Nannopterum auritum, commonly known as the double-crested cormorant, is native to North America. Its range extends across the continent, from the Aleutian Islands in Alaska, through Canada, to the coastal and inland regions of the United States and as far south as Mexico and the Bahamas.

Double-crested cormorants are typically found in aquatic habitats including rivers, lakes, and coastal marine environments. They prefer freshwater and saline ecosystems and are often seen on rocky outcrops, trees, or other structures near water bodies. The species thrives in temperate to tropical climates, demonstrating a high level of adaptability to various water-based environments.

As piscivorous birds, double-crested cormorants primarily feed on fish, diving to capture their prey with strong, webbed feet. They play a role in controlling fish populations and are often considered indicators of ecologically healthy aquatic systems. Their ecological niche also involves habitat creation for other species through their nesting activities, often leading to interactions with other bird species.