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Crows are undoubtedly the smartest of all birds. |
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First, find a special
twig with a curved end. Snap it off the branch and remove all bark and
leaves. Next, pare down the curve and fashion it into a sharp hook. You
are now equipped to go in search of large fleshy grubs, a tasty morsel
but one which likes to remain hidden from view. The quarry conceals itself
deep in leaf litter. However, it responds to repeated rustling in close
proximity by attacking the source of the disturbance. So you make vigorous
repeated probes with the wooden hook until dinner comes along. Contact!
Swiftly, you impale the wriggling grub and yank it clear of its leafy
lair. An impressive feat of hunting skill by human standards. Except that
the sleuth is not a person: all this ingenious detective work was done
by a crow in New Caledonia.
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Closer to home, every
member of the crow family provides insights that testify to avian intelligence
a cut above average. For
example, ravens can count - an ability lacking in other birds. Here's
the proof. Bird photographers filming nests from hides require an assistant
to accompany them into position. Both enter the hide together so that,
when the assistant emerges and wanders off, the bird assumes the coast
is clear and returns to its nest. Ravens are not so easily fooled. In
1937 Eric Hosking, a famous bird photographer, required the help of an
entire class of school-children to accompany him into a hide in order
to confound the mathematical skills of a pair of breeding ravens.
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Ravens hold another
record that could be unique for a bird: they have been recorded playing
in the wild. Their antics, photographed in Wales in 1980, involved two
birds taking it in turn to slide on their backs down a frozen snow bank.
The birds covered about 10ft each time and returned on a second day for
more fun and games. Normally ravens are encountered singly or in pairs
but 800 once came together to feed on the corpse of a dead whale in Shetland.
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Complex
social organisation is a hallmark of crow society in general and certain
species spend their entire lives living in groups. Rookeries, in some
cases centuries old, normally consist of about 50 birds but giant conurbations
of 16,000 nests have been recorded in Hungary and 9,000 in Germany. Highly
gregarious, rooks from several colonies merge to form communal winter
roosts. Even here, members of the same pair perch side by side and may
sleep together in a prospective nest. Group behaviour is exhibited throughout
the year and 'scouts' are deployed to warn of danger or to lead the way
to good feeding areas.
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Despite the impression
of massed, homogenous ranks, feeding gatherings can consist of family
groups or may be segregated according to age. Especially in late autumn
and early winter, juveniles regularly form flocks independent of adults.
By and large, life proceeds harmoniously. However, a code exists and antisocial
behaviour is sometimes punished by death at the hands of peers. So-called
rook 'parliaments' are occasionally convened and although the deeds of
the transgressor remain unclear the bird may be ostracised or, in some
cases, pecked to death.
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 Of
all crows, magpies exude a character that, on the one hand, is brash and
inquisitive and, on the other, seems sneaky and dastardly. They always
appear energetic and on the look-out for action. There is no doubting
their bravery since they delight in buzzing birds of prey and driving
them away. Yet, this action is puzzling. Magpies are not directly threatened
and arguably waste energy dive-bombing and harrying the raptor, sometimes
for long periods. Could it be that they are aggressive by nature and simply
spoiling for a fight? Elements of their social behaviour tend to support
this view.
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Within non-breeding
groups a dominance hierarchy exists. Males are normally dominant over
females. High-ranking birds initiate ceremonial gatherings by deliberately
flying into the centre of established territories to provoke a response
from the owners. The racket from the commotion sparks a reaction among
all the birds in an area and a gladiatorial contest over territory begins.
As many as 225 magpies have been counted watching the unfolding events.
The usual outcome may come as a surprise: in 95 per cent of cases the
troublemaker is evicted.
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In recent years magpies
have learned another lesson. They have discovered that it is safer to
live in cities and suburbia than in the countryside. Persecution is almost
non-existent in built-up areas, whereas farmers and country landowners
regard the species as a pest and treat it accordingly. Away from rural
areas, magpies are confident and less shy and, increasingly, seem to be
'born bold'.
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However, there is
a downside to their curiosity and undoubted intelligence. They are merciless
nest robbers. Even incubating adults may be attacked and killed. The species
sometimes hunts in groups and, outside the breeding season, has also been
recorded attacking birds at roosts. In one five year study in a suburban
part of northern Germany, 100 per cent of eggs and young of some species
in a 10 hectare area were taken, and 64 per cent of open nests were raided.
Gorgeous and brainy magpies may be, but their smartness would be even
more appealing if they weren't quite such a common sight.
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