Which birds are native and why that is important is not a simple as many think.
It's an argument Whanganui Regional Museum Curator of Natural History Dr Mike Dickison will make in a public lecture next week.
New Zealand distinguishes between native birds, which are legally protected and often under threat, and introduced birds, which have almost no legal protection and often hunted or eradicated.
But this distinction doesn't match with archaeological and fossil records.
Some of New Zealand's birds are self-introduced, some arrived after Polynesians but before Pākehā, and others have ancient roots.