At about 2-feet, the mallard is your “classic” duck. Adult males have shiny green heads with yellow bills and females are mottled brown with orange bills tipped in black, both with orange feet. Wild mallards are uncommon winter visitors that usually don’t show breeding feathers. Most mallards in Hawaiʻi are descendants from imported domestic stock from the 1800s. This species interbreeds often with the native endangered koloa and, so, threatens the uniqueness of the species through hybridization.