Mom looks for a nest.

Mom sees a nest.

It is a reed warbler nest.

There are three eggs inside.

Mom lays her egg next to the other eggs.

Then she leaves it there and flies away.

The reed warblers sit on the nest.

The eggs look the same.

The cuckoo hatches first.

The reed warbler thinks he is her baby.

She goes to get him food.

The baby gets to work.

He pushes the other eggs out of the nest.

They fall to the ground.

There are no more eggs.

The mom comes back.

She feeds the cuckoo baby every day.

He grows big very fast.

He is bigger than a reed warbler.

He is a cuckoo.