This is a very interesting talk, but it doesn't provide an answer to
the question 'How do they know there's water available in usually dry
desert areas?'
John Leonard
2009/5/1 Tony Lawson <>:
> Listen Now - 26042009 |Download Audio - 26042009
>
> Dr Libby Robin from the National Museum of Australia in Canberra is Senior
> Editor of a recently released book called Boom and Bust: Bird Stories for a
> Dry Country and today she ponders why pelicans fly inland after rain, even
> though they never saw it falling. How do they know there's water available
> in usually dry desert areas?
>
> Robyn Williams: I suppose you've seen those thrilling pictures in the papers
> of thousands upon thousands of pelicans gathered in the centre of Australia.
> They've flown to the wet, and once they're there, they do what pelicans do
> so well: breed like there's no tomorrow.
>
> Now if you look at a great big pelican, with its crew cut, philosopher's
> frown and vast undercarriage, you're impressed, yes, by its sheer weight as
> well, but despite the look and the hefty size, it doesn't tell you how they
> know when to fly, or why they should leave the seaside, which is surely
> pelican heaven, to go off to some red sand desert, just because it's flooded
> for a week or two.
>
> Well Libby Robin has some answers. She's senior editor of the book Boom and
> Bust: Bird Stories for a Dry Country, and she has a remarkable story to
> tell.
>
> Libby Robin: Why do pelicans fly inland after rain, even though they never
> saw it falling? They somehow 'know' that this is the moment to go and breed.
> When they go inland they find huge lakes, pulsing with life, in country
> that's most often waterless and without fish. Knowing when desert rivers are
> flowing and the fish are breeding is essential to the survival of pelicans.
> They take the chance to breed when the moment is right.
>
> Pelicans have evolved to work with the 'boom-and-bust' cycle of the
> Australian desert. They have adapted to the world's most variable climate,
> the climate of inland Australia. It is this that saves them from being an
> endangered species at a time when their habitat is changing rapidly.
> Pelicans know how to find and exploit the resources of marginal places that
> are only sometimes wetlands.
>
> Pelicans in coastal areas live with new difficulties. There are a lot more
> people living near them. Urban and semi-urban settlements now sprawl through
> their former breeding haunts. Wetlands are good for pelicans, but bad for
> developers, so they are often drained. In rural areas, the chemicals added
> to farmlands and the responses of acid sulphate soils to agricultural
> exploitation pollute many remaining wetlands.
>
> We are lucky that despite all the changes we still see these splendid birds
> in coastal areas. While people demand the certainty of dry land for housing,
> and seasonal agricultural production, pelicans have an alternative rhythm.
> They need places to fish all year round, and places with extra resources to
> breed and feed hungry chicks. Now that coastal wetlands are severely
> limited, the pelicans turn to alternative inland wetlands, where, for short
> times, there are extraordinary resources to grow and fledge their chicks.
> The opportunity to breed comes, not annually in spring, but when the fish
> are plentiful. And it must be taken quickly. Pelicans survive because they
> can breed at the times and places when the fish breed; as long as people
> don't mess up these ephemeral inland wetlands too.
>
> Pelicans are not the only birds that have adapted to both the people and
> climate of Australia, but they are familiar. We know them from their
> beachside haunts, big, clumsy birds out of water, gracious in. We know them
> one at a time, they are each around 8 kilograms. The ecologist, Julian Reid,
> tells us about different pelicans, inland pelicans, pelicans in bulk. He is
> watching the rhythms of inland Australia as he lies on his back while
> thousands of pelicans take off above him. Thousands of kilograms of bird
> mass soaring upwards in spirals, riding the thermals, then at a great height
> one individual bird breaks out and the rest follow in a V-shape toward a
> distant lake. Successive skeins of birds repeat the pattern in a staged
> manner to the new feeding ground. These are familiar birds made unfamiliar
> by sheer numbers.
>
> The idea of a Boom-and-Bust rhythm is abstract: it needs a pelican to
> remember it with. I can swat up abstractions for exams, but they disappear
> quickly afterwards. Many years ago I tried to teach myself Spanish. I can't
> remember any grammar or vocabulary now, but I can still sing every word of a
> little Spanish song from the tape. It is the unconscious mind that remembers
> songs and stories. How do we engage our unconscious with the big
> environmental changes of our time? The answer? Stories.
>
> In a land where floods and droughts are natural parts of a bigger ecological
> cycle, birds depend for their survival not on regular rains but on how long
> they can stretch out their resources between big flooding events. They need
> to seize the booms and lie low in bust-times.
>
> Drought is normal in Australia. In the arid lands of Australia, 'normal'
> ecosystems do not follow the annual seasons, as they do in other parts of
> the world, but rather boom (or 'pulse') after rare rain events. Flowers,
> seeds, seedlings, baby birds and other animals all follow at different times
> after the events, but the 'pulse' produces activity, and then inactivity.
> During the long dry times between booms, the natural systems wait. The
> technical term is that they 'reserve' their energy. They are waiting, not
> strictly 'busted'. But if the wait is too long, they will not survive.
>
> How long can they wait? Birds and other creatures, adapted to the long
> breaks between rain in arid Australia, have evolved special coping
> strategies. It is not simply that it's a long wait but that it is an
> uncertain one. It's not like a bear hibernating for the winter months, then
> waking in spring. There are no regular seasons in this country. Rain is
> carried south on the monsoon and sometimes blown north by sub-Antarctic
> winds. But this country is at the extreme edge of both. The survival of
> creatures depend on how well they can wait and cope with the uncertainty of
> the wait, and then how quickly they can respond to opportunity, whenever it
> arises.
>
> Our new book, Boom and Bust: Bird Stories for a Dry Country, tells some of
> the stories of the workings of exceptional Australian ecosystems through our
> charismatic birds. We are no longer writing about a 'natural' system, all
> our birds live with people to a greater or lesser extent, so we need history
> as well as ecology to tell these stories. Some birds, like the pelicans,
> adapt to people and cope well with the uncertainties of never knowing when
> the bust (or resource poor) time will end. But added to the old
> uncertainties for which birds have evolved strategies are new uncertainties
> created by the great changes wrought in the landscape by humans; these
> changes are in historical time, not evolutionary. And we are still trying to
> make sense of this changing history, and learning how birds and other
> creatures are responding to human-induced change.
>
> The first wave of human settlement was Aboriginal people who arrived about
> 55,000 years ago and burned vegetation to improve their hunt. These people
> profoundly changed the vegetation patterns of the landscape. Human fires
> changed the food sources available to birds as well as the structure of the
> vegetation.
>
> When times change, it is better not to be a fussy eater. The huge duck-like
> bird, Genyornis, taller than a man and weighing about 275 kilograms, was, it
> seems, too particular about what it would eat. It died out about 45,000
> years ago, probably because its preferred food, chenopod shrubland (that's
> saltbush and bluebush) became increasingly replaced by grasslands and open
> Eucalypt woodlands. Without its preferred tucker in large quantities,
> Genyornis did not survive. But Emu, another big bird that lived in some of
> the same places in the Australian desert, adapted. It seized on available
> food sources and learned to eat them. Changing its feeding pattern ensured
> its survival.
>
> Then the second wave of humans arrived just over 200 years ago and
> introduced European farming practices to the wide expanses of inland
> Australia. The adaptable Emu discovered a taste for wheat and ate it with
> enthusiasm, much to the chagrin of battling Western Australian farmers in
> country near the rabbit proof fence. In 1932, the Commonwealth Minister for
> Defence declared an Emu war. He sent in the Seventh Heavy Battery of the
> Royal Australian Artillery with two Lewis guns and 10,000 rounds of
> ammunition. The opportunist Emu had made wheat-growing tough, but its
> uncanny ability to run and dodge machine-gun fire totally embarrassed the
> military. You can't fight opportunists with fixed and inflexible artillery.
>
> In the northern hemisphere, where most of our economic and many of our
> ecological models are based, there's a historical certainty that resources
> come and go with the sun: spring brings new growth, autumn harvests. Global
> and national financial systems are similarly based on annual cycles that
> draw on the deeply seasonal agricultural past of dominant western nations.
>
> As global climate change affects ecosystems everywhere, certainty is
> increasingly eroded: seasons fail, food supplies are no longer reliable, and
> extraordinary weather patterns bring disasters on unprecedented scales. Now
> uncertainty does not just affect marginal places like the Australian arid
> zone. It is spreading and changing the functionality of places where
> certainty used to be the norm. Boom times no longer appear annually on the
> calendar with the harvest. The world seeks new ways to live with
> uncertainty, to adapt to disasters and to wait out the increasingly
> uncertain stretches of time between good seasons.
>
> Australian Aboriginal people have a different calendar - and are consummate
> story-tellers. They watch the birds and flowers and understand the structure
> of each year on its merits. 'When the brolga sings out, the catfish start to
> move', Daly Pulkara told Deborah Rose at Yarralin in the Northern Territory.
> Tellers create a calendar, but the calendar is not cyclical or certain,
> rather interconnected and ecological. The coming of rain, of fish, of edible
> seeds is each an important season, but it is not necessarily annual. The
> order of events is knowledge that is embedded in country; events are
> interdependent. This is the story of a calendar that waits. And people who
> remember stories.
>
> In uncertain times, we need Bird Stories for a Dry Country. Not all birds
> are coping with all the new uncertainties. For the Nigh Parrot, the changes
> wrought by human actions are too much. The wait between resources has been
> too long. The story of the elusive 'fat budgie' of the inland continues to
> tantalise and many grim human stories have become tied to its fate.
>
> Most of southern Australia is a 'dry country' in broad terms. Even cheerful
> urban birds like white-winged choughs, have evolved strange social
> behaviours to adapt to drought. Like many Australian birds, they breed
> co-operatively, with many helpers at the nest. Choughs are an extreme case,
> however. They are obligate co-operative breeders: if there are chough
> babies, there must always be more than a pair of bird-parents. Babies are so
> precious in the chough group's world of limited resources that one group
> will sometimes gang up and conspire to kidnap babies from another. A bigger
> group has a greater chance of successful survival in tough times, in chough
> logic.
>
> Ecological systems have booms (opportunities) and times of reserve. Humans,
> like birds, need to know when to take opportunities to grow and when it is
> better to wait and conserve resources. The Global Financial Crisis has
> everyone talking about Booms and Busts. But it is always the busts that
> attract the attention: busts are 'abnormal', while booms are the default,
> the normal expectation. Good and bad economic times have always been
> interconnected and interdependent. And there is no certainty when the next
> bust will come. Human society has much to learn from stories of birdlife in
> Australia.
>
> Robyn Williams: Well that's one angle to Anzac Day I never thought of:
> having the army take on the emus, and fail. That was Libby Robin. The book
> is called Boom and Bust: Bird Stories for a Dry Country, published by CSIRO.
> And Libby Robin is at the National Museum of Australia in Canberra, by the
> way.
>
> http://www.abc.net.au/rn/ockhamsrazor/stories/2009/2551660.htm
--
John Leonard
Canberra
Australia
www.jleonard.net
"I rejoice that there are owls." Thoreau
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