The common name "hardhead" has nothing to do with the density of the bird's skull, instead referring to the difficulty encountered by early taxidermists in processing the head.

[2] Hardheads are found in wetter, coastal regions of Australia, particularly in the south-east, but are known to disperse as far afield as New Guinea, New Zealand, and the Pacific Islands.

Significant numbers reach as far afield as New Guinea, New Zealand, and the islands of the Pacific, where they can remain for some time, even breeding for a season or two.

[3] Hardheads prefer larger lakes, swamps and rivers with deep, still water, but are often seen in smaller streams, flooded grasslands, and shallow pools.

[1] Like the other members of the pochard group, hardheads feed by diving deeply, often staying submerged for as long as a minute at a time.