Welcome back and Stamp Sunday

crow3 It's been awhile since we posted. Sorry! We haven't given up our love for crows, life just gets busy. We are back now and look forward to posting more regularly. We saw this beautiful crow by the waterfront. I wonder what he was thinking about...such intelligent birds. As it is a Sunday, we will throw in a corvid stamp -- and start a new tradition -- Stamp Sunday! Hope you enjoy!
Raven Stamp from Russia
Raven Stamp from Russia

Crows — An Australian Export?

Krahe Crow in Boots by Rudi Hurzlmeier
Krahe Crow in Boots by Rudi Hurzlmeier

I read an intriguing article about crows (and corvidae in general) and how they originated in an Australian part of Gondwana12, something I did not know. How very interesting! I learn something new every day! This article is worth reading but I won't re-post it here, I will link it instead. Just visit here to read the original article by Stephen Debus. Did you also know that Crows were most likely in the United States long before people?3 So, think of that next time you feel they are being pests and invading your land. Perhaps, the more likely story is you are invading theirs. It is a good idea to share and share alike with crows and humans alike. How much corn can they really eat? Plants a few extra stalk for them.
  1. In paleogeography, Gondwana (play /ɡɒndˈwɑːnə/), originally Gondwanaland, was the southernmost of two supercontinents (the other being Laurasia) that later became parts of the Pangaea supercontinent. It existed from approximately 510 to 180 million years ago (Mya). []
  2. Wikipedia []
  3. In the Company of Crows And Ravens By John M. Marzluff, Tony Angell, Paul R. Ehrlich []

Difference between Ravens and Crows

A fantastic video explaining (and showing) the difference between ravens and crows...   The people who made this video, Rick and Diana Boufford, have a fantastic website, Raven Diaries, with lots of goodies (information, stories, photos, a much longer video all about ravens...etc!) You should definitely check it out! And they have their own youtube account (Raven Diaries) here.

The Revered, Reviled Crow Clan by Howard Youth

I read an excellent article about corvids from their habitat to myths and legends about them in the May/June 2001 issue of Zoogoer. I think it is worth the read. Here is an excerpt: For centuries, a dark specter haunted the bloody battlefields of Europe. Waiting to feast on the dead, common ravens lined up at bloody clashes between invaders and invaded, tribes and kingdoms. War-weary observers could not ignore the jet-black scavengers, with their four-foot-wide wingspreads and cross-shaped flight profiles. Ravens, not surprisingly, were branded harbingers of bad luck, or death. Away from the carnage, common ravens (Corvus corax) also coasted into folklore, legend, and language, strongly hinting that these creatures and their 100-plus brethren in the family Corvidae are not your average birds. Two ravens, Hugin (Thought) and Munin (Memory), rode the broad shoulders of the Norse god Odin. In Inuit legend, the raven became creator and trickster. In the Bible, Noah sent not only a dove but also a raven to seek land, as did many ancient mariners. Tame ravens still stroll within the Tower of London's walls, where for centuries they've been sequestered as guardians against invasion. One reason why ravens, crows, jackdaws, rooks, magpies, treepies, choughs, nutcrackers, and jays stand out is that they have above-average brains—proportionately, they possess the largest cerebral hemispheres of the feathered set. Plucky, crafty, curious, social, vocal, and adaptable, corvids, as family members are known, are among our most familiar yet enigmatic neighbors. On all continents save Antarctica, they flourish in backyards and wilderness, although more than 20 species barely hang on within shrinking habitats. Ethiopia's thick-billed raven (Corvus crassirostris), bigger than a red-tailed hawk, is the world's largest songbird, while the dun-colored Hume's ground-jay (Pseudopodoces humilis) of the Tibetan plains is the smallest family member. In between lies a broad spectrum of glossy, splashy, and plume-tailed characters. You can read the rest of the article here.

Corvid cognition

Copyright © 2005 Elsevier Ltd All rights reserved. Nicola Clayton and Nathan Emery
aDepartment of Experimental Psychology and Sub-department of Animal Behaviour, University of Cambridge, Cambridge, UK
Available online 7 February 2005.

Article Outline

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.
Laboratory experiments confirm the sophisticated intellectual capabilities of these crows. One tool-using crow, called Betty, can manipulate novel man-made objects to solve a problem, such as reaching food in a bucket only accessible by using a hook to pull the bucket up. When the bent wire was stolen by another bird, Betty found a piece of straight wire that was lying on the floor, bent this wire into a hook and used it to lift up the bucket and reach the food! Betty proceeded to do this consistently. Furthermore, when given a tool box containing a variety of different tools to reach normally inaccessible food, she was able to select one of the correct length and width. So evidence of tool use and manufacture suggests that these crows can sometimes combine past experiences to produce novel solutions to problems.Feathered apes? Corvids are large-brained, social birds. They have an extensive developmental period in which they are dependent on their parents, and so have a long time-window in which to learn many different things from their parents and peers. They show a great propensity to find innovative solutions to novel problems, from the manufacture of tools to the protection of food from competitors. Furthermore, they appear to be particularly adept at predicting the future behaviour of conspecifics. These features are things they share in common with the apes. The common ancestor of mammals and birds lived over 280 million years ago, so it is hardly surprising that they have very different brains. It follows that intelligence in corvids and apes must have arisen independently in two groups with very different brains. Interestingly, the thinking part of the brain is correlated with propensity to innovate in both birds and primates, with the corvids and apes as the ‘star inventors’. So when it comes to intelligence, corvids are feathered apes.

Further reading

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


“Reprinted from Current Biology, Vol 15 / Issue No 3, Author(s) Nicola Clayton and Nathan Emery, Corvid cognition, Page No. 1, Copyright 8 February 2005, with permission from Elsevier.”
Direct Link to Article click here.

Are the words Ravenous and Raven related?

Simply, no. But... One could easily imagine the word ravenous, meaning 'voracious, very hungry', originating from the word raven. Particularly, if you have ever watched raven nestlings eat. They need to eat every couple of hours and not just snacks either. Bernd Heinrich in the Mind of the Raven gives us a snippet of exactly how much these young birds can consume. Here is a sample 4 day diet for (6) five-week old nestlings he was caring for: Day One: One woodchuck and one snowshoe hare (roadkills that [he] froze and then chopped up---skin, bones, guts, and all---into bite-sized chunks and thawed before feeding). Day Two: Three red squirrels, one chipmunk, six frogs, eight chicken eggs (crunched up shells and all). Day Three: Two gray squirrels, five frogs, six eggs, six mice. Day Four: One hindquarter of a Holstein calf. Picture this food in relation to these birds---raven fledglings---around half a foot long. THAT IS A LOT OF FOOD for their size. However, the correlation between the word ravenous and raven is simply happenstance. While ravens do happen to be very hungry, the word raven or 'ravin' is of Germanic descent appearing around 800 AD. The raven’s name comes from the Germanic root 'khraben' which is thought to have arisen as an imitation of the harsh, grating call of the raven itself.1 On the other hand the word ravenous is of Latin descent originally.2 This can be a bit confusing so let me try to keep the lifeline of this word simplified.
  • ‘Ravenous’ is derived from the Old French word ‘ravineux’ (original meaning: 'violent rush, robbery').
  • ‘Ravineux’ is derived from the Old French word ‘raviner’.
  • ‘Raviner’ is derived from the Latin word ‘rapinare’.
  • ‘Rapinare’ is derived from ‘rapina’ (original meaning: robbery, plunder, booty).
  • ‘Rapina’ is derived from the Classical Latin word ‘rapere’ (original meaning: drag off; snatch; destroy).
  • ‘Rapere’ is derived from the Proto-Indo-European root I ‘*rep-‘
The verb form of ravenous is “to raven”. It is quite proper to use the word in its verb form or in its present participle form ‘ravening’ which means “to search for or consume food voraciously.” Can any of you come up with some good uses of this word? If so, I will post them. =) So...no, ravenous and raven are not related etymologically speaking but we can still appreciate the correlation, can't we? While raven, in the bird sense, is as common as the bird---it seems the word ravenous in any of its forms is simply disappearing in everyday conversation. Tsk, tsk, tsk… We are fast losing so many wonderful words---forgotten---replaced with the ever-so-annoying text-speak.
  1. http://www.word-detective.com/021804.html []
  2. http://www.myetymology.com/english/ravenous.html []

Corvids play

Everything plays. Playing helps with motor and sensory skills as well as social behavior. It relieves stress. It teaches the young many important things needed for survival through the process of trial and error while they can still afford to make mistakes. It keeps relationships healthy. Social play helps children gain friends. Social play helps young lovers meet and flirt. Social play teaches us how to behave according to our social norms. It can give us solid practice on our role in society. Birds are no different than us. They play, although not all birds use social play. But young birds play more than fully grown birds. Bird play is often spontaneous and free-spirited. And corvids engage in all manners of play, including social play. It is easy to recognize a child playing. It can be just as easy to recognize a bird playing. For example, when corvids play they often soar together on air currents, swoop down only to rise again over and over. It resembles a flying game of tag. Corvids also use ordinary objects as toys. They will often drop twigs, stones, leaves, or even their food midair and then catch them before they fall completely. Much like juggling or tossing a ball into the air. "One Hooded Crow repeated this performance dozens of times, catching his 'toy' after it had dropped about 36 feet (11 meters)".1 He must have been one heck of a juggler. I can almost seem him as a human, throwing things up in the air and catching them in his mouth. The following antics, corvid play was described in the Handbook of Bird Biology by the Cornell Lab of Ornithology:
Ravens have been observed taking turns sliding on their tails, feet first, down a snow bank as well as repeatedly sliding down smooth pieces of wood in their cages. Ravens have been seen playing with dogs, taking turns chasing it around a tree. One captive raven was observed tossing a rubber ball, pebbles, or snail shells into the air and catching them repeatedly. This same bird would often lay on its back and shift various playthings (toys) between its beak and its claws much like many children do with their toys. Other birds fell forward from a perch like an acrobat, in order to hang upside down by their feet, wings outstretched, then let go one foot at a time. While upside down, they would carry pieces of food, or shift items from beak to feet. One, while holding onto a branch with his feet, learned to propel himself around and around the perch by flapping his wings, like a gymnast on uneven parallel bars in a sort of 'loop-the-loop. The same captive ravens also played balancing games: carefully walking out as far as possible to the end of a tiny branch until it bent downward, turning them upside down; or trying to stand on a stick or bone held in the feet, while balancing it on top of and parallel to a perch made from a thick, wooden dowel.
When given time and the resources birds will play. The corvids do. Perhaps it is the corvids extensive use of playing, allowing themselves and their young to learn and develop through playing that allows them to thrive when other bird populations are declining at an alarming rate. Sources referenced Podulka, Sandy, Ronald W. Rohrbaugh, Jr., and Rick Bonney, Editors. Handbook of Bird Biology. 2nd edition. Ithaca, NY: Cornell Lab of Ornithology, 2004.
  1. Podulka, Sandy, Ronald W. Rohrbaugh, Jr., and Rick Bonney, Editors. Handbook of Bird Biology. 2nd edition. Ithaca, NY: Cornell Lab of Ornithology, 2004. []