70 Australian Geographic
edges at very low tides and entering through holes caused by
corrosion or storms. One fox in the reserve Heirisson Prong killed
33 bettongs before it ate a poison bait.
Conservation today is often about barriers of some kind,
helping species breed inside aviaries, pens, cages, terraria, aquaria
or large enclosed reserves. Australians are world leaders in fenced
conservation, and captive breeding has saved some of our treas-
ured wildlife from certain extinction. Dwell on the successes
and a heart-warming story can be told.
But no system of protection is guaranteed; this work is com-
plex, demanding and sometimes fails. Fences don’t look after
themselves, and animals can be difficult to breed and impossi-
ble to return safely to the wild. At Arid Recovery, success itself
has become a problem. Burrowing bettongs, breeding like
rabbits to 10 times natural densities, are trashing the vegetation
inside, ruining habitat for other rare tenants. They worry Kath
more than rust patches on fences.
A
T MELBOURNE ZOO I’m led behind the public area to
a humble shipping container to hear a different cata-
logue of problems. Before he goes inside, Deon Gilbert,
threatened species officer for Zoos Victoria, dons an apron,
plastic gloves and gumboots. While I stay at the doorway,
he holds up little tadpoles wriggling in plastic cups and tiny
Baw Baw frogs in moss-laden vivaria.
Being creatures partly of land and partly of water, frogs can’t
be bred without discovering the separate needs of eggs, tadpoles
and adult frogs. That can take years, and time is not on Deon’s
side. Naturally confined to only one mountain in Victoria, the
Baw Baw frog is down to one wild colony on one stretch of
one stream deep inside a towering mountain ash forest. It has
been eliminated from other streams by logging and chytrid,
a deadly fungus that has been decimating frog populations
worldwide. The gear Deon wears is for disease hygiene.
“Just because you can rear something doesn’t mean you can
get good adults,” he says. Deon was able to raise young frogs
from wild eggs back in 2013, but some died and the rest were
unhealthy. The problem, calcium deficiency, was resolved by
switching the frogs from meals of crickets to a diet of woodlice,
pill bugs and springtails.
Deon then found that adult Baw Baw frogs won’t breed unless
kept below 5°C for some weeks. But when their shipping container
home is cooled, the prey they’ve been provided with stop mov-
ing and the frogs can’t locate them. The food species are sourced
from Melbourne and will have to be replaced with high-calcium
versions from Mt Baw Baw that like the cold. The learning curve
is slow because this frog’s annual breeding season only lasts five
or six weeks – one wrong detail costs a year’s work for the species
while Deon strives to get it right.
Taronga Zoo has no trouble feeding its endangered frogs.
I follow keeper and herpetologist Dean Purcell into a drab office
to a door labelled “Grasshopper Room”. Inside, courting crick-
ets chorus from large plastic boxes, transporting me, if I close
my eyes, to a grassy field on a hot summer evening. Other boxes
contain thousands of moving dots – baby crickets, ideal tucker
for baby frogs. The corroboree and yellow-spotted bell frogs
bred at Taronga thrive on them once they are dusted with
vitamin and calcium supplements. Following Deon’s lead,
Dean now has a woodlice room as well.
Taronga learnt in five years how to breed corroboree frogs,
and Deon is close to breeding Baw Baw frogs, but is not there
yet. An earlier effort by both zoos to breed sharp-snouted day
frogs failed; the species is now regrettably extinct, its fate a stark
reminder of what’s at stake.Burrowing bettongs might look small and innocuous, but
they aren’t the best of tenants. In fenced reserves they can
rapidly denude large areas of vegetation.Melbourne Zoo amphibian specialist Damian Goodall,
team leader for operations of the reptile and amphibian
department, holds a female Baw Baw frog.PHOTO CREDITS, FROM LEFT: JANNICO KELK; ZOOS VICTORIASCIENTIFIC NAMES, FROM LEFT:Bettongia lesueur; Philoria frostiBut no system of protection is guaranteed; this work is
complex, demanding and sometimes fails.