Snake slough in nests of crested mynas: effect on breeding success and nestling growth

The choice of suitable nest materials is a key to nest-building process in birds. During the breeding season (March-August) in 2018 and 2019, we discovered that crested mynas (Acridotheres cristatellus) added snake slough (2–18.3 cm in length) to their nests. The addition of snake slough continued throughout the breeding period, with a proportion of 38.9% being during the nest-building period. The use of snake slough in 2018 (38.5%) was significantly less than in 2019 (71.4%). No significant differences were found in clutch size, egg mass, and egg size between nests with snake slough (the slough group) and nests without snake slough (the non-slough group). There were also no significant differences in the number of nestlings hatched for each nest, nestling growing and breeding success between the snake slough and the non-snake slough group. This is the first study to report that crested mynas add snake slough to their nests throughout their breeding period, but snake slough had little impact on most of the breeding parameters of crested mynas. We speculate that snake slough in crested myna nests may serve to reduce nest predation, improve the immunity of nestlings or serve as a post-mating sexual signal eliciting differential reproductive investment in mates; however, these speculations require further investigation.