In 2008 the first egg of a clutch of six was laid on 8 April. The nest was not checked in a later stage, but several weeks later two fledglings were observed. On 12 June the young of a second attempt were on the verge of fledging (picture). In 2009 at the same location the first egg was laid on 15 April. Clutch size was probably five (number of small chicks). On 14 May the young were fledged. A second attempt resulted in a clutch of six on 29 May. On 7 June this nest contained six small chicks. On 15 June the nest was empty and probably predated. A second pair occupied an especially erected nest box at the wall of another sluice. The nest contained a fresh clutch of 5 eggs on 19 April. At later checks the young appeared to have the same age as the young of the first pair. On 14 May the nest was empty, but nearby alarming parents suggested that the young fledged successfully. On 29 May the female incubated a second clutch of five eggs. On 15 June the nest contained five large young and on 19 June the nest was empty. Probably the young left the nest successfully. On 27 July the pair attempted to build a third nest in a too small space in the sluice wall. The nest was not finished