We conducted 11 call-broadcast surveys at one location in each of four wetlands, and detected an Ixobrychus exilis (Least Bittern) on only 9 of the 44 (20%) surveys, while the observer was located on average 50.1 m ± 19.7 SD (range = 25–75 m, n = 11 nests) from at least one active bittern nest during each survey. For 8 of 9 (89%) detections, at least one bittern was already vocalizing at the beginning of the survey, before the Least Bittern call was played. We show that it is possible for this species to remain undetected with the use of call-broadcasts that are less than 30 seconds, even though the species may be nesting as close as 25 m to the location from which the calls are broadcasted. We suggest that systematic nest searches are more reliable than call-broadcast surveys for detecting nesting Least Bitterns.