THROUGH our still dark spring evenings, murders have become more prominent in our city. Suburbanites on their way home from work in the sunset evenings can hear those unnerving cries from the remoter wooded areas of the city's public parks.
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| On these dark evenings you can hear the cries of murders.... |
Early sunset is the signal for huge collective swirls of crows (known as murders) to circle noisily before roosting for the night.
Back in the early winter months they would fill up at farmer’s grain fields and at allotment complexes like ours. Back home in the garden where I had a score of cabbages under bird netting and within reach of our cat, the tell tale signs are still there that crows have still managed to have a go at them and strip hefty lumps from the close guarded heads.
Now that spring has sprung they'll soon be driving allotment owners crazy by picking out pea sprouts
to feast on them. I recall the year before last when one grower on our
allotment complex lost a huge pea bed and showed me a single lone pea shoot
remaining. He swore that the crows had left it there “just to torment me.”
Science is showing that crows do indeed play jokes – on each other at least.
Corvids have been a long time pet subject for the US
technologist and author Joshua Klein who has devoted more than ten years
studying the behaviour of crows and has also presented a much lauded TED talk entitled "The Amazing
Intelligence of Crows."
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| Josh the crow man - see his thought provoking TED presentation at http://www.ted.com/talks/joshua_klein_on_the_intelligence_of_crows.html |
Science has only
recently realised that corvids, the bird family which includes crows, ravens,
jackdaws, magpies and jays, are at least of equal intelligence to apes and
dolphins. In experiments crows in particular have been observed bending lengths
of wire into hooked tools. They have also been observed using three different
tools in sequence to solve a problem, the only animals on earth to do this
without training - apart from humans. This means using a short tool to hook a
medium length tool that is out of reach, using this in turn to hook a longer
tool similarly out of reach and finally, using this to hook food which can only
be reached by the longest tool.
In Japan
they have been observed dropping nuts among traffic at pedestrian crossings.
The cars crack the nuts and the crows wait until the lights have stopped the
traffic before strutting out to eat them safely, returning to the curb when the
sequence starts to change again. More recently I was told by a fisherman friend
how he and his fellow anglers were forced one day to row their boats in double quick time when crows started
picking out fresh water oysters exposed by a drought and
dropping them on the roofs of the fisherman’s cars from a height to crack them
open.
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| Crows - swotting up on the habits of humans. |
Crows have long had a reputation that causes food growers to persecute them as vermin. Gun clubs up and down the country reward their
members with bounties payable on the heads of grey crows and magpies. Points
are awarded which are later redeemable against cartridges. And despite experts claiming that crows
rarely attack lambs but rather prey on the corpses of those who die young, it
is still accepted that they are killers. Hanging crow carcasses upside down is
common practice on farms holding sheep as well as food crops.
For his part
though Klein decided it’s time to stop persecuting such intelligent animals and
to think of ways for your local murder to do something constructive. So he
hired them.
Klein
invented a crow “vending” machine which dispensed one peanut every time a coin
was dropped into it. He conditioned his local crows by covering the machine in
coins and when a crow inadvertently knocked a coin down the chute, a peanut was dispensed. Soon the crows were
busy shoving coins down the chute to get peanuts. Before long the coins on the
machine had been used up, but Klein had placed more coins around it. While the
placed coins around the machine were soon used up, the crows realised that once they had found a
coin, they could take it back to the vending machine, insert it in the slot and
earn a peanut.
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| Josh Klein's Crow vending machine - earning him cash in the recession . |
Klein has
yet to tell us how much he has earned by hiring crows rather than persecute
them but he stresses that his crow vending machine was designed to prove his
point that it was indeed possible to train a wild an intelligent species like
crows to do constructive things in exchange for reward. He has proposed ideas to thus condition crows
to pick up rubbish after stadium events or to pick out expensive components
from discarded electronics. He’s even suggested search and rescue functions.
While crows
have long been considered the food grower’s nemesis and a general pest, we food growers sometimes lose
sight of the fact that they also serve vital functions in the environment and help us in many ways.
First they are garbage removers by eating carcasses of deceased animals, second
they are ceaseless predators of other pests that eat our crops notably mice, slugs, snails, caterpillars, grubs and
moths. Maybe we should give them a break.
At least some leniency might finally stop them wrecking our cars and otherwise playing tricks on idiot humans!
