Louisiana black-bellied whistling-duck clutch characteristics in the presence of conspecific and interspecific brood parasitism

Black-bellied Whistling-Ducks (Dendrocygna autumnalis; hereafter Whistling-Duck) are undergoing a rapid range expansion northward and now breed throughout the southeastern United States. As a facultative cavity-nesting species, they have the potential to compete with Wood Ducks (Aix sponsa) and Hooded Mergansers (Lophodytes cucullatus) for nest sites. Little is known about Whistling-Duck breeding biology, and estimates of clutch characteristics and rates of conspecific and interspecific brood parasitism (hereafter, CBP and IBP respectively) are lacking. We monitored Whistling-Duck nests in Louisiana to describe nesting chronology, clutch size of parasitized and unparasitized (hereafter, normal) nests, and hatchability (i.e., the portion of eggs that hatched) for clutches of different sizes and types. We monitored a total of 558 nest boxes 2020–2021 and determined the presence of brood parasitism for 231 Whistling-Duck nests. CBP was detected in 73 (31.6%) nests, and IBP was observed in ..., ,