Australasian Shovelers (Anas Rhynchotis) have traditionally been divided into two subspecies, but because ducks banded in Australia have been recovered in New Zealand. Flying swiftly on whirring wings, the shovelers often fly quite high, and may turn abruptly in flight. Commonly the shoveler gathers in small groups within large flocks of other ducks. Probably due to the consumption of large quantities of invertebrate they have an offensive smell when cooked. They often forage away from cover in shallow or deep, open water, heavily vegetated swamps are preferable to open lakes. The Australasian Shovelers (Anas Rhynchotis) dwell on a variety of wetlands, including irrigated fields, reservoirs, sewage ponds and farm dams. Courtship in Australasian Shoveler (Anas Rhynchotis) starts around August which involves vocalizations from the male accompanied with head-bobbing whilst swimming toward the female. The most heard vocalizations are from the drakes in the form of a "Sock, sock-sock, sock, sock-sock". Generally the mated males are aggressive and will not tolerate this behavior from the bachelors. Courtship flights are common in the morning and evenings mostly, where the duck is followed in a short rapid flight by one or more (usually two) drakes. The duck will even sometimes excrete mid-flight on a perusing male if he is especially not to her fancy. There is a clear and unexplained sex ratio difference with a lot more males to females. This difference is not present in broods of ducklings however. Males with a lot of white breast feathers are not usually paired. These white feathers are often a sign of an older Shoveler as first year males almost never have them. Mating will occur as early as August, though nesting rarely happens until at least October. The nests are normally located amid concealing thick or scarce vegetation near water. Females also very rarely nest in hollow stumps, and exceptionally even in hollow trees. Incubating birds flush only reluctantly and must rarely be stepped on to drive them off nests.