively insects. So too are nestling diets somewhat specialized. Most baby songbirds are fed mostly insects and other animal foods, along with some plant foods. Some species, such as herons and seabirds have very specialized diets. Just as man cannot live by bread alone, so too do young birds have problems with simplified or inadequate diets. No bird can live on a diet of bread and milk! (Never feed dairy products to birds. Birds are all lactose intolerant (can't digest milk sugar), and if fed too much they will get diarrhea.) Nor, can they live on hamburger alone. If inadequate diets are given baby birds they may die, or grow up with health problems.
Stress (read "torture"). Do you know what the mental state of that animal is? Do you know when it is scared? Are you comforting it or stressing it? (Hint: no wild animal wants to be petted). This is one of the biggest arguments for why it is legal to shoot crows but illegal to keep them as pets. It is legal to give them a quick and clean death, but illegal to torture them to death.
Is that bird begging or yelling at you? Crows younger than 26 days old will beg at anything that moves. If you pick up a youngster before that age it will imprint on you and beg incessantly. Crows older than this age become wary and only beg at those things recognized as "parents." If you get a fledgling, it will gape at you and vocalize, but it is not hungry (necessarily), and it is not happy to see you. It actually it is frightened and is yelling at you to keep away. The good part of this is that you can still stuff food down its throat. The bad part is, of course, that you are stressing the bird. How do you tell the difference? Begging crows will try to get closer. They will stand up and stretch their necks toward you. Scared crows will lean away and might huddle against the wall of their box or cage. If a crow in a box has its head tucked between its wings or has its feet closest to you, it is scared. If it wants you to feed it, the face will be closest.
Future Survival. One common problem with hand raised crows is that if they are taken early enough they easily become imprinted on humans. This might seem like a good thing while you are raising it, but it is definitely a BAD thing. Crow babies make wonderful pets and are very appealing. Being very social they want to interact with you constantly (like a puppy, way more than a kitten). They are very curious and get into lots of funny situations. They are very personable, have very distinct personalities, and might even learn to say a few words (often only to one specific person). The downside of this behavior is that it makes them unafraid of people and very vulnerable in the wild. Over the course of my studies on crows I have spoken to a large number of people who have raised them as pets. All speak lovingly of the experience, but consistently, the stories end in one of two ways: 1) The crows start leaving for a day or so at a time (usually in the fall), and then are never seen again, or 2) some neighbor or someone nearby kills them when they are too friendly/aggressive. Usually this involves the crow trying to land on the head of an unsuspecting person or their children, which results in the crow being hit and killed with a stick or broom. I was astounded at the number of people whose stories ended this way. What I have almost never heard is the one I would expect the most, knowing normal crow behavior: that the crows left and kept coming back intermittently for a year or two. My wife had pet raccoons that did that, and I had a friend who raised a bobcat that did that, but I have spoken to only one or two people who have ever had a hand raised crow do that. I suspect that they don't get the chance because they got killed soon after they went out on their own.
I have marked only six crows that were raised by humans. One was killed by an owl (apparently as soon as it was released), a second was hit on the road and killed shortly after its release, a third was shot in the winter by a hunter in Pennsylvania (about 70 miles south of its release point), a fourth hung around its caretaker's for quite a while until it was presumed taken by a Cooper's Hawk, and the last two were never seen again after leaving their caretakers in the fall. No angry human kills yet, but one came very close it would have been killed if it had not been transported away to another site.
The sample size is small, but contrast the survival (or lack thereof) of these birds with that of my marked birds that were allowed to stay with their families. Of about 750 crows that I have marked late in the nestling stage over 10 years, over 50% of them were still alive the following spring. Of course the actual survival rate could be higher, as some of the ones I have not seen subsequently could have gone off somewhere else to live, or have eluded me in my follow-up searches (unfortunately, all too possible). Still, this is a remarkably high survival rate for passerine birds. Young crows still seem to get a lot of survival skills and knowledge from their parents and older brothers and sisters long after they are feeding themselves. I can't help but think that having an older family member around saying "Watch out for that!" or "Don't go down to that roadkill yet!" could have an important impact on a young crow's survival.
Social skills. Young crows may stay with their parents for a year or more, sometimes many years. While at home they forage together and stay near each other. Young crows learn a lot more than just what to eat and how to catch it. They also learn what is dangerous and what is not, and perhaps a number of skills that will allow them to prosper in crow society later on. In addition, they form family bonds that can last years and can influence the strategies that crows can use to find a breeding opportunity. (For example, a male crow might join a brother to help him raise young for a few years until another breeding spot becomes available.) Crows raised by people will have none of these advantages or opportunities for learning. It is possible that hand raised crows can join up with the large aggregations in the fall and learn how to be crows at that time. And then again, they might not. No studies have been published about the survival of captive raised crows, but it seems to me unlikely that they will be nearly as high as the high values I find for my wild crows. And because none of the hand raised marked crows I have followed have survived the first winter, I do not know if they would have had social problems too.
Well, I've got this bird that I can't return to its parents. Or, I'm a licensed wildlife rehabilitator, and how can I do the best for the crows in my care?
What is an adequate diet for a nestling/fledgling crow?
Crows are omnivores, and as such are somewhat easier to raise than some other species. The main thing is, growing youngsters need HIGH PROTEIN diets. Somewhere around 25 - 50% protein. Turkey starter is a good beginning to the diet. High protein dog food or puppy chow is also good and usually easier to obtain. (Both should be supplemented, though.) Look at the bags and get something as high protein as possible. Even then, it's only going to be around 27% protein. (Compare this amount with canned cat or dog food, and you'll see why they are not recommended.) You can supplement the protein content by adding protein powders or unflavored gelatin powder. Also as a part of the basic diet, add boiled eggs (especially important is the yolk) and include the shells (mashed up). Crows need a lot of calcium, so you might want to supplement with some other calcium source too. To 2 parts of the dog food you can add one part of cooked high protein baby cereal, then add one egg per every 2 cups of the formula. This is the basic mixture, and you can supplement it with things like mealworms or crickets, and raw beef kidney. As the birds get older and can feed themselves, offer them peanuts (unsalted), corn, sunflower seeds, fresh fruit, and mealworms or crickets. Do not feed too many mealworms! Mealworms are high in chitin, and can cause blockage problems if fed in too high frequency. (Mealworms alone are not an adequate diet for an insectivorous bird.) Once the crows are old enough to work food on their own (not until late summer or fall, probably), mice and day old chicks are favorite foods, if you can get them.
Someone gave me this healthy fledgling crow, but I don't know where it came from, so I can't return it to its family. Should I try to get the local crows to adopt it or should I just raise it myself?
Should you try to "give" this youngster to the local family? Maybe. We still have much to learn about individual recognition in animals. Although I am convinced that crows can recognize other individual crows, even if they have not seen them for months or years, I have no clue when or how they learn these skills. I have successfully reintroduced a kidnapped fledgling to its family after a two week absence. The family still had other dependent fledglings, and that probably was important. The initial meeting of the crows was a little rocky, with the youngster begging and being submissive while the attending adult investigated and then pecked the chick. After that, however, it was taken back in and fed again. This last year I also had a tagged young crow switch families. Two nests in adjoining territories were placed quite close together, and when the young of the two families fledged they apparently got even closer. One of the youngsters somehow went with the wrong family and was raised by it all summer. So, adoptions can happen.
Some female crows in my study have joined families that were not their own and did not have a breeding vacancy. They seemed to accomplish this feat by sheer persistence. They followed the family wherever it went, keeping a polite, but short distance. They were often chased by the family, but they persisted. After months of this persistence I saw no more aggression. Two crows eventually took over the breeding position when the breeding female died, and the other found a vacancy nearby the adopted family. It is possible that a young crow introduced into another family's territory could join that family through a similar pattern of persistence.
I encourage you to keep human contact with your young crow as limited as possible and to maximize its exposure to the local crows. The more it thinks it is a crow the better. If the family got to know this youngster from daily visits, once it was free-flying they might accept it. I would watch for the opportunity to get them together.
In any case, crows need other crows. If possible, keep several or all the crows you have together. Young crows should be released in groups if possible. Any captive wild crow will be unhappy if it is alone. I had a caged non-releasable adult female crow for a while, and all she did was pace back and forth and destroy the cocoa fiber mat in her cage. The moment I put in a second non-releasable crow (fortunately a male), she calmed down and showed no more neurotic behavior.
13 Surprisingly Weird Reasons Why Crows And Ravens Are The Best Birds, No Question
We're sure you have your favourite animal. It may even be a really smart one. But corvids - such as crows, magpies and ravens - really are something special. In fact, they're some of the most intelligent animals in the world.
And here we've gathered some of the finest examples of just how clever these gorgeous creatures can be.
1. Crows can reason out cause and effect
In a test on New Caledonian crows, crows were placed in an enclosure wherein a stick would emerge from a hide. They used two scenarios: in the first, a human was observed entering the hide before the stick moved, and leaving after. In the second, the human remained hidden.
In the first, the crows were much more relaxed after the human left, correctly linking the movement of the stick to the presence of the human. They would forage for food, and behave normally. In the second, the crow had no other reference for the stick's presence, so they remained wary.
"These results really seem to be showing that crows react in a very similar way to humans in a situation that requires them to reason about a hidden causal agent," says biologist Alex Taylor.
2. Crows understand water displacement
In an experiment with tubes published in PLOS One, scientists determined that New Caledonian crows can not only tell the difference between water and sand - they also understand water displacement.
The test involved tubes containing water and a treat floating on top out of reach. The crows filled the tubes with enough rocks or other heavy items to bring the food within reach.
They also were presented with different scenarios, such as tubes with different water levels. The crows showed an absolute preference for the tube that would get them the food with the least amount of work.
Their success rate was on a par with seven-year-old children, the researchers said.
3. Crows hold a grudge - and pass that grudge on to other crows
Ever wonder why crow researchers sometimes wear masks? It's because crows can recognise human faces, especially the faces of humans who have done them wrong.
So, if you're trying to record how crows react to negative stimuli (such as being caught and tagged), you don't want to do that using your real face. If you do, you'll get loudly scolded by the agitated flock every time you approach, as biologist John Marzluff discovered and detailed in a 2011 paper.
Good thing he did, too. A few years later, he found out that crows not only hold onto that grudge - they tell other crows about it, too.
Within the first two weeks after trapping, around 26 percent of crows scolded the human wearing the danger mask. Around 15 months later, that figure was 30.4 percent.
Three years after the initial trapping event, with no action towards the crows since, the number of scolding crows had grown to 66 percent.
4. Crows hold funerals for their dead
When a crow dies, other crows are often observed gathering around and making a lot of loud noise - much like humans, really. The reason for this was unknown until 2015, when crow researcher Kaeli Swift crowdfunded research to try and figure out why.
Her conclusion, published in the journal Animal Behaviour, was that crows gather around their dead fellows to learn about danger.
And it works. The city of Chatham, Ontario is beneath a crow migration route, and they plague the town on their way through. Every attempt to get rid of them has failed - including shooting at them with pellet guns. The crows learnt how to fly just high enough to evade the fire.
5. Ravens are smart enough to be paranoid
A study released in early 2016 found that ravens possess something known as the Theory of Mind - that is, the ability to recognise mental states within themselves, and extrapolate that others have mental states, too, and that those mental states in others may differ from their own.
Ravens like to stash food for later, and had been observed doing so more cautiously when other ravens were around.
To test this idea, ravens were trained to use a peephole to watch a human hiding food in an adjoining room. Then they were put in the second room with the food, and observed in two conditions: with the peephole closed, and with the peephole open and a loudspeaker playing raven cries.
They behaved just as if another raven was in line-of-sight.
This indicated, the researchers wrote in their paper, "that they can generalise from their own experience using the peephole as a pilferer and predict that audible competitors could potentially see their caches. Consequently, we argue that they represent 'seeing' in a way that cannot be reduced to the tracking of gaze cues."
6. Crows can solve complex, multi-step puzzles
This crazy impressive experiment was conducted as part of a BBC Two program called Inside the Animal Mind, putting crows to the test with the most complex animal puzzle ever.
And not lab crows, either. The crows were captured from the wild one at a time, and kept for just three months.
This one, nicknamed 007, is apparently a genius. The puzzle involved eight individual steps that had to be solved in a very specific order to release the food reward. He had to collect the tools, then use them to complete the next step of the puzzle. He was familiar with the individual tools, but had not had to combine their use before.
Seriously, watch the video. It's so good.
7. Crows can fashion tools
OK, crows can use tools. Great!
But what do they do if there's nothing available? Turns out they just make their own, the resourceful little poppets. In 2015, researchers announced they had filmed the first ever video evidence of crows fashioning tools in the wild using a specially developed spy camera mounted on the crows' tail feathers.
They were observed snapping twigs from trees, then stripping it of bark and leaves, and fashioned the node into a hook. They then used these tools to probe into small spaces for food.
"The behaviour is easy to miss – the first time I watched the footage, I didn't see anything particularly interesting. Only when I went through it again frame-by-frame, I discovered this fascinating behaviour. Not once, but twice!" researcher Jolyon Troscianko said.
"In one scene, a crow drops its tool, and then recovers it from the ground shortly afterwards, suggesting they value their tools and don't simply discard them after a single use."
8. Ravens use social ostracism to punish selfish peers
When someone in your friend group acts like an idiot, they may find themselves suddenly disinvited from social events, unfriended from Facebook, and their messages unanswered. Ravens don't have Facebook, but they do exercise similar ostracism towards conspecific dickheads.
In a 2015 study, researchers from the University of Vienna gave ravens a task wherein they would only receive the reward if they cooperated, pulling on ropes to raise a platform which had two pieces of cheese, one for each raven.
If one raven stole their companion's cheese, as well as their own, they were on the outs: the other raven would refuse to cooperate with them - but they would cooperate with other ravens who played fair.
"Such a sophisticated way of keeping your partner in check has previously only been shown in humans and chimpanzees, and is a complete novelty among birds," lead researcher Jorg Massen said.
9. Crows can exercise self control
Crows aren't driven purely by instinct - they can experience anticipation, and exercise self-control if the end result is a greater reward.
A 2014 study devised a test based on the Stanford marshmallow experiment, a 1960s study into delayed gratification in children. The first step was to determine which snacks the crows liked the most. The researchers fed them grapes, bread, sausage, fried fat and other treats.
Next, they were given a snack and the option to trade their snack - if they were willing to wait. They could either receive a better quality snack - meat in exchange for a grape, for instance - or a higher quantity of the same snack.
The birds preferred to wait until a better snack was on offer, but if it was just more of the same, they weren't. In some cases, they waited up to 10 minutes for a better snack. The fact that they waited for better quality, not quantity, showed that they were waiting because they wanted to - not because they were actually hungry.
10. Ravens can plan for the future and barter for items they need
When trained in the use of tools, ravens recognise the items as valuable and can set them aside against a future need. To figure this out, researchers trained ravens to release a treat by sticking a tool into a tube sticking out of a box.
Then they took the tool and box away, returning an hour later to offer the raven a choice of objects - one of which was the tool. After another 15 minutes following the raven's selection, the box was returned - 80 percent of the time, the raven had chosen the correct tool. The experiment was repeated with a 17-hour interval in returning the box, in which case the ravens had a 90 percent success rate.
For the next part, ravens had been trained to return a token to a human in exchange for a food reward. After an hour, they were offered three trays in succession with a choice of objects, one of which was the token and another of which was a low-quality snack, for a total of three tokens.
They chose the token on average around 73 percent of the time. After 15 minutes, the bartering experimenter would come back, and the raven exchanged the tokens for the prize.
"This study suggests that ravens make decisions for futures outside their current sensory contexts, and that they are domain-general planners on par with apes," the paper concluded.
11. Ravens remember people who have been nice to them
You know how crows hold a grudge? Well, corvids also remember people who have been nice to them. There was, of course, that adorable case of a little girl who crows started bringing shiny objects to after she regularly fed them - but there's been a scientific study on the subject too.
Again, it involves ravens trading a low-quality snack (bread) for a high-quality snack (cheese), which they'd been trained to do. Then two humans brought the cheese to trade for the bread. One experimenter would fairly give the cheese when the crow handed over the bread. The other experimenter ate the cheese themselves after being given the bread.
Then, after an interval - two days, and then later one month - three humans entered the enclosure, the fair one, the unfair one, and a neutral control. The raven was given a piece of bread to trade. Most of the ravens chose to trade with the fair experimenter - indicating that they remembered being cheated out of delicious cheese and weren't falling for that again.
12. Ravens use gestures to communicate
Before babies learn to speak, they communicate using gestures. Pointing at objects they want, for example. Outside of primates, this means of communication had never been observed in another species - until researchers observed wild ravens doing it.
They use their beaks like hands, Simone Pika from the Max Planck Institute for Ornithology and Thomas Bugnyar from the University of Vienna found.
They recorded 38 interactions between pairs of ravens, 25 of which involved the raven picking up an object and showing it to their companion, and 10 of which involved ravens offering an object to their companion.
"These distinct gestures were predominantly aimed at partners of the opposite sex and resulted in frequent orientation of recipients to the object and the signallers. Subsequently, the ravens interacted with each other, for example, by example billing or joint manipulation of the object," the researchers said.
13. Crows like to play
We're just going to leave you with this, because it's just so gosh-danged delightful.
Now go follow the Tower of London's Raven Master on Twitter. And don't say we never give you anything.