The sentence "He clasps the crag with crooked hands" employs a figure of speech called personification. Personification is when an author gives a non-human thing - an object, an idea, an animal - attributes or features of a human. In this case, the pronoun "he" is being used to refer to an animal even though the correct pronoun would be "it". Also, the author chooses to use the word "hands" - a human body part - to refer to the eagle's "claws".