moundnesting

Mound nesting is a reproductive strategy used by certain birds in which eggs are incubated not by parental body heat but by the heat produced within large mounds of vegetation, soil, and other organic material. This approach is most closely associated with the megapodes, a group of ground-dwelling birds native to Australasia and parts of Southeast Asia, including species such as the mallee fowl and various brush-turkeys.

Birds constructing mound nests build and maintain sizable piles at breeding sites. The mound’s temperature and humidity are influenced by ambient conditions and by the birds’ activities, such as adding fresh material or adjusting the mound’s structure. Incubation relies on the heat generated by the microbial decomposition of the organic matter inside the mound, and the birds may regulate the climate to some extent by modifying the mound’s composition and moisture. The incubation period varies among species and environments, lasting from several weeks to months.

In megapodes, eggs are typically laid in a clutch that may be deposited over an extended period into the mound. The eggs are relatively large compared with body size and have thick shells. When embryos are ready, chicks hatch and break free from the mound, becoming precocial and capable of independent foraging shortly after emergence. Parental involvement after laying is limited compared with many other bird species.

Ecology and conservation concerns for mound-nesting species include sensitivity to habitat changes, fire regimes, and introduced predators. Loss of suitable nesting sites and disruption of mound microclimates can impact reproductive success. Some populations are declining, prompting conservation measures focused on habitat protection and predator management. Related topics include megapode biology and bird incubation strategies.