What a fun video! This raven is intelligent and figures things out quickly… check it out…
Scientists believe the fable of the crow and the pitcher might have been fairly accurate given the new research showing rooks using rocks to raise the level of water where a worm resided… to bring the worm up to their level.1
They are such incredibly intelligent birds. The other animal who showed fluid mechanics was the orangutan. I will bet corvids are just as smart if not smarter than many of the primates.
You can read more about the studies here.
- http://www.telegraph.co.uk/earth/wildlife/5983953/Aesops-fable-is-true-shows-crow-study.html [↩]
We know many people do not share our appreciation for crows and jays. They can often been seen as pests or bullies, particulary when it comes to backyard bird feeders. If you want to keep the crows and Jays away from your bird feeders, protecting your little birdies, you can throw out whole pieces of bread (away from the feeders), cereal flakes or corn chips. These big pieces of food are edible for all birds but intimidate most of the smaller birds. The smaller birds prefer the seeds and smaller nuts. While the crows and jays can hardly resist the bigger food sources thrown towards them. This will ensure that all the birds are fed and safer.
Another way to entice the bigger birds with the bread is to spread suet on it — they will be unable to resist this open-faced energy sandwich.
Be sure not to throw out moldy bread. This can harm the birds and we DO NOT advocate harming any birds—particularly our beloved corvids. We also do not recommend putting bread out while it is raining because birds don’t like soggy bread anymore than we do. The big birds and small birds can peacefully coexist in your yard or porch, if you just take a few extra steps. =)
Copyright © 2007 Elsevier Ltd All rights reserved.
The social life of corvids
Available online 20 August 2007.
Of the 120 species of birds in the corvid family, which includes the crows, ravens, magpies and jays, the bare-faced rook is perhaps the most social of them all. At a rookery in Norfolk, for example, winter roosts can number up to 60,000 individuals. The name for a congregation of rooks is a ‘parliament’. In English folklore, parliament is an apt name for rook justice, as it is said that rooks form a circle around a wrongdoer producing a cacophony of calls and caws which can go on for hours until the offender is either attacked and killed or released to live another day. Although only fiction, such tales reflect their canny reputation as thieves and tricksters, as well as possessors of great wisdom.
Like most birds, corvids are monogamous, and the core unit is therefore the mated pair. This pair bond is typically for life, and the pair remains together throughout the year. For example, rooks and ravens find a partner during the autumn months, taking part in impressive aerobatic displays and food sharing which may be to assess the quality of a potential mate. Once juvenile rooks and ravens pair, they engage in extensive mutual preening and bill twining (bill holding) and support one another in fights.
Copyright © 2005 Elsevier Ltd All rights reserved.
Nicola Clayton and Nathan Emery
What is a corvid? There are just over 120 species of corvids, a family of songbirds that includes the crows, ravens, rooks and jackdaws, as well as the more colourful jays, magpies and nutcrackers. Although belonging to the same order as nightingales and other birds with melodious songs (Oscines), corvids tend to be identified by their raucous calls. Little is known about corvid songs, perhaps because they are surprisingly quiet. Corvids can be found throughout the globe, except for the southern most tip of South America and the polar ice caps. In Britain, many of the common species, such as magpies and crows, steal other birds’ eggs and raid agricultural crops. They are therefore treated with disdain by many birdwatchers and farmers.
Why study intelligence in crows? Corvids have not always had such a bad press. Native Americans believed that a raven had created the earth; the Norse god, Odin, consulted two ravens Hugin (Thought) and Munin (Memory) for their wisdom; and Aesop cast corvids as the smart protagonists in many of his fables. Along with their reputation in folklore as the wisest of animals, corvids have the largest brains for their body size of any bird. Perhaps most surprisingly, the crow brain is the same relative size as the chimpanzee brain. Other aspects of corvid biology also give us clues to their intelligence. In the wild, young corvids have an extensive developmental period before they become independent from their parents. This allows them more opportunities to learn the essential skills for later life. Many corvids also live in complex social groups. For example, in the cooperatively breeding Florida scrub-jay, several closely related family members share the responsibility of raising the young with the parents. Furthermore, rooks congregate in large colonies, where juveniles associate with many non-relatives as well as kin. In both cases, this long developmental period provides increased opportunities for learning from many different group members.
Perhaps it is not surprising then that many corvids are also renowned for their innovative feeding skills. For example, Japanese crows in Sendai City have learned to crack nuts safely by dropping them onto pedestrian crossings and waiting until the traffic lights turn red before retrieving the nut’s contents. Rooks at a motorway service station in England have discovered a novel method for gaining access to food thrown in rubbish bins. Two birds cooperate in pulling up the bin liner and then either feeding from the raised food or tossing the contents onto the ground where the waiting crowd of colony mates reap the rewards.
As the crow flies… Most of the corvids that have been studied in detail hide food for the future in times of food abundance and then rely on memory to recover the food caches at a later date when food is scarce. For example, the Clark’s nutcracker is estimated to hide over 30,000 pinyon seeds in many different places during the autumn in preparation for the harsh months ahead. Laboratory experiments have shown that they have highly accurate spatial memories, which enable them to recover these caches up to 9 months later. This is no mean feat when there are so many caches to keep track of, scattered throughout the territory, and when many aspects of the landscape change so dramatically across seasons. It has been suggested that Clark’s nutcrackers rely on remembering the location of large vertical landmarks such as trees and rocks in the environment, because these landmarks are unlikely to be blown away or buried under the snow.
What do scrub-jays recall about past caching events? Although western scrub-jays do not hide as many seed caches as the nutcrackers, they are known to cache a variety of perishable foods, such as insects and fruit, as well as non-perishable nuts and seeds. In the laboratory, these birds demonstrate remarkable memories for what they have cached on a given day, and how long ago, as well as where they hid the various food items during that particular caching episode. This ability to remember the ‘what, where and when’ of specific past events is thought to be akin to human episodic memory, because it involves recalling a particular episode that has happened in the past. Until recently, this ability was thought to be unique to humans.
Avian espionage… Food-caching is a risky strategy, however, because the caches can be stolen by other birds. In addition to hiding their own food caches, corvids also play the role of thief: they watch and remember where other birds have hidden their caches and use this information to steal those caches when the owner has left the scene. When playing the role of thief, speed is of the essence and may make the difference between a successful raid and vicious attack by the owner of the food-cache. Not surprisingly, corvids also employ a number of counter strategies to reduce the risk that their own caches will be stolen by another bird. For example, they attempt to cache out of sight from potential thieves, or wait until the raider is distracted before hiding their caches, and if that is not possible, they hide caches in places that are difficult for the thief to see. When there is little option but to cache when others are around, then the birds will return to the caches once the others have left, and quickly re-hide any remaining caches in new places unbeknown to the potential raider.
Laboratory experiments have established that western scrub-jays use all these techniques to protect their caches from potential thieves, and only do so if another bird is present at the time of caching. Furthermore, they only move their caches to new hiding places if they have been thieves themselves in the past. Naı̈ve jays, even ones who have watched other birds caching but have never had the opportunity to raid those caches, do not do so. This suggests that experienced birds relate information about their previous experience of being a thief to the possibility of future theft by another bird, and adjust their caching behaviour accordingly. Using your own experience to predict another individual’s future behaviour in relation to your own – ‘putting yourself in someone else’s shoes’ – is thought to be one of the hallmarks of Theory of Mind, another ability that was thought to be uniquely human.
Cultural tool use in crows? New Caledonian crows are extraordinarily skilled at making and using tools. In the wild, they make two types of tool. The hooked tools consist of twigs that are trimmed and sculpted into a functional hook, which the crows use to poke insect larvae out of tree holes. The crows also manufacture stepped-cut Pandanus leaves, which they use in different ways for different jobs: they make rapid back and forth movements for prey under soil, yet slow deliberate movements if the prey is in a hole. These tools are consistently made to a standardized pattern and carried around on foraging expeditions. The only other animals that display this diversity and flexibility in tool use and manufacture are the great apes. Thus, chimpanzees have been observed to manufacture a range of different tools that are used for specific purposes, and different geographical populations of chimpanzees use different tools for different uses, suggesting that there may be cultural variations in tool use. Observations of the crows’ tool use in the wild also suggest similar levels of cultural complexity. For example, there is potential cumulative evolution in the complexity of stepped tools (increasing the number of steps required to make a more complex tool), analogous to minor technological innovations in humans. Crows from different geographical areas have different designs of tool, suggesting that crows may also show cultural variations in tool use.
Where can I find out more?
R.P. Balda, A.C. Kamil and P.A. Bednekoff, Predicting cognitive capacities from natural histories: examples from four corvid species, Curr. Ornithol. 13 (1996), pp. 33–66.
N.S. Clayton, T.J. Bussey and A. Dickinson, Can animals recall the past and plan for the future?, Nat. Rev. Neurosci. 4 (2003), pp. 685–691.
N.J. Emery and N.S. Clayton, The mentality of crows: Convergent evolution of intelligence in corvids and apes, Science 306 (2004), pp. 1903–1907.
Heinrich, B. (1999). The Mind of the Raven (Harper Collins).
G.R. Hunt and R.D. Gray, Diversification and cumulative evolution in New Caledonian crow tool manufacture, Proc. Roy. Soc. Lond. B. 270 (2003), pp. 867–874.
L. Lefebvre, S.M. Reader and D. Sol, Brains, innovations and evolution in birds and primates, Brain Behav. Evol. 63 (2004), pp. 233–246.
A.A.S. Weir, J. Chappell and A. Kacelnik, Shaping of hooks in New Caledonian crows, Science 297 (2002), p. 981
We often spend Sunday watching birds. This Sunday our crows were allowing us the rare opportunity of taking their photographs with a little help of a zoom lens. They were chasing the ducks and squirrels off the lawn—away from the peanuts we threw down there. They were not successful as you can see in the extra photographs we included. Here are the photographs we got—for you to enjoy them with us.
The crows are so suspicious. They do not want you to be near when they are eating. I wonder if this is due to years of humans eating crows or because people in general are not nice to them or are they just super private birds? They won’t eat with me present. They could just wait until I walk into another room and swoop in to grab some peanuts. They could wait until I close my blinds. They generally do. They circle around like vultures waiting for me to get lost so they can eat in peace. I decided to stick around my porch today — to try to watch them, see if I could take their picture. They did not like that idea much at all. They were cawwing and bouncing on the peak of the adjacent rooftop sqwaking their protest at my presence. It was rather humorous. They really wanted rid of me. So, I obliged. And a few minutes later…they swooped in to gather the peanuts. I caught some at a distance through the blinds, through the glass door and through my porch. Here they are…
We feed our crows peanuts daily. With the issues around salmonella and peanuts — I have been a bit nervous about giving them to the crows. I bought some peanuts I thought were safe AFTER the recalled products left the shelf but upon inspecting these peanuts — I am not so certain.
Did you know that the corvid-family of birds cache food for later — saving it in multiple spots for many months? They also watch other birds cache food and steal it–moving it for themselves. They are sneaky. They pay attention. This is interesting. There brain size to body ratio is relative to primates. They are social. We really enjoy watching them interact, eat and check things out.
Their ability to remember for long periods of time is fascinating. Some corvids have been observed recovering food caches up to 250 days after hiding them. Studies suggest this is due to their ability to use spatial memory ability. What is located next to what — such as many children do.1 “By the McDonalds over by my school mommy.” This is simply astonishing to me that corvids have such an excellent memory.
Maybe their abilities to cache food and to forward-think help them to survive when other birds are not doing so well.2
We put out peanuts without shells today for the first time. They were a hit. The crows like not having to open the shells and they attracted two more kinds of birds as well. =) Fun!
The crows seemed to be done for the day. The bowl was still about 1/4 full but they flew off. However, when a stellar jay showed up and started eating some of the peanuts, they came back cawing and trying to scare him off. He flew away but then when they flew off, he flew back. It was rather comical to watch. =) I think the new peanuts attracted him.