Assessing conservation trade-offs: identifying the effects of flooding rice fields for waterbirds on non-target bird species

I examined how winter flooding of post-harvest rice fields—a management practice used to benefit waterbirds—affects field use by other birds. In addition to waterbirds previously studied, I recorded 56 bird species in rice fields. Of these, five were more abundant in flooded fields, ten were more abundant in unflooded fields, no difference was detected for 19, and the remainder were too rare to draw any conclusions. Species that were more common in unflooded fields were all carnivorous or granivorous in winter, whereas species that were more common in flooded fields were mostly insectivores commonly associated with aquatic habitats. The net effects of the responses by individual species were fewer raptor species in flooded fields, but no difference in the species richness of other landbirds. Winter flooding potentially has negative effects for some birds, but has no discernible effects on most species studied and may benefit some passerines.