the water levels will be right for the Magpie Geese to nest.
But it the rain keeps on coming,
their nest sites may be flooded.
The mother crocodile is already committed.
All she can do now is hope that her chosen nest site is high enough,
and that the rising flood doesn't
drown their young before they hatch.
For the Agile Wallabies,
the Wet is the time of greatest stress.
Permanently saturated fur is bad enough
but worse, it's becoming clear
that their grazing grounds in the lowlands soon beyond the water
But there's nothing unusual, as yet,
about these cataracts of water pouring into the flood plains.
If there's such a thing as an average year in the Top End,
this could still be one.
As one rain cloud dumps its contents onto the land,
the next is already moving in from the ocean.
Soon the rivers are breaking their banks,
and sheets of water are spreading out across the plain.
And still the rain falls.
These ants normally live in tunnels and chambers
they've hollowed out within the termite mound.
The water laps ominously at the base of the crocodile's nest.
The rain keeps on coming.
It's early February, and the monsoon trough has
been stationary over the north for weeks.
The temperamental climate of the Top End,
which the year before brought
barely enough rain to fill the billabongs,
has swung to the opposite extreme.
This, it now seems certain, will be a year of the Big Wet.
The water is racing metres deep through
woodland that is barely flooded at all in normal years.
Every land animal that has not sensed the Big Wet coming,
and escaped in time to higher ground, is now in deadly danger.
The Goanna is an expert swimmer
but the tossing flood is tough going.
But the Goanna's refuge may be only temporary
the water is still rising.
The floods drive everything into the trees,
including Australia's least welcome immigrants.
A feral domestic cat
the deadliest killer of small marsupials.
And the wild pig,
which infests the wetlands in its tens of thousands.
The old boar leads herd off to South with off spring
swimming for their lives.
The green tree ants' nest is usually far above the ground.
Now it's in danger, too.
A grasshopper sheds its old skin...
But it expose at the tree tops the bright green
and shed up is easy prey for birds.
And this Dusky Plains Rat will be one more meal,
when he wants it,
for the water python already gorged on stranded prey.
Balanced on a floating log,
another Dusky Plains Rat is trying to survive by eating bark.
During the Dry it lives in cracks and burrows in the warm earth.
Wet, hungry, and with nowhere to hide from predators,
it has not long to live.
The baby kingfisher, swept form its nest, will surely drown.
But there are winners, too.
For the owl, there's a meal cowering on almost every branch.
At last, in mid-February, the rains begin to ease,
but the calm may be deceptive.
In many years the monsoon trough retreats,
only to return again laden with still more rain.
Meanwhile, for the survivors,
there is nothing to do but wait.
The goanna has abandoned the trees for a more permanent refuge.
Creatures adapted for concealment in green grass are
all to visible on the bare rock.
The goanna will not be short of food.
But with the floods now lapping
at the very walls of the escarpment,
other creatures are in danger of starvation.
The Narbelek is one of the smallest of
Australia's rock wallabies.
Unlike the goanna, it's not a refugee the crags
of the escarpment are its permanent home.
Normally, it feeds at night on the grasses below the escarpment.
Now it's forced to venture out
in daylight to browse on the sparse vegetation of the sandstone.
As it feeds it keeps timid eyes out for predators.
Anything without wings that's survived so far is
trapped on islands of high ground.
And that includes the human inhabitant of the north.
This is Australia's National Highway One,
which circles the continent.
It was engineered to cope with the worst of floods.
Now it too has fallen victim to the Big Wet.
Here the damage is visible,
but in the vastness of the sparsely populated Top End,
the full cost to Australian wildlife will never be known.
In normal times this road is the only link
between the isolated communities
of the empty north and north-west.
Now they, like the wildlife around them,
are cut off form their normal sources of supply.
In the Kimberley,
the little town of Fitzroy Crossing was isolated twice during
this very heavy monsoon season.
Throughout the north, the cost of damage to roads, fences,
stockyards and buildings ran into millions of dollars.
In the bush, thousands of head of cattle were lost to the floods.
As the floodwaters slowly ebb,
they leave exposed the death and destruction they have caused.
The wallaby didn't make it to the high ground in time.
The rain has almost stopped.
The run-off from the plateau has eased.
Through open woodland and grassy flat,
the water races back into the rivers.
Under a plenty of willing jaws to tie up behind
the retreating flood
It's mid-March, a treacherous time.
There's still a chance that the monsoon trough will return,
or that a cyclone will roar in from the sea.
But meanwhile, the wetlands are swamps once again,
and not an inland sea.
There are Eleocharis grasses for the magpie geese to nest in,
and at last the water levels are right.
The goose, of course, lays the eggs
but the gander does much of the parenting.
He puts the finishing touches to the nest.
He spends long periods incubating the eggs
an anxious time, for there's still a chance
that the returning rains will wash it all away.
And when, thirty one days after the first egg was laid,
the hatchlings fight their way out into the world
it is he who guards them from predators.
A conscientious father can make a huge difference
to the hatchlings' chances of survival...
...which is perhaps why often two females will share a male,
and a nest. Each goose will have fewer chicks than
if she had a nest to herself...
...but these co-operative trios are perhaps such
successful parents that it's worth the sacrifice.
It's late March, and the monsoon season, Gudjewg,
is giving way in the Gagadju calendar to the season of plenty
and knock-em-down storms Bang-Gedeng.
Washed clean and sparkling,
the wetlands burst into flower.