Whio are strong swimmers and capable divers and live in clean, fast-flowing rivers in the North and South Islands of New Zealand.
Their fleshy edged bill is perfect for collecting insects, grubs and caddis fly larvae around boulders in the rapids.
Males make a distinct whistling call (hence the Māori name 'whio') while females sound more like a rattle.
Perfectly camouflaged in their habitat - their blue/grey colour makes them look just like a rock.
Every healthy duck hatched at the Zoo is part of a coordinated breed and release programme. With less than 3,000 whio left in the wild, each duckling makes a big difference!