H e was investigating Yellow-naped Amazons there. The majority of males had five red feathers in the speculum, the females had four. Then he checked the male. Only four red feathers in the speculum, and perhaps the reason he was unable to attract a mate. Paraguay, Blue-fronteds males had more red feathers in the speculum than females.
Females often flatten themselves like ducks.
Females sit with feet further apart than males, probably because of the position of the hip bones. Females more likely to bite. Males tend to be louder. Females more likely to go to the floor of the cage. Low and Hagen say be sure with surgical sexing O thers have stated that the males beaks and heads can be larger than females in the species, and Rosemary Low says males look bolder.