Habitat use by Least Bitterns in the Arkansas Delta

Least Bittern (Ixobrychus exilis) occupancy surveys were conducted in the Arkansas Delta, USA, during April-July 2005-2006 to determine the proportion of area occupied and relate occupancy to habitat characteristics. Previous large-scale surveys indicated few Least Bitterns were present in the Delta. During surveys at 190 sites, Least Bitterns were detected at 15 sites in 2005 and at 16 sites in 2006. Several candidate models were tested to explain occupancy based on habitat variables. Emergent vegetation cover was positively related to occupancy while the proportion of forest within 400 m of a survey site was negatively related to occupancy. The study suggests that managing the breeding habitat of Least Bitterns for emergent vegetation cover and controlling forest cover near occupied sites may contribute to this species' recovery throughout its range.