In this article, Rabbi Shmuel Waldman explores the remarkable incubation process of the Mallee fowl, a bird that uses a unique method to incubate its eggs. Unlike the majority of birds that use body warmth for incubation, the Mallee fowl relies on a mound of earth and decaying vegetation to create the necessary heat.
The Mallee fowl is an extremely unique bird in the way they incubate their eggs. To understand this, we must first think about how regular birds do their incubation. 99.8% of all birds incubate their eggs (a process of warming their egg(s)) by sitting on them, (or putting them on other places of their body where they also get direct body heat). The point of incubation is that their eggs all get incubated by the consistent body warmth of the parent bird(s). Hashem made it that for the egg (embryo) to miraculously turn into a live baby bird, it needs a consistent, specific amount of warmth. The birds lose their feathers in a specific place on their body (the feathers would block the proper amount of body heat needed to reach the egg) and in their place there develops a special patch underneath them, around the time when they will be laying their egg. From that patch, there comes out the correct amount of heat needed for the embryo in the egg to slowly develop and finally hatch into a baby bird known as a chick. Sitting on the egg is a fairly simple method of incubation. Most of the time it’s the female bird that does the incubating, but not always. Much more should be said about this but it’s not our topic now. (Like discussing how the egg shell is miraculously made in the chickens body and a million other miracles involved with the embryo turning into a baby bird.)
Along comes this male Mallee fowl (fowl means a bird) and it has a completely unique, and EXTREMELY DIFFICULT AND TIME CONSUMING way to incubate their eggs, that has nothing to do with their body heat. They put their eggs into a mound of earth! In this process, it’s mostly the male bird doing all the work. The female does very little.
Here is the basic process that they follow. In the fall time, the male fowl builds the initial foundational mound of mostly sand. The mound he builds can be up to 35 feet across and up to 15 feet high! He may move up to 3 tons of material (about the same weight as 6 to 8 cars) to build his mound over a period of a few months. Mallee fowl are also called Megapods, which means big foot, since they have especially large feet which makes it easier for them to kick up dirt to make the mound. Hashem has everything in the calculations. Besides their big feet, they are about the size of a chicken.
Then in the winter, the birds dig out of the top of the mound a crater about one meter (3 ft) deep by three meters (10 ft) wide. Then the male fills this crater with grass, leaves, and other vegetation. After this mound of vegetation is soaked by late winter rains, he digs a small egg chamber (where he will eventually put the eggs), and then covers the whole top of the mound with sandy soil thereby sealing in the moisture of the wet vegetation. That’s when the fermentation process starts. (Fermentation means that the leaves break apart and in the process, it releases heat.) The Mallee Fowl keeps checking the temperature of the vegetation by pushing his heat-sensitive beak and tongue into the mound. It may take up to 4 months for the fermenting vegetation to reach the right temperature (about 92°). When it is warm enough, that’s when the female will begin to lay her eggs into this chamber.
Each time the female is ready to lay an egg, the male removes the top soil so she can place the egg in the egg chamber. Then he immediately re-covers the mound with the soil. She may produce up to 35 eggs in a six- month period. The last egg takes an average of 60 days before its ready to hatch, so for close to 9 months he is constantly busy with taking care of the eggs! During the day the bird frequently pushes his beak into the soil to check the temperature. Then he adjusts the mound based on the temperature.
If he sees that the nest is getting too hot because of the rotting plants, he removes soil from the egg chamber to let it cool down. He will often spread out the actual soil so that it too can cool down. If the sun is making the nest too hot, he adds more cool soil for protection from the heat of the sun. If the nest is getting too cold, he will remove soil so that the heat of the sun can better warm up the mound. The Mallee Fowl keeps the nest within one degree of 92° F at all times! (The fact is that the chick can survive even if there’s a bit more of a deviation of the temperature for over a few days, but the mallee fowl is doing all it can to avoid much of a deviation, since a prolonged period of the temperature being off its mark of 92 degrees, does have the ability to cause the developing chick to die.)
Here’s 2 quotes about the Mallee fowl. One writer wrote, “I find it remarkable that a bird is able to estimate the amount of organic matter (grass, leaves and other vegetation) it must add to the heap of soil so that the heat generated by fermentation will be just enough to bridge the gap between the soil temperature and the temperature needed for the incubation. It almost suggests that these birds understand some chemistry.
This next quote came about after some scientists were trying, unsuccessfully, to confuse the Malle fowl by causing sudden, drastic changes to the temperature in the mound, which amazingly to these scientists, the fowl was able to re-adjust accordingly right away. “Our observations suggest that the bird knows what is happening inside the mound and vary their activity [by adjusting the amount of soil] deliberately” [accordingly to those unexpected changes that were made].
Each day, on average, the male puts more than five hours of work into transferring a huge amount of soil each day. It happens to be that the constant movement of the soil has an additional advantage: It keeps the soil loose, will is very helpful for the chicks that are ready to dig up and out of the mound when they hatch. In addition, the loose soil will provide some air for them to breathe while stuck in the mound for many hours as we shall talk about shortly.
Now, for this unique process to work, it’s amazing what these birds have to “know”. They must know that decaying vegetation can cause heat. (Did you know that? I didn’t!) They must know that they can use the heat of those chemical reactions of the fermentation of the vegetation for incubating their eggs! [Who says that they “chap”, they grasp, that eggs need heat to get incubated. The fact that most birds sit on their eggs in no way tells any bird that it’s the warmth that is needed. They just have instincts to sit on the eggs, so they sit.] They also know how to cause the vegetation to ferment, (which I don’t know.) More complex is the knowledge they must possess in how to adjust the decaying vegetation in a way that it can either get hotter, or colder, depending on what is needed to keep the temperature at the precise degree necessary for optimal chick development. Did you know any of this? Even using a thermometer, would you be able to keep the temperature within 2 degrees Fahrenheit of 92 degrees, day in and day out, for about 5 months straight, even though there’s a HUGE fluctuation in the outdoor temperatures during that time period? Believe me, even with a thermometer you would have no clue how to regulate the temperature from fluctuating even 10 -20 degrees Fahrenheit, day after day for up to 5 months straight!! How could it know the exact temperature that is needed for the optimal development of the chick? Who told it that 92 degrees is optimal? How does it know if it’s actually 92 degrees? Oh. I am glad you asked that. It is very clear that there’s built into these birds some biological apparatus that has the mechanism to send a VERY accurate temperature reading that registers in their brain. Scientist tell us that it’s either their beak, and or the tongue, (scientists still aren’t sure) of the mallee fowl that has the accurate temperature taking capabilities! How amazing is that?! Can an accident give it any of the above necessary knowledge? Can an accident make accurate thermometers in their mouth area? And if you think that perhaps they learned all this knowledge from their parents (which wouldn’t answer how the parents got that knowledge) that’s not possible, since, as we will see, that there’s absolutely no contact from the parents, to their chicks, at any point of time, once they hatch, period. Of course, we know the answers to all these questions. No, it’s NOT AN ACCIDENT! It’s all amazing instincts and “knowledge”, and a special temperature measuring apparatus, that Hashem has pre-programmed the Malle fowls brain, and placed it into these amazing birds.
Now, let us discuss the baby bird. Each hatched chick has to find its own way out of the mound to the surface. They may struggle anywhere from 2 to 15 hours, digging themselves out. They get no help from their parents, even though the egg shells are extremely thick and difficult to break out of, there’s no parental help AT ALL. Almost all other types of birds have a special egg “tooth” which helps them break out of their egg, but the Mallee fowl doesn’t have one. Nevertheless, eventually, they get out of their shells and make it out of the mound.
Finally, as soon as they get themselves out of the mound, they totter over to the nearest bushes to be in their shade where they rest for a day. Within 1 hour of hatching, the chicks can run and flutter. Within 24 hours of hatching, they can fly like an adult! The birds developed fully functional wings while developing in their egg! Most other birds hatch out of their eggs featherless, or close to featherless. Typically, other birds need to be under parental care for anywhere from 7-20 days and often for over 30 days, before they are ready to fully leave their parental care. The mallee baby birds have absolutely no contact with their parents. They are on their own as soon as they hatch. (It’s interesting how the Malle parent birds put in so much effort in bringing their eggs to their full development, yet they end up having nothing to do with the chicks at all. That’s the way Hashem set up their instincts. But don’t feel bad for them. There are no emotions involved, just pure instincts that Hashem put into them.
Of course, no one taught the chicks that as soon as they hatch, they need to dig their way out of the mound of rotting vegetation and soil. No one taught them which way was up, as opposed to digging themselves further down into the mound, assuring their death. How do they know that they must run to find shelter in the shade, in order to hide from predators, as soon as they get out of the mound? Oh, and how do they even know what a predator is, that it should want to escape from it? It has no training about this from its parents. Once again, the clear answer is that Hashem has pre-programmed all this knowledge into their instincts.
After all the eggs of that season have hatched, the parents rest for 1 to 2 months and then start the whole process all over again. The male Mallee Fowl may spend 10 to 11 months just taking care of the nest! It’s all in their instincts.
It’s interesting how we often see that Hashem, kaviyuchol, seems to like to have variety in His creatures. He seems to want to show us that He isn’t bound to any of His own laws of nature. Yes, 99.8% of birds incubate their eggs through their body warmth, and it is certainly much, much, easier to incubate eggs that way. Nevertheless, Hashem made these birds method of incubation (there are a few other birds in the Megapod family that are somewhat similar) using an entirely different method, having nothing to do with using the birds body warmth.
How amazing are Your wonders Hashem!
Below is a picture of an average mound, being prepared for egg placement.
The Mallee fowl’s incubation method is a testament to the wonders of Hashem’s creation. Rabbi Shmuel Waldman marvels at the intricate design and instinctual knowledge embedded in these birds, highlighting the divine planning behind their unique incubation process. He promises future articles to explore other fascinating creatures and their remarkable adaptations, further revealing the intricate and wondrous design of nature.