Rice fields as a feeding habitat for waders in inland south-east Australia

Irrigated rice fields occupy an average area of 110,000 ha annually in Australia, mainly in the  catchments of the Murrumbidgee, Lachlan and Murray Rivers. Water abstraction for this and other forms of irrigated agriculture has greatly reduced the area of natural inland wetlands throughout the Murray–Darling Basin since the 1960s. Inland wetlands are important habitats for large numbers of resident and migratory waders. We assessed the significance of rice fields as an alternative habitat for waders in an area around Fivebough Swamp, southern New South Wales. Rice fields were used regularly by five species for feeding and only during the first four to six weeks following initial flooding of the fields in spring (October and November). Thereafter, increasing water depths in the fields as the crops grew precluded their use by waders. Densities of birds were highest in organically grown crops in which the lack of pesticide application was associated with substantially higher densities of aquatic invertebrates than in conventional crops. By comparison, eight species fed regularly on Fivebough Swamp, a natural seasonally temporary wetland between July and January, about five months longer than in rice fields. The mean densities of waders on rice fields were extremely low compared to those on the natural wetland. There was no evidence that any waders attempted to breed in or around rice fields whereas three species bred on the wetland. It is concluded that rice fields are not an adequate alternative  habitat and do not substitute for the loss of natural wetlands.