Tuesday, 16 June 2015

A congress of Corvids

A rook is a crow in a crowd

I am a jackdaw and barely get a mention

I am a Jay and he reveals all my secrets

I am a magpie and he keeps stum about my thieving
Rooks live and congregate together in large groups. Like  other corvids - crows, magpies, jays, jackdaws and ravens they are very intelligent birds. They have as much neurological nous as those other animal geniuses, the cetaceans and the great apes. Indeed their ability to use tools might be greater than that of a monkey and I imagine a corvid looks down on them in distain.
In telling their stories I will more or less group them together. In intelligence there are variations between species and although clever individuals will out think their relations they all provide an insight into theory of mind. Serious estimations compare corvid intelligence with that of a four year old child. Some sources say seven!

A murder of crows
It is sometimes suggested that their intelligence has developed from living together in complex communities. They have excellent facial recognition and indeed can recognise and remember we humans too. They will remember a disservice and bare a grudge - perhaps a man with a gun. They will  also remember and greet a friend, even bring him a present, after no contact in years.
It is said that crows can communicate their displeasure with an enemy. A murder of crows is a most apt expression.

Crow crosses
It might seem inconsistent with the theory that intelligence might evolve from a need to cohabit in large groups when solitary corvids are equally clever. I wonder how much hybridisation has contributed to the shared intelligence between these animal Einsteins. 

There are fascinating examples of crow hybridisation.

The carrion crow and the hooded crow are virtually genetically identical. In eight million DNA positions on their genomes variable code could equally apply to either species. Only in eighty three places is the code diagnostic for one bird or the other. Mind boggling when you consider that some of the differences between them are not insignificant. 

An American bird breeder advertises his hybrid ravens as a means to circumvent the US laws against domesticating native species. They apparently make wonderful loving and caring companions. 
(How on earth do you properly define a native species and why are American birds thought more worthy than our own?) 

Two years ago Cathi revived an expiring tiny sparrow that had been thrown out of his nest. Pimples is a happy little fellow that now flies freely in her home. No doubt he has outlived his thrusting brothers and sisters.

Stone the crows!
I frequently nearly crash my car when dumb pheasants  wander into the road. Not so with corvids. They steelily look you in the eye as they pick at some carrion and flit away at the very last moment. Even if you wanted to, you would fail to hit them. It is ironic and arrogant  that magpies and crows are classified as vermin and can be shot on a whim.

Eating crow
Crows have been observed watching the traffic lights turn to red to take a serving of ‘road kill’. As the lights turn back to green they hop away to await the next course.
Japanese corvids exploit the traffic in a different way when cars shell their nuts that they drop in the road.

As the crow flies
They seem to have got cars ‘sorted’. An American professor has befriended the corvids that he studies. They recognise his car as he drives to the research site and fly in parallel with the driving seat as if they belonged to Air Force One! 
Cathi tells me that a crow used to follow Harry’s bike to school every day. I can just imagine it slip streaming the back of his ears. The crow would fly home and pick his mother’s pegs off the line.

I can’t imagine Harry on a bike
Although trivial, personal stories are best. Cathi remembers as a child in Africa when a corvid regularly mimicked her baby sister crying and her mother would come running. What was really clever was that the crow was not merely mimicking but was having fun as it cawed away at her mother’s ire.

Mother crow

I am a juvenile crow and follow the Green Crow Code
I was recently enchanted by a letter in the New Scientist from Rod Cripps. I quote
“We have a local family of Australian Magpies. One morning a chick ran out into the road. Mother magpie immediately rushed out and grabbed the youngster by the neck feathers, dragged it back to the side of the road and vocally severely chastised her!”
What a fascinating story which encapsulates several corvid characteristics. Like humans they have a very long childhood because they have so much to learn. They clearly are able to communicate such information. In addition they do not just rote learn but can solve problems too.

Crow feats
In an Aesop fable a crow raises the water level in a pitcher to drink by dropping stones in the water. This has been experimentally verified when water levels have been similarly raised up in a beaker. When no stones were provided the crow flew off and brought back his own.
On another occasion a floating tasty caterpillar morsel was similarly elevated.  Apparently when offered potentially floating ballast the crows have the wit to refuse it.

I am only a simple sparrow and can’t read the instructions
I just use my head
It is well known that  some corvids fashion twigs to extract insects from nooks and crannies. They have learned from their parents the relevant pruning. Apparently designs vary with the birds geographical distribution  - a sign of learned behaviour and a high level of thinking they share with the great apes. One clever crow fashioned a suitable hooked tool by twisting wire.

Cashing the cache at the crow bar
Jays have prodigious memories with regard to storing their food. They remember hundreds of sites and when to return before different foods ‘go off’ in the larder. They have well honed skills of deception when they know potential thieves are watching. Sometimes they will go back later to recache elsewhere. Jays that themselves have thieved are the most cunning cachers.

Sense of fun - crowing over the dogs
They have a rather cruel humour. A blog correspondent related the story of his daft dogs in his walled garden. The crows would goad the dogs and taunt them to chase. They would fly close to the ground and at the last minute would swoop vertically. The dazed dogs hit the wall. This was repeated ad nauseum and the dogs never learned!


He is called ‘Floppy Wing’ and was rescued, apparently shot, almost comatose and unable to fly. Cathi fed it her life giving glucose based elixir and it was nourished in her field with the hens unable to fly for several weeks. Eventually with a huge effort it launched itself in the air and ascended a small garden tree. After several months it made its way down the hedgerow to rejoin its friends in the rookery. Corvids aid injured relatives and acknowledge and perhaps mourn dead ones. For many years Floppy regularly appeared in our gardens still mainly walking.

Floppy and friend
Scare crow
I looked out of our conservatory and there were a thousand crows feeding on grubs in the farm field. I stealthily sneaked out ever so quietly with my camera. No joy their lookouts immediately spotted me and immediately flew away. I did not want it, but it was such a feeling of power that all these intelligent birds thought me a threat.

He’s been shooting a line
Pimplette


10 comments:

  1. Nice story, beautiful pictures. We have some Jackdaw friends in our garden. They have a nest in our dovecote two metres from the verandah for the third year. The young ones are almost flying out now, they are doing flying exercises in the dovecote and look outside sometimes. Two years ago I made a blogpost about them.

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    1. You are welcome to put a link on if you want Janneke

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  2. We have magpies bringing hard bread from elsewhere and softening it in the bird bath and they have tried the same trick with chicken bones.

    Don't crows also have creches for youngsters?

    Ignore a jackdaw see my post tomorrow

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    1. link it if you want Sue
      I expect they do have creches. You gave me a moment of panic when I thought I might have used the term creche and not cache - and spoilt all my puns!

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    2. It's only a coup[le of photos,

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  3. Apparently in times gone by (hundreds of years ago, I expect) Crows used to be popular as household pets - more popular than cats! I can't imagine anyone wanting to keep them as pets unless they had a very large house.

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    1. That sounds a really interesting example of social history. I'd love to know more about it.

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  4. I really enjoyed all the stories about the crows and sparrow, especially saving them. Your photos are wonderful too. I never heard of hybrid ravens in the US for sale, interesting. I have a cockatoo and he has a crow friend that visits him at his window each summer. They yell at each other so I am not sure if they are actually friends.

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    1. I would love to see them! We have a love bird who is very intelligent and flies free in the house but who totally ignores birds through the window. He thinks he is human! If he hears recorded birdsong however he squawks with delight.

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  5. Cathi has been talking to Harry’s mother about the crow that followed him to school every day. Apparently the bird picked the pegs off the NEIGHBOUR’S line!
    The crow was apparently semi domesticated.
    Harry’s mum is an Austrian lady and sixty years ago she seemed German and was subject to some local prejudice. The crow also went down the neighbour’s row of vegetables as well and pulled everyone out!
    Perhaps we anthromorphise too much?

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