He wanted just one crow's egg, and he had a theory that birds cannot count.

He liked crows--in fact, on that farm no one was ever allowed to shoot crows or any other birds except the murderous duck hawk, and he felt that the crows owed him _one_ egg, anyhow, in return for the protection they enjoyed on his father's property.
"Now, you must not think he chose the pine tree because it was the easiest to climb," went on Uncle Andy hurriedly, seeing in the Babe's eyes that this point had to be cleared up at once.

"In fact, it was the _hardest_ to climb.

Any one of the fir trees would have been easier, and they all had crows' nests in them.

But the boy knew that he could not climb any of them without getting his clothes all over balsam, which would mean a lot of inconvenient explanations with his mother.