Page 17 - BBC Wildlife Volume 36 #10
P. 17
WILD OCTOBER
Hidden
N
f you are one of the
75,000 Brits who feed
the birds in your garden,
I and you’re blessed with a One for later: coal
tits often flit of with
little curiosity, you might have
nuts from garden
noticed that your avian visitors feeders to stash in
don’t just pitch in and eat – they NICK tree-bark crevices.
behave strategically. To them, BAKER
the feeder represents a patch
resource: a weird metal tree Reveals a fascinating
bearing strange fruit hanging in world of wildlife that
Perspex tubes and wire cages. we oten overlook.
To them, it’s an ephemeral
source of food, and they act Making continuous repeat This strategy creates one
accordingly to exploit it to the COAL TIT visits allows them to dodge the obvious challenge for the
maximum. Watch carefully and competition. By hiding each caching bird: how to re-find
you may notice a hierarchy, with prize discreetly in moss, leaf its stash. How, up to a year
certain birds displacing others. litter, crevices in the bark of a ater, does a species with a
Close to the bottom of this tree, or cracks in a wall or fence ea-sized brain perform these
pecking order will be the coal post, they can accumulate more mental gymnastics?
tit. This small, humbug-headed food than birds that simply
bird has to be sneaky to outwit peck away until full. Brain food
the bullying blue and great tits. This strategy is so effective In fact, the hippocampus
Coal tits dash and grab – that related species, such as (the part of the brain associated
flying in and quickly out. Follow the marsh tit, can cadge up to with spatial memory) of food-
them and you’ll see that though a morsel a minute – that’s a storing species grows up to
they might sometimes sit away staggering 50–60,000 food 30 per cent bigger over autumn
from the feeding frenzy and items each autumn. and winter, swollen with newly
delicately dismember a snatched DID YOU This number might generated brain tissue and
peanut or sunflower heart for KNOW ? be as much as three nerves. As the bird reaches
immediate consumption, most In winter, coal tits form times as high in a peak memory capacity, it is
often they’ll whizz off to some large flocks to scour bumper ‘mast’ year thought that parts of the brain
secret corner of the garden and woods and gardens – a situation that we holding old memories are
return minutes later to repeat for food – which, may be replicating overwritten with new neural
the process – engaging in what of course, they with feeders in our material like a computer disk.
stash.
scientists call scatter hoarding. own gardens. Far from ‘bird-brained’, these
Coal tits don’t guard these pecies are able to recall an
hidden morsels – but then they ncredible number of stash
CONTRACTION OF THE CRANIUM don’t really need to. Though a pots. Jays can remember the
competitor may sneakily follow ocations of between 20 and
Shrews don’t waste brain power in the winter.
a tit to a stash, or randomly 0 per cent of their caches.
Shrews don’t hoard food, and re-absorbs that organ for the discover one, such a loss is forget the locations of some of
Inevitably, though, birds do
Illustrations by Peter David Scott/The Art Agency they have to do cent. This is known puts all its nuts in one basket As a result, these birds make
winter, decreasing the volume
can’t hibernate in winter when
negligible compared with that
food is scarce – so
its head by 20 per
of
experienced by a species that
their stashes; in addition, some
irds are eaten by predators, and
as Dehnel’s
something drastic
ome hidden seeds are simply
and creates a larder, risking the
phenomenon.
to survive. A
lot if its hoard is discovered.
ot needed, so may germinate.
large proportion
If the shrew
Corvids are also well known
survives the
of a shrew’s
a contribution to the spread of
for hiding excess food for later
winter, its brain
energy budget
consumption. The European
hazel, oak and beech woodland.
is expended on
its brain, so it
in the spring.
acorns during one autumn.
is a naturalist, author and TV presenter.
October 2018 grows again jay can hide as many as 5,000 NICK BAKER BBC Wildlife 17
