Parrots That Eat Dirt

BrokenWing Chronicles
Parrots That Eat Dirt
Macaws eat clay from a riverbank in Peru. Scientists discovered why these birds have a taste for dirt.

Why do they do it?
In all the world there are just a few special places to see many colorful parrots in the wild. The most famous is at a bend of the Manu River in southern Peru, a small spot in the vast Amazon rain forest.

Early each morning a thousand or more parrots can be seen as they come to a bank of the river. These are the large chattery parrots also called macaws. Most of them are red and green, but there are other kinds with yellow and blue or scarlet feathers mixed in. Bird watchers come from all over the world to see the sight of those birds on display.

The idea of all those parrots coming together naturally leads to a question: what brings them? Just watching gives a surprising answer. They are eating dirt from the riverbank.

The Dirt They Eat
This is not just any old dirt. They carefully pick out a special layer that runs along the bank. By learning to recognize particular parrots, watchers can see that many come for their dirt breakfast almost every day.

We live in sheltered homes and eat carefully prepared foods. For most of us, the idea of eating dirt seems distasteful or, you could say, just plain dirty. But for wild animals it is common enough that there is even a special word for it: geophagy.

Dr. James Gilardi, a scientist studying the wild parrots, set out to find out why they were eating that special dirt. Were the parrots seeking soil minerals that were low in their foods? No, there were no needed minerals in the favorite soil that were not also in their foods.

Some birds use geophagy just to get grit (pebbles or coarse sand) to help their gizzards grind up food. But that didn’t fit the special soil layer the parrots were choosing. They liked a layer that was mostly smooth clay with tiny particles down to sizes of a millionth of an inch. So the parrots were not eating soil for its grit or minerals.

Dr. Gilardi kept at it until he did find an explanation for the parrots’ geophagy. The answer starts with an understanding of their other eating habits.

Parrots eat a lot of the fruit of forest trees. Fleshy fruits (think of peaches) are invitations to be eaten by animals. But the seeds inside are doubly protected. They are hard and tough. They also contain special chemicals called alkaloids that make them bitter or even poisonous if broken up.

Most animals chew up only the fleshy part of the fruit but pass the whole seeds into their feces. For the plants, that’s a great system. Their seeds are un-harmed, and the animals do them a great service by scattering their seeds.

A seed contains a little embryo plant all ready to grow. It also has a food storehouse with enough goody to get it started growing. By not chewing up those protected seeds, most animals are losing some very good food. But not parrots. They have hard bills and strong jaws that can crunch even the hardest seeds.

Parrots seem to have a special food source all to themselves. They can break the tough seed coats and chew up the seeds of forest trees. But there is that second part of the seeds’ defense. How do the parrots live with the poisonous alkaloids inside the seeds?

The Contents of Clay
Dr. Gilardi wondered if eating clay had something to do with that problem. He knew that naturally occurring clay has some special properties. It is made of small particles that carry a negative electric charge. Its particles can bind positively charged molecules, such as those of alkaloids. In a parrot’s stomach, even a small amount of clay might bind the alkaloids and keep them from being poisonous.

The Barraband's parrot also eats clay.

To test his idea Dr. Gilardi did a simple experiment. Eight captive parrots were fed pills of a mildly poisonous alkaloid called quinidine. Eight other parrots were fed the same pills together with a small measured spoonful of clay. Then blood samples from all the parrots were analyzed to see how much of the quinidine was taken into the parrots’ bodies.

The answer was clear. The birds that were also given clay took up only about one-third as much quinidine. Eating clay is the parrots’ way of living with the alkaloids of seeds.

Amazonian parrots have been getting special attention because they are decreasing in numbers. Many are being captured by native peoples to be sold as pets.

If it were not for the endangering effects of people, the parrots of the Amazon would have it made. They have a favorite and almost private food source in the fleshy fruits and seeds of forest trees. To prevent stomachache from the alkaloid poisons of the seeds, all they need is a breakfast of clay once a day from a riverbank.

BrokenWing Comment,
Parrots in the wild, eat some strange things, there hunger demands this, so how do they survive?
Why, why do they not suffer many of the diseases and viruses as the Caged Parrots seem to endure?
How do they know what to eat to balance there system?
The Hyacinth Macaw will follow a cow and dig nuts from the cows droppings, why then does the bird not become ill by doing so?
The Amazon parrot, even the little Cockatiel will eat the flesh of dead animals, not fresh meat, by all means (un healthy un cooked meat) and the female Amazon actually demands raw meat during breeding and will attack small rodents to fill such a thirst for protien.
All birds know of survival, they know what they need to do to stay alive, in humans, this is called reasoning, the ability to think and come up with an answer.