How do you tell if a loon is a male or female?

In loons, distinguishing between males and females can be challenging since they look quite similar. However, males are generally larger than females and have slightly more vibrant plumage, especially during the breeding season. Additionally, males often possess a deeper and more resonant call compared to the higher-pitched calls of females. Observing their behavior, particularly during mating rituals, can also provide clues to their gender.