You Call That a Bird's Nest?

When talking about birds' nests, what comes to mind? Probably the typical thing you can see by looking up in the trees, made of twigs and other things that were liberated for the cause. Then, the expectant mother lays eggs and keeps the eggs warm with body heat until they hatch. We've seen the scenario. This does not fit the malleefowl.

Leipoa ocellata (malleefowl) image credit: Wikimedia Commons / Peterdownunder (CC BY-SA 3.0)

This chicken-sized bird is found in 'Straya and other neighboring areas. It doesn't quite build a nest. Instead, it builds a mound (that is like a housing project) for the purpose of incubating the eggs. After the construction is completed and it's determined to be in the proper temperature range, Mom lays an egg, and does it again every week or two for six months. Dad keeps the temperature at the right level by making adjustments in the mound. Egg design, knowledge of temperature, maintenance, unique features, and more all indicate the work of the Master Engineer and thwart evolution.

What if your life depended on your parents’ ability to discern a narrow range of temperature without using a thermometer? If you were an unhatched Malleefowl chick, belonging to the family of birds known as incubator birds, then your life would absolutely depend on the ability of your parents to incubate their eggs between 29 to 38 degrees Celsius (average 33 degrees Celsius).

Incubator birds don’t warm their eggs by sitting on them. Instead, they build a sort of “greenhouse.” Although the humble size of a chicken, the industrious Malleefowl take on the engineering task of constructing an impressive mound for the eggs, digging about 3 feet deep and 10 feet wide (approximately 90 by 300 cm) with their large feet. Then they fill the depression with all sorts of organic material—sticks, leaves, bark, grass, sand, and soil.

To read the rest, click on "The Incubator Bird: Nest Engineers"