|Australian Brush-turkey chick shortly after hatching and emerging|
from incubation mound and showing well-developed flight feathers.
Photo: Burke Museum.
Did you know that not all birds sit on their eggs to incubate them? Megapodes (family Megapodiidae)—a fascinating group of birds named for their large feet—cleverly harness environmental heat sources to incubate their eggs.
Depending on the species and location, megapodes may lay their eggs in burrows dug in sun-warmed beaches or geothermally active areas, or they may build large incubation mounds that function like compost piles and generate heat through decomposition.
Although most megapodes look like distant chicken relatives (they are), their unique incubation behavior has driven a suite of unusual adaptations, including:
- large feet to help them dig burrows or build mounds;
- thin, porous egg shells to help eggs “breathe” underground; and
- the ability for chicks to dig themselves out from under several feet of soil after hatching and emerge ready to fly and fend for themselves.
How did this odd incubation behavior evolve?