Pelican stories for the future - Ockham's Razor

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Subject: Pelican stories for the future - Ockham's Razor
From: "Tony Lawson" <>
Date: Fri, 1 May 2009 09:29:54 +1000

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.

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