The difference between a statue and sculpture is if the piece is modeled after an actual person, thing, or animal or is conceptual. Furthermore, unless cast from a mold created from an object - statues ARE sculptures. There's no way to know if the artist modeled the piece after actual birds or if it's conceptual. I can be certain, however, that fertilization doesn't look anything like what you're getting hot and bothered over.
I have somewhere around 500 birds as part of a second business of mine.