The way the sentence was formed 'Dropped in the bushes, the child found the missing keys' implies that the <em>child</em> was dropped in the bushes, because there is a misplaced modifier. The correct meaning (<em>the missing keys</em><em> were</em> <em>dropped in the bushes</em>) is easier to perceive by rewriting the sentence: "The child found the missing keys dropped in the bushes."
