Fantastic whio feathers

The blue duck/whio is endemic to New Zealand. It has some unique adaptations that allow it to survive in its specific habitat. These features include a special soft bill for scraping insect larvae off the rocks, excellent camouflage and a streamlined body. The whio, along with all duck species, also has different types of feathers, each with specific qualities. As whio live in very cold, fast-flowing water, the insulating and waterproofing properties of their feathers are very important.

Ducks have three main types of feathers: flight, contour and down feathers. Each type of feather provides a different function.

Flight feathers are long and strong and are precisely aligned with the help of tiny barbs that hook together to form the vane of the feather. This is the flat soft part on both sides of the central shaft. The barbs also hold the feathers securely in place during flight.

Contour feathers provide the bird’s shape and colour. They also have barbs, holding them in place, overlapping each other much like tiles on a roof. This helps to create a waterproof coat with air pockets trapped underneath for buoyancy and warmth.

Down feathers are fluffy and soft for warmth and have no barbs. They are found underneath, growing between the other feathers.

Preening

Preening is an important behavioural adaptation for whio. A gland on the bird’s tail releases waterproofing oils, and preening spreads this oil over the feathers. Often birds can be seen preening after getting wet. Department of Conservation rangers say preening is the most common behavioural observation of whio.

Moulting

When the breeding season has finished and chicks have fledged, adult whio moult. Moulting involves the ducks losing their feathers and replacing them with new ones. Whio are particularly vulnerable to predators at this time of year because they cannot fly. They tend to hide away in small side streams or caves, only coming out to feed at sunrise or sunset.