The Australian brush-turkey

Somewhere on this coast, right now, in the damp litter of a gully or the mulch of a suburban garden bed, a big dark bird with a bare red head and a swinging yellow wattle is raking backwards with both feet, hurling leaves and soil into a heap behind him. Give him a few weeks and the heap becomes a mound four metres across and a metre high, a compost pile the size of a small car, and a nursery. This is the Australian brush-turkey, and it does not incubate its eggs. It lets rot do the job instead.

The brush-turkey belongs to the megapodes, the “big-feet,” an ancient lineage of mound-builders that long ago handed back one of the defining chores of being a bird. Most birds press a warm body to a clutch and hold it there through the long patient days of incubation. The megapode male does something stranger and, in its way, more ingenious: he buries the eggs deep in his heap of rotting vegetation and lets the heat of decay do the incubating — the very warmth that rises off a backyard compost bin, harnessed as an oven.

The mound impresses; tending it is the real feat. The eggs must be held close to the mid-thirties Celsius, and the male keeps them there by hand, or rather by bill, for months on end, thrusting his head into the pile to read its temperature, then piling on fresh litter when it cools or scraping the heap open to let heat escape when it climbs too high. He is a living thermostat in feathers, a solitary obsessive who checks the setting daily and turns his compost all season.

What hatches from it is stranger still. The chicks break out of the shell deep in the dark and must dig their own way up through the mound, an exhausting slog of many hours, clawing upward through the litter that hatched them. They surface on their own, fully feathered and independent, never having met a parent, and can flutter up into a tree within hours of reaching the light. No brooding, no feeding, no lessons. The parenting, such as it is, was all done in the building.

Hold the brush-turkey up against the coast’s specialists and you can see why it is here in force while they fade. The logic of dependence is worked out elsewhere in this library. Here is the cheerful exception. Where the koala is staked on a particular leaf and the acid frog on a particular chemistry, the brush-turkey is staked on almost nothing in particular: leaf litter to build and heat a mound, a little moisture to keep the compost working, shaded ground to rake, and whatever fallen fruit, seed and grub it turns up along the way. Those needs are cheap and near-universal. It is happiest in the deep, damp litter of the rainforest, but it spills out through the wetter gum forest, the scrubby edges and, more and more, the mulched suburbs. A broken, edge-riddled landscape that would starve a specialist is, to a brush-turkey, simply more of the ground it likes.

That is not idle theory. Hunted hard by earlier generations and pushed back from the settled districts, the brush-turkey has come roaring back and moved into town: in Brisbane and Sydney alike the ground it occupies has spread steadily since the 1960s, and lately into the most built-up, least leafy suburbs of all (Hall et al. 2024), to the mixed feelings of gardeners whose flowerbeds it rearranges each morning. In a fauna full of decline, that is cheering. An odd, robust, all-purpose way of life can settle into the human landscape and thrive there. For the specialists, the ledger of needs against supply keeps coming up short. For the bird raking up the mulch beside the barbecue, it comes up long.