a mallard, but its call is softer and it quacks less frequently. Behavior The Hawaiian duck is a very wary bird, often found in pairs instead of large groups. The koloa is most prominently found residing in the tall, wetland grasses and streams near the Kohala volcano on the main island of Hawai’i (Reed et al. 2012). They are very secretive birds and do not associate with other animals much. Reproduction Some pairs nest year-round, but the primary breeding season is from December to May, during which pairs often engage in spectacular nuptial flights. The clutch size is usually eight. The female lays two to ten eggs in a well-concealed nest lined with down and breast feathers. Incubation lasts about four weeks. The young can take to the water soon after hatching, but cannot fly until about nine weeks of age. Offspring become sexually mature enough to reproduce after a year. Female Hawaiian ducks have a strange attraction to male mallards (a more general species of ducks in the same area). It's unknown whether the female Hawaiian duck attracts the male mallard or whether the color variation of the male mallard attracts the female. In any case this interbreeding creates viable offspring.[7] Evolution has not moved fast enough for this species to be unable to mate. This interbreeding is one of the main causes for the endangerment of the Hawaiian duck, specifically hybridization, which is explained below.[7] Location and environment The former range of the Hawaiian duck included all of the main Hawaiian islands except the islands of Lānaʻi and Kauaʻi. Hawaiian ducks were found on the hottest coasts with suitable ponds as well as in the mountains that were up to 7,000 feet high.(Perkins 1903, cited in Banko 1987b). This includes low wetlands, river valleys, and streams in mountains. “Genetically-pure Koloa populations were believed to occur on the islands of Kaua'i (Browne et al. 1993, Rhymer 2001), Ni'ihau, and highlands of Hawai'i with hybrid swarms on O'ahu and Maui (Engilis and Pratt 1993), but there is now evidence of hybridization within pure populations (Engilis et al. 2002).” The Hawaiian duck was extirpated on all other islands, but was subsequently reestablished on Oʻahu, Hawaiʻi, and Maui through release of captive-reared birds. However, all the Hawaiian ducks in the reestablished populations have bred with feral mallard ducks and have produced hybrid offspring that are fully fertile (Griffin et al. 1989); consequently,