The blue duck (Hymenolaimus malacorhynchos) is one of the most famous birds in New Zealand and is even illustrated on the $10 dollar note. Furthermore, the species has a significant cultural value for certain Maori tribes. They are endemic to New Zealand and considered to be nationally vulnerable.
Blue ducks grow to around 50 cm in length, and adult males may weigh up to 1 kg. They are characterised by a rather brown chest leading to a lighter grey plumage for the rest of the body. In addition, blue ducks have bright yellow eyes, and a black tip on their bill that looks like the bird just dipped the tip in black ink. Blue ducks prefer clear streams and riverbeds of higher altitudes as habitat and spend their life in territorial pairs. They primarily feed on invertebrates found in and around those waters. Males and females only differ slightly. Males are usually larger than their partner and their chest has a bigger area of the typical, light-brownish colour.
Today, this species is still present in parts of the North as well as the South Island. However, experts estimate the current population to vary between 2000 and 3000 individuals. Blue ducks are threatened through a loss of habitat and increasing water tourism. Another major threat, introduced predators - such as stoats and possums - have significant impacts on many endemic birds in New Zealand.