North American waterfowl are often divided into five categories:

• Dabbling ducks - These ducks feed by tipping down to reach aquatic plants and invertebrates below the surface. Dabbling ducks spring into the air to take flight.
• Diving ducks - These ducks dive and swim underwater to locate their prey. To take flight, diving ducks need a running start across the water.
• Sea ducks - Sea ducks are essentially diving ducks, but sea ducks spend a portion of their life in marine or estuarine habitats.
• Swans and geese - Swans and geese are the largest members of the duck family (Anatidae).
• Whistling ducks -These ducks are also known as tree ducks and include species such as the Black-bellied Whistling-Duck and Fulvous Whistling-Duck.

Over 40 species of waterfowl have been documented in Maryland. To assist with identification of these species, please check out the following resources:

• Cornell Lab of Ornithology
• Ducks.org - Waterfowl identification for hunting
• Ducks at a distance - a waterfowl identification guide
• Flyways.us - Waterfowl ID - a guide to identifying North American waterfowl
• Keys to Aid Hunters in Identification of Live Decoys
• United States Fish and Wildlife Service - species, age, and identification of ducks using wing plumage