Secrets of the Sarus Crane

Throughout a typical Tablelands winter day, author John Grant follows Sarus Cranes from a misty swamp at dawn to their farmland feeding grounds, and finally experiences the exciting yet peaceful twilight scene as hundreds fly in to roost at a large crater wetland. On the way, he outlines some of the mysteries surrounding the origins, history and life cycle of Sarus Cranes in northern Australia. Is the Brolga's increasingly observed larger cousin a recent arrival from Asia or an overlooked, longtime resident on the move?

This article was published in a special Wetlands edition of Wingspan, former membership magazine of Birds Australia (now BirdLife), Vol. 14:4 December 2004. The original text is reproduced by permission, edited for web by Ozcranes.

Secrets of the Sarus Crane

by John Grant

Part 1: Morning scene

A cool breeze begins to stir the thick blanket of mist. It is just after dawn but with no sign yet of the watery sunrise that comes on most mornings at this time of year. The bleak scene is far removed from the more familiar, balmy images of north Queensland winters. Here on the Atherton Tableland, a passable winter marks the annual cycle, in addition to the more widespread wet and dry seasons. At an elevation of 700-800m, mid-year frosts strengthen the feeling that this is a world quite different from the humid lowlands of the Cairns area, a short drive down the escarpment.

The foggy depression is quiet, just the odd squeal of a swamphen hints at the waking wetland within. A muffled flapping arises and a group of ibis breaks through the mist, departing to forage for the day. No sooner has the silence resumed than the air is rent by a violent trumpeting: wild and startling. The sound is unmistakably that of a Sarus Crane: deeper and more rolling than the gentler voice of the Bolga. The two Australian cranes often share feeding and roosting areas on the tablelands, but at at this site, close to my home, Sarus Crane have dominion. The call is quickly answered by another, then by two or three more birds in a brief, jangling chorus.

The sun begins to break through and the deep crimson heads of two cranes appear above the carpet of mist. As the birds advance uphill from the marsh, their necks come into view, showing the characteristic Sarus Crane features – bare red skin extending about a foot down the neck, and a smoothly concave throat, with no sign of the dark wattle or ‘dewlap’ of the Brolga. The height and bulk of the birds becomes apparent as their shoulders emerge – the Sarus Crane is the tallest flying bird on earth, a giant even amongst its lanky family. It is the race from India that claims this title for the species, while the distinctly smaller Australian race gilliae, though no midget at up to 1.5m, can be outstripped by the Black-necked Stork (Jabiru), with which it shares the swamps.

Despite its imposing stature and the high conservation profile of most crane species (11 of the world's 15 species are listed as threatened or endangered), the Sarus Crane remains one of Australia's most poorly known birds – at present we have only the vaguest idea of its population size and status, ecology and distribution. While this may be true of many Australian birds, it is unusual for one that spends half the year in such a densely settled and easily accessible region. Indeed, the Tableland's population is the only significant wintering concentration known.

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Part 2: From small beginnings

In Part 2, John continues his journey through a day with Sarus Cranes on the Atherton Tableland, far north Queensland, and introduces two current studies exploring the mysteries surrounding this large and elegant, but little-known Australian bird.

The breeding grounds of the species include the wetlands of Cape York Peninsula and the Gulf of Carpentaria, where the crane was first recorded for Australia (near Normanton) in 1966. Sarus Cranes have been wintering on the tablelands – or perhaps more correctly, spending the dry season here – since at least the following year, 1967, when 23 birds were seen. Their numbers have gradually risen since, but it is only in the past seven years that any attempt has been made to make a systematic count. Tablelands ornithologist, Elinor Scambler, has coordinated an annual count at roosting sites each October since 1997, giving us a preliminary population estimate. With teams of observers covering all the known major sites, the count in most years has produced a remarkably consistent tally of around 1,700 birds. (Some smaller roosts are always missed for want of more observers, and new sites are discovered in most years, suggesting that improved estimates can be achieved if the counts are continued with increased observer support.) But where else do the cranes winter? The count in 2001 yielded a bumper total of about 3,000 birds, hinting at the possibility of other populations that normally winter elsewhere. Small numbers are seen at Cape York and Gulf of Carpentaria sites in the dry season, but these vast areas have been poorly covered historically due to their remoteness.

The nameless swamp I am watching this morning is one of the smaller roost sites, with 20-30 birds flying in at sunset on most evenings between May and November. The two visible cranes depart with more bugling calls, taking off after a short, awkward run-up and quickly transforming into the most graceful of fliers. As the mist thins, silhouettes of more cranes appear, again walking away from the marsh. Some call quietly as they go, and then they too lift off, in twos and threes mostly. Flying steadily they head purposefully west, towards the agricultural areas of the tablelands.

An hour later I am driving in the same direction, through one of the brilliantly crisp mornings that make the chilly tableleland nights more bearable. The patchily forested eastern parts of the plateau give way to an intensely fertile volcanic landscape – largely cleared and remarkably flat but for the shallow hills of the old shield volcanoes and a sweeping arc of smaller, steeper cindercones, familiar locally as the ‘Seven Sisters’. The volcanic activity that formed this landscape finished as recently as 14,000 years ago – graphically described in indigenous stories from the area – and has resulted in one of the most productive farming areas in Australia. Maize, peanuts and potatoes are among the most widespread crops, with sugar cane also becoming prevalent in recent years. The cranes are particularly attracted to the maize fields, and post-harvest, these typically harbour the largest flocks. Smaller groups also regularly feed in pastures, often alongside cattle. Today I find a flock of almost 200 birds in a regularly frequented corn stubble field, and spend some time scrutinising them through my spotting scope. Over the years it has become possible to reliably distinguish several age classes of birds, making a demographic study one of my principal goals.

Next: Parts 3 & 4» ‘Invasion or expansion?’ and ‘A craterful of cranes’

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About the authorJohn» is a professional zoologist working in teaching and research, with a particular interest in Sarus Cranes. He has been studying the recruitment rate and feeding substrates in the wintering population of Sarus on the Atherton Tablelands since 1997. Both studies have reached the significant stage of 20 years of survey data, and writing is in progress. John's other work includes Sarus breeding ecology in the seasonal Gulf of Carpentaria wetlands and the maturation stages for Australian Sarus. John is a member of the the Crane Specialist Group and other articles on his long term work with Sarus Cranes can be read on Ozcranes.

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