The role of artificial habitats and rainfall patterns in the unseasonal nesting of Sarus Cranes (Antigone antigone) in south Asia

Sarus Cranes (Antigone antigone) in south Asia breed during the rainy season (monsoon), with fewnests initiated outside of the monsoon. Several hypothesis have been put forth to explain the unseasonal nestingoutside the monsoon, but a careful evaluation of the hypotheses has been absent. Using a multi-year (2004-2017),multi-scale (four Indian states) data set, this study explored the factors potentially responsible for unseasonal nestingby Sarus Cranes. Nests outside the monsoon were very rare (0.3% of all nests) and were initiated when SarusCrane pairs were in areas with artificial water sources (irrigation canals or reservoirs) or faced abnormal monsoonalconditions. Unseasonal nests were initiated only when breeding pairs had been unsuccessful in raising chicks inthe previous primary nesting season. Altered cropping patterns associated with increased artificial irrigation andchanging rainfall patterns appear responsible for unseasonal nesting in Sarus Cranes. Nesting of this species outsidethe monsoon may increase in response to the increasing changes in cropping patterns and changing rainfallconditions.