If you mean literary devices or literary techniques, I would say alliteration is being used. Alliteration is basically the repetition of a consonant sound for poetic purposes. The words "cawing" and "creature" both feature the hard "C" sound, so this is definitely an example of alliteration.
I wish the phrase were a bit longer, or that you could include the rest of the sentence, so that I could see where the writer is going with this, but I suppose you could argue that he/she is using imagery, as well. Imagery is when a writer evokes the reader's senses by using detailed, descriptive writing about the way something/someone looks, sounds, smells etc. I don't know what creature the writer is discussing, but I can use the three words you've provided to assume that it looks "ugly," perhaps like some sort of a monster, since it is also called a "creature" as opposed to a human or specific animal, such as a bird. Also, I can tell that it is "cawing," which means it is making a loud, unpleasant crow-like sound. It seems like if the phrase were to continue, it may include more descriptive examples of imagery.