A cock bird is usually slightly larger than a hen (depending on the strain of bird). A male will spread it's tail feathers and drag them across the ground/floor when he is chasing after his female to go to nest. Females also spread their tail feathers, but they don't drag the feathers across the floor. Males make a distinctive "cooing" sound (more so than females). When eggs are present, males incubate during the day, females at night (they take 12-hour shifts). Males care for their squeakers once they leave the nest, while the female goes to nest again. Males tend to "defend" their perch space(s) more than females do (females just fly away). The top of a male's head is "flat" whereas a female's is rounded. Females just look more feminine than males do when looking at them as a whole.