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THE GREAT
COUNT
While pastoralists and conservationists are
locked in battle over the fate of the 'roo,
a scientific aerial count is going on to find
out exactly how many kangaroos there are
I thought I
could pick a
kangaroo from a
tree stump. Now I
know better. You
have to know the
difference in or-
der to count
kangaroos from
the air, which is a
job that literally
causes you to
have nightmares.
"When I go to
bed, I'm counting kangaroos all night,"
said biologist Dr Judith Caughley, one of
the NSW National Parks and Wildlife
team with whom we flew in western
NSW.
Her day is spent skimming the bush at
250ft (76m) in a light aircraft. From this
height at a speed of 185 km/h, it's hard
to pick a sitting 'roo from a tree stump.
Counting kangaroos is harder than
scoring bull's-eyes in a fun parlour. I
tried one survey segment and was a
disaster, counting 18 reds and 39 greys.
Ranger-naturalist Peter Bayliss, sitting in
front of me, saw 36 reds and 247 greys.
lt takes about 50 hours of flying to
qualify as a counter, the trainee's count
being checked against that of a trained
observer.
"We see about 46 percent and allow
for that," said Judith. The counting
method was invented by her husband,
Dr Graeme Caughley, of the CSIRO, and
Dr Gordon Grigg, of Sydney University.
lt looks disarmingly simple. Streamers
are tied to wing struts on each side of the
high-wing monoplane. The gap between
the streamers represents a 200-metre
strip of ground below and the observer
counts any 'roos spotted in this area.
While the plane flies a straight course
for 120-140km, a buzzer sounds for
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Count team (from right) Peter Bayliss, pilot
Allan Gardiner, biologist Judith Caughley.
seven seconds
every 97 sec-
onds. During this
period, the ob-
server counts
kangaroos and
writes down the
total while the
buzzer sounds.
When it stops,
counting starts
again.
This timing,
allowing for the
aircraft's height and speed, gives a
count for each square kilometre.
How many kangaroos are there In
Australia? Owing to the inaccuracy of
earlier counting systems, official es-
timates range from 11 million to 45
million.
Scientists believe a uniform aerial
survey throughout Australia would keep
a constant, accurate check on the
kangaroo population. But at the moment
only NSW, South Australia and
Queensland use it.
The drought has obviously killed tens
of thousands of kangaroos. Others
driven by lack of water and food have
invaded western grazing properties,
towns and even airports.
Results of the survey could bring
about a better plan to control kangaroos
in future. "We want to maintain kanga-
roos in seasonal abundance, but not so
many as would cause harm to land-
holders," said Jack Giles, director of the
NSW Department of National Parks and
Wildlife.
The survey, now about one-fifth
completed, indicates that numbers of
grey kangaroos are down, probably
because of drought, but reds are up. '\¿¡
Story: KEITH FINLAY
Pictures: ERNIE McQUILLAN
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* Counting kangaroos as
the landscape flashes by

is harder than scoring

bull's-eyes in a fun parlour'

$