Continuity mistake: Kong breaks the window and takes Ann from bed. In the wide shot (where she's replaced by a stop-motion doll) she faints backwards. In the immediate close-up she is conscious and upright.
Continuity mistake: After Kong escapes from the theater, a car crashes against a wall with no glass on the windshield. In the next shot, broken glass appears.
Continuity mistake: This happens in King Kong's death scene. After he puts down Ann for the last time, he is shot and his right arm goes limp. In the close-up, he's suddenly using that limp arm to hold on to a spire.
Continuity mistake: During King Kong's rampage on the island, he fights some of the natives on a scaffold platform. He picks up one of them and puts him in his mouth. In the wide shot, the native's feet are on the left side of Kong's mouth and his head is on the right. The close-up shows that his head is on the left while his feet are on the right.
Answer: It's never shown or explained, and the film uses a broad "suspension of disbelief" premise. The audience just accepts the characters were able to somehow transport a huge ape to New York City.
raywest ★