Crows Use Mirrors To Find Food

BBC Nature (Sept. 20, 2011) Clever New Caledonian crows can use mirrors to find food, according to scientists.

Researchers from the University of Auckland, New Zealand, tested wild-caught crows' reactions to mirrors.

The crows did not recognise themselves but found cached food items by studying their reflections.  The results put the birds in an elite group of species - which includes primates and elephants - known to be able to process mirror information.

New Caledonian crows (Corvus moneduloides) are known for their intelligent and innovative use of tools, such as twigs, which they use to fish nutritious insects out of holes and crevices.

Mirror experiments with other members of the same family of birds, the corvids, have found that magpies recognise their reflections but jungle crows do not.

In this study, published in the journal Animal Behaviour, psychologists examined the recognition skills of the notoriously clever New Caledonian crows.

Scientists captured 10 wild birds and placed them in large cages in order to record their behaviour in response to mirrors.

All the crows reacted to seeing their reflections as if they were encountering another crow; the birds made rapid head movements, raised their tails and even attacked the reflection.

Lead researcher Felipe S Medina Rodriguez said the crows' antagonistic reaction to their mirror image "was not surprising". He explained that an animal usually had extensive exposure to mirrors before it began to display an understanding that the image it was seeing was itself.

When the crows moved away from the mirror and lost sight of their reflection, they frequently searched behind the mirror to locate the "other" bird.

The researchers think that the behaviour was probably caused by the birds' lack of experience of mirrors; similar reactions have been recorded in primate infants and two-year-old children.

The second part of the experiment, though, revealed some surprising findings.

The scientists devised a task to test whether the crows could use mirrors to locate cubes of meat that were hidden from direct view.

All of the crows tested appeared to understand how the meat's reflection correlated to its location.

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The Private Life of... PIGS

AIRED: Thursday, 22 July, 20:00 on BBC Two

The Private Life of... turns its attention this week towards the mental lives of pigs.  Presented by Jimmy Doherty the series sets out to reveal the hidden lives of farmyard animals using a variety of simple psychometric testing measures.  Set on a farm in Dartmoor, Jimmy embarks on a quest to uncover the answers to questions such as, how sensitive is a pigs nose? Why can they find truffles underground? How do piglets find the right teat to feed from? (and by far the most interesting question of the episode), Can pigs recognise themselves in a mirror?

Traditionally the mirror test is a measure of self-awareness developed by Gordon Gallup Jr. (1970).  Inspired by the written accounts of Charles Darwin (1809-1882) and his reports on holding a mirror up to an orangutan and recording the corresponding facial and bodily actions.  Darwin suggested that these expressions were ambiguous and either signified that the primate was making expressions at what it perceived to the another animal, or it could be playing a sort of game with a new toy -  the animal might not be recognising itself but instead be attributing that image to another or, alternatively it might be recognising that the object that it holds represents an image of itself and so demonstrate an understanding of self-awareness.

It was through these observations that Gallup devised a test that attempted to gauge self-awareness by trying to discover whether an animal could recognise its own reflection in a mirror mark test.  Also referred to as the rouge test, the experiment is conducted covertly placing a mark of the participants body.  Ideally the spot should be placed in an area that is clearly visible to the animal in the mirror and can be physically reached with an appendage (reaching in this manner might suggest the identification of the foreign agent).  The control measure would therefore be a mark to an accessible part of the body but still remains out-of-sight.  Researchers then observe behaviours that might show the recognition of the placed mark.

To date animals that have passed the mirror test include all of the great apes, bottle-nosed dolphins, orcas, elephants and European magpies, with human children failing this test until they reach 18 months old.  Not surprisingly, pigs have previously been found to pass a variation of the mirror mark test, using the mirrors image to obtain information about a food source (Broom, Sena and Moynihan, 2009).  Under the watchful eye of Broom, it was precisely this measure of mirror self recognition that the programme used during the procedure.

Whilst the total amount of piglets used during testing was relatively low (expectantly due to the time constraints of the programme), the piglets did show a marked preference towards the location of the food when the mirror was present, suggesting that each piglet used the information from the mirror and its surroundings, deduced the relationship between the two and acted accordingly in finding the food source.  This therefore might suggest a form of assessment awareness in pigs.  Whilst the results were by no means conclusive, with a friend commenting on the suitability of the mirror mark test on an animal that has no flexible appendages and whether or not the piglet recognised itself in relation to the food (or just simple recognised the food), it does highlight the need for further research into the areas of animal cognition and self recognition.  I therefore suggest that what is needed are better designed measures of self-awareness and the acknowledgement of these mental lives in order to help in the welfare of all animal species.

Link: The Private Life of...Pigs