The Predator (2018)
I did a previous post on this rare bird but I have found new information, so let’s read about it again, shall we?
According to the IUCN 3.1 Red List, the Andaman Treepie is nearly threatened. It is endemic to the Andaman Islands in India. Since the Andaman Treepie lives within a very limited habitat, it is in danger of extinction due to habitat loss. The IUCN explained further,
Dendrocitta bayleyi is endemic to the Andaman archipelago, India, where it is usually found in pairs or parties of up to 20 birds, or in mixed flocks in tall trees in dense broadleaved evergreen forest. It is uncommon to locally fairly common and while habitat on the Andamans remains relatively intact it is probably secure. However, indications that an increase in human populations and habitat loss is occurring in the archipelago suggest that within the small range of this species natural habitats might rapidly shrink and become fragmented.
It is unfortunate that one of the corvidae family is nearing extinction due to loss of habitat. Can there be no uninhabited places on this Earth? Can we not leave room for the other species?
(BirdLife International 2008. Dendrocitta bayleyi. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.2. . Downloaded on 02 August 2010.)
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.
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
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
Another excellent photograph found on flickr. This one is by Mark Cummins. If you click on the photograph it will take you to the URL where it is originally posted.
I am not 100% certain what particular bird this is in the corvidae family. However, I think it might be a rook but I am reluctant to say this for certain with authority because I am not so familiar with rooks to recognize off the top of my head. It looks like a rook and it looks like it the same bird I previously posted by the same photographer and it was a rook. So, I imagine it is either the same bird or a similar one. =)
This is the Corvus frugilegus which means “food-gathering” in Latin. They are more commonly referred to as the Rook. I have not had the great pleasure of seeing this bird in person but I am very excited to learn about it. It looks like a harsher, thinner crow. It appears, to me, to have had a hard-knock-life. I like how it wears its character, much like I relish the quirks in people; a wrinkle earned through years of laughter and tears, an innocent freckle just above the wrist, the shy happiness in a crooked smile, the confident swing of a left-leaning gait.
From what I’ve learned about the Rook, you can differentiate it from similar corvids by looking for the “bare gray-white skin around the base of the adult’s bill in front of the eyes or the feathering around the legs; it looks shaggier and laxer than the congeneric Carrion Crow.”1
It seems it is found all over Europe and east of Europe. I read that it is found in Great Britain quite frequently.
Much like all corvids, it is a survivor. It will eat just about anything depending on where it lives. It prefers earthworms and insect larvae but will eat cereal grain, fruit, insects, crustaceans, small animals, acorns, bird eggs, and will pilfer through the trash for food scraps in urban areas.2
The Rook nests together in a colony. This is commonly referred to as colonial nesting which means nesting with many other birds in a safe place and living commune-style. The Rooks learn from one another and find food together. They protect one another but they are still predatory birds, so they can be found stealing from another from time to time. They prefer to nest way up high in trees. They typically have 3-5 eggs which are incubated for 16-18 days and the fledglings are cared for by their parents and other rooks for about a month.
Once fully fledged, they get together with other single rooks and sometimes even jackdaws and fly around, presumably deciding who they will mate with in the future. Or perhaps just enjoying the free, young, single life…flying around without a care.
You can hear a rook here.
It sounds much like most crows but maybe a little throatier which matches how they look, for me anyways. =) I like their throaty “caw”.
Rooks are interesting birds. And so they are written about…people speculate about their abilities and even conjure up powers for these intelligent birds. I found the following on Wikipedia… it is a direct copy and paste but interesting.
Like many other members of the Corvidae family, the Rook features prominently in folklore. Traditionally, Rooks are said to be able to forecast weather and to sense the approach of death. If a rookery — the colonial nesting area of rooks — were abandoned, it was said to bring bad fortune for the family that owned the land. Another folk-tale holds that rooks are responsible for escorting the souls of the virtuous dead to heaven. William Butler Yeats may be making reference to the latter tale in his poem The Cold Heaven.
In Neil Gaiman’s Sandman comic book series, Abel reveals that the parliament would surround a single rook, with that one telling a story. If the story was not liked, the parliament would attack and kill the speaker.
In Brian Jacques’s Redwall series, rooks make an appearance in Mattimeo. Rooks, along with magpies and other similar birds make up the army of General Ironbeak, one of the villains in the book.
In Susan Cooper’s The Dark Is Rising series, rooks are seen as agents of the Dark and the sign-seeker, Will Stanton is warned never to fully trust one.
In Phillip Pullman’s book Northern Lights Lyra Belacqua and Roger Parslow catch and heal an injured rook on the college rooftop.
In Stephen King’s Dark Tower entry Wizard and Glass, one of the characters, Cuthbert Allgood, carries a rook’s skull tied around his neck, claiming it as a good luck charm.
I am now an official fan of the Rook. I may always have been but I simply did not know it.
Do YOU have a Rook story to share with me? I would love to hear one (or many!) If so, e-mail me below.