This is bird note.

When birds swallow berries,

when birds swallow berries, they also ingest the seeds within the pulp.

After just half an hour or so, they dispose of the seed by passing it through their digestive system or regurgitating it. Either way, the hard seeds wind up on the ground.

There's an evolutionary reason for this. Plants that evolved fruits with edible flesh could attract

birds to eat them. Then the birds transport the hard seeds within the soft

fruits to new spots for them to take root.

But birds do more than just carry the seeds.

Their digestive system includes but birds do more than just carry the seeds.

Their digestive system, including their muscular gizzard,

grinds away the hard outer coating on seeds,

making them more likely to germinate

once the birds deposit them.

What's more, seeds in a bird's droppings are prepackaged

in nutrient-rich fertilizer when they hit the soil.

Birds disperse seeds for more than 300 trees, bushes and vines in North America.

The benefits are mutual.

A fruit-eating bird sows more fruit-bearing plants,

leading to more fruit for birds to reap in the future.

It's a relationship developed over millennia of co-evolution.

For Bird Note, I'm Michael Stein. I'm Michael Stein.