When Cole finally found the baby birds, what had happened to them?

He found them lying in the grass with their mouths open.

"And then he saw them.

First one, then two, then a third and fourth—four lifeless baby sparrows, scattered in the short grass where they had been thrown from their nest. Matted fuzz covered the twisted little bodies. Two had died with their big yellow beaks open as if searching for food. The other two lay facing the nest, their necks reaching out. Even in death, the sparrows had strained toward their nest. They had tried to make it back to the safety of their home."