Dirt-Eating Parrots

music
ambience: Macaws

Parrots in many parts of the world have a rather unusual dietary habit. They eat clay, and it just may be keeping them alive. I’m Jim Metzner, and this is the Pulse of the Planet. James Gilardi is research director of the Oceanic Society, and he studies parrots in the Amazon, such as these macaws that we’re listening to right now.

“Most of the obvious places we see them eating soil are along large rivers in the southeastern corner of Peru. A lot of birds come down to the ground to eat grit and large particles of hard material which helps them grind up their food. And so for a long time people assumed that if you saw a parrot on the ground, that that’s what it was doing. The soils that they’re eating in Peru are extremely fine-grained soils. They have a very high proportion of clay, which is a very smooth particle size. And so it’s pretty clear that at least the parrots that we’ve been studying are not consuming the soil for its ability to grind things up in the gizzard.”

On any given day, a parrot may eat as much as ten percent of its body weight in soil. The rest of its diet is composed of fruit and seeds. And some of the seeds contain toxins.

“Now what the parrots seem to be able to do is get into those seeds, cracking them open, getting the kernel out, and then they’re, for some reason, able to digest these really toxic substances without causing them problems. Now, by looking at what the clays are capable of doing, say, in a test tube, it’s suggested to us that maybe one of the reasons they’re eating the clay is to detoxify these foods that they’re eating. So we looked at the types of clay present, and tested those clays and it turns out that these are the right kinds of clays.”

So scientists think that eating clay lets parrots digest seeds that might otherwise kill them. Pulse of the Planet is presented with support provided by the National Science Foundation. I’m Jim Metzner.

music

Dirt-Eating Parrots

Some parrots have an unusual dietary habit that may be keeping them alive --they eat clay.
Air Date:09/27/2000
Scientist:
Transcript:


music
ambience: Macaws

Parrots in many parts of the world have a rather unusual dietary habit. They eat clay, and it just may be keeping them alive. I'm Jim Metzner, and this is the Pulse of the Planet. James Gilardi is research director of the Oceanic Society, and he studies parrots in the Amazon, such as these macaws that we're listening to right now.

"Most of the obvious places we see them eating soil are along large rivers in the southeastern corner of Peru. A lot of birds come down to the ground to eat grit and large particles of hard material which helps them grind up their food. And so for a long time people assumed that if you saw a parrot on the ground, that that's what it was doing. The soils that they're eating in Peru are extremely fine-grained soils. They have a very high proportion of clay, which is a very smooth particle size. And so it's pretty clear that at least the parrots that we've been studying are not consuming the soil for its ability to grind things up in the gizzard."

On any given day, a parrot may eat as much as ten percent of its body weight in soil. The rest of its diet is composed of fruit and seeds. And some of the seeds contain toxins.

"Now what the parrots seem to be able to do is get into those seeds, cracking them open, getting the kernel out, and then they're, for some reason, able to digest these really toxic substances without causing them problems. Now, by looking at what the clays are capable of doing, say, in a test tube, it's suggested to us that maybe one of the reasons they're eating the clay is to detoxify these foods that they're eating. So we looked at the types of clay present, and tested those clays and it turns out that these are the right kinds of clays."

So scientists think that eating clay lets parrots digest seeds that might otherwise kill them. Pulse of the Planet is presented with support provided by the National Science Foundation. I'm Jim Metzner.

music