The common loon is a water bird that has a scientific order all to itself. Found throughout North America, it lives as far north as Alaska in the summer and travels south to the Gulf of Mexico in the winter. The state bird of Minnesota, it has distinctive coloring and an unmistakable call.
Adults have an average size of anywhere between 28 and 36 inches (about 71 to 91 cm) long. Their wingspan can be up to 5 feet (1.5 m), and with their wild, laughing summer call, they are often heard before they are seen. The male and the female common loon have similar coloring; in the summer, they have black heads, black and white checkered backs, and a white collar around their necks. Colors become more muted in the winter months, when they head south. Immature birds retain this muted color year-round until they reach maturity, and hatchlings are covered with fuzzy, black, downy feathers.
The common loon is a carnivore, and feeds largely on small fish, amphibians, and insects. Ungainly on land, it is an expert swimmer and diver; some have been recorded making dives as deep as 200 feet (about 60 m) while chasing prey. In turn, the common loon can find itself prey to large sea birds and fish, and may be caught and killed by land animals like raccoons, especially while nesting and defending its young.
The birds' main habitats are on freshwater lakes, and they can withstand even the cold water temperatures found on the tundra of Canada. Spending their summer months in the north, they migrate south when the weather cools; once there, they molt and are grounded until their fresh set of feathers returns. Hunting in the water throughout the year, they go to land to breed and lay their eggs in ground nests.
Pairs of common loons have between two and four eggs in a breeding season. Hatchlings can walk within a day of emerging from their olive and brown camouflaged eggs, and while they are unable to fly until they are about 11 weeks old, they can often be seen riding on their parents' backs as the adult birds swim. While nesting and protecting its young, the common loon can be ferociously aggressive.
Flocks of birds can suffer from pollution in the lakes they rely on for habitats and food. Eating fish that have been poisoned by runoff or pesticides can kill birds, and a loss of shoreline nesting sites have also had a measurable, negative impact on the numbers of birds in the wild. Intrusion by humans and animals on nesting sites can cause adult birds to abandon their nests and leave the eggs unhatched.