I’d just like to interject for a moment. What you’re refering to as a Gull, is in fact, Sea/Gull, or as I’ve recently taken to calling it, Sea plus Gull. Gull is not an categorization unto itself, but rather another component of a full identity made useful by the kingdom, phylum, class, order, family, genus, and species components comprising a full identification as defined by its scientific classification.