The avro is a creature that produces a distinctive-smelling feces. In August of 2380, reporter Ozla Graniv was briefly kidnapped by agents of the Orion Syndicate, and held in a basement in Downriver on Deneva which "smelled like avro dung." (ST novel: Articles of the Federation)

It is unclear whether the avro was an animal common on Deneva, or if the characterization of the odor was more figurative than literal.