Female and male Common Loons look identical in plumage, making them impossible to tell apart visually by an untrained eye. Males are generally about 25% larger than females, but this size difference is only obvious when the two birds are swimming side-by-side. Females construct the nest out of mud, moss, and aquatic vegetation very close to the water’s edge. They typically lay one to three olive-brown eggs with dark spots. 🕊️✨