Instructions
Look at the weight difference between a breeding pair of sandhill cranes. Females average 9-1/2 lbs.; males are around 12 lbs.
Listen to the cranes calling to one another. The male makes a low-pitched call and the female makes a high-pitched one.
Watch a male and female during their mating dance. The male sandhill crane throws its head up so that its neck makes a vertical line; the female throws its head up at only a 45-degree angle from its usual (horizontal) position.