Correlation between female egg cooling and male individual behavior around nest of captive black curassow during incubation

Black Curassow (Crax alector) is a typical ground-dwelling bird within Cracidae. Currently, studies on reproductive ecology of Black Curassow remain absent, captive populations face multiple challenges including natural breeding difficulties and low hatching rates. In this study we systematically recorded for the first time reproductive and individual behaviors of a pair of captive Black Curassows during the incubation period, and analyzed time allocation of parental behaviors and differences between the sexes. Parental birds exhibited a significant sexual dimorphism in their incubation behavior, with females sharing an averaged 90.78% of the total incubation duties, while males being responsible for protecting the eggs in the absence of the female and for some egg turning. The behaviors of males, such as wandering around the nest box and preening near the nest, were significantly positively correlated with the cooling behavior of females (Spearman, r = 0.972, P < 0.0001, n = 26), indicating highly synchronized peri-nest activity of males with female egg cooling behavior. This study documents behavioral division of labor and cooperative characteristics between male and female captive Black Curassow during incubation. The findings not only fill the research gap in the reproductive ethology of Black Curassow but also demonstrate that under captive conditions, the role of male during incubation must be given full consideration to optimize husbandry protocols and enhance hatching success.