What factor is most responsible for giving the Emperor Goose an 'endemic specialist' designation despite current population numbers?

Answer

The tight geographic concentration of their nesting grounds on remote tundra

The species is considered an endemic specialist because the entire known population nests in a geographically restricted area covering only a few thousand square miles of remote tundra, making them highly concentrated.

What factor is most responsible for giving the Emperor Goose an 'endemic specialist' designation despite current population numbers?
raritybirdEmperor Goose