Looking it up, "Sula" is indeed a genus of seabirds commonly known as gulls or boobies, but "Miranda" as a species name... Hmm, I don't see a bird named Sula Miranda. Maybe it's a misspelling. There's a Sula sula, also known as the Brown Booby, but that's the binomial name. Miranda isn't part of the scientific name for that bird. Alternatively, could it be a local common name in Portuguese? Maybe "Sula Miranda" is used in some region to refer to a specific bird.