Malleefowl

Most people who spend time in mallee country never see a malleefowl at all — what they see is its handiwork. Somewhere in the low grey scrub behind the Mount Lofty Ranges, a shy, chicken-sized bird, dun and finely barred, has spent the better part of a year tending a mound of raked sand and scraped-together leaf litter that can end up the size of a small car.

Inside that mound is the trick. A malleefowl cannot brood its eggs with its own body, so it manages the heat around them instead, by beak and by foot. Buried leaf litter at the mound’s core rots slowly through winter and gives off warmth from below; the sun beats on the sand from above; and the bird’s whole job, for months, is to hold those two competing heat sources steady at exactly the temperature its eggs need. It vents the mound when the core runs hot, rakes sand back over to trap warmth when it runs cool, and scrapes on a skin of chilled morning sand ahead of a fierce summer day, seeming to read all of this by taking a billful of mound material into its mouth — an oven thermometer built into its own face. No malleefowl chick ever meets its parents: it hatches deep in the litter, claws its way up through a metre of sand, and walks off already feathered enough to fly and fend for itself, one of the very few birds on Earth that incubates this way.

That whole strategy depends on a landscape running to a fire clock the bird cannot control. The Murray Mallee behind Adelaide is precisely the sort of country its mounds need: deep, undisturbed leaf litter under long-unburnt scrub, the kind of ground biological surveys of the region have mapped quadrat by quadrat (Foulkes 2000). But that litter and cover take a long time to rebuild after a fire, on much the same slow schedule that governs the region’s spinifex (Haslem 2011). Burn the mallee too often, or clear it, and there is no litter left to rot, no cover to hide the mound, and no long interval left to build one in. Which is why the malleefowl is listed as vulnerable, in South Australia and nationally, and why its best strongholds are the very places — Ngarkat among them — that the plough and frequent fire have never quite reached (Ngarkat 2004). Find a mound in working order, then, and you have found something rarer than the bird that shaped it: a stretch of mallee old enough to still run the fire clock the malleefowl was built for.