Ixobrychus is a genus of bitterns, a group of wading bird in the heron family Ardeidae. It has a single representative species in each of North America, South America, Eurasia and Australasia. The tropical species are largely resident, but the two northern species are partially migratory, with many birds moving south to warmer areas in winter.The Ixobrychus bitterns are all small species, their four larger relatives being in the genus Botaurus.