Re the thread about bird "intelligence", use of tools etc , I'd like to
share a story told to me the other day by a friend, Phill Bloomfield, who
was working on the construction of the Thompson River Dam in the Latrobe
Valley in the mid 1970s.
An enormous quantity of overburden was being excavated at the dam site, and
the edible riches thus exposed regularly attracted up to 20 or 30 Laughing
Kookaburras. These canny birds didn't forage in amongst the excavation as it
proceeded, no doubt something of a hazardous undertaking, but instead
harvested the pickings by riding on the backs of the fleet of trucks which
were employed all day every day to transport this 'waste material' to a
tipping site about 2 kilometres away.
OK, this is bright enough, maybe comparable to birds feeding from a host
mammal's parasites while it is in motion, or willy wagtails using a horse as
a vantage point from which to hawk at the insects it, (the horse), disturbs
while it grazes.
But, Phill relates that the kookaburras would feed all the way to the tip
site, leaving the truck only when its load was tipped over a 60ft cliff
face, and then fly over to the nearest empty truck to ride back to the
excavation site - three or four kookaburras to a truck in both directions!
This went on all day every day.
Surely this second stage of the cycle takes the kookaburras well beyond just
clever optimising of a food source, in that they were utilising an empty
truck to take them to a known destination as a preferred alternative to
flying a couple of kilometres. Not just taking a random ride, but using the
empty truck as a considered step with the object of repeating the whole
process.
I saw something about tool using on a National Geographic programme the
other night, but I can't recall their definition. Does the kookaburras'
return journey fall far short of this?
Bill Jolly
"Abberton", Helidon, Qld
ph 07 46976111
fax 07 46976056
email:
Visit our website at: www.abberton.org
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