The Bald Eagle (Haliaeetus leucocephalus) is North America’s largest true bird of prey and a majestic apex predator. Its diet is highly specialized but also marked by a remarkable degree of opportunism. The eagle’s feeding habits reflect its powerful physical capabilities and its ability to adapt to diverse environments. Its survival strategy relies on flexibility in food acquisition.
Fish: The Dietary Cornerstone
Fish constitute the majority of the bald eagle’s diet, often making up 60% to 90% of its food intake, which explains why they are almost always found near large bodies of water. The eagle possesses specific physiological adaptations that make it an efficient fisher. Its powerful talons are deeply curved and sharp, designed to pierce and hold slippery prey.
A unique feature aiding in fish capture is the presence of spicules, which are rough, sharp projections on the pads of the eagle’s toes that provide a superior grip on fish scales. Eagles prefer to target fish swimming close to the surface, such as salmon, herring, trout, or catfish, allowing them to snatch the prey without fully submerging. They often focus on sick, injured, or dead fish that are easier to catch than healthy, fast-moving ones, a form of specialized scavenging.
Other Live Prey Items
When fish are less available, bald eagles actively hunt a variety of other live vertebrates, which can account for a significant portion of their diet. Waterfowl are a common secondary food source, especially during winter months when lakes and rivers freeze over. Eagles pursue birds like ducks, coots, and geese, often targeting weakened or vulnerable individuals.
They also prey upon small mammals, including rabbits, squirrels, muskrats, and various rodents. These terrestrial hunts generally occur when eagles are near their nests or forced inland away from fishing grounds. Less frequently, they will take reptiles and amphibians, such as water snakes and turtles, particularly in warmer regions. This demonstrates the eagle’s capacity to switch from a specialized fisher to a more generalist predator based on immediate need.
Opportunistic Feeding Behaviors
The bald eagle is an opportunistic feeder, readily exploiting non-hunting methods to acquire sustenance and conserve energy. One major behavior is scavenging, or eating carrion, which is important during periods of scarcity. Eagles consume dead animals ranging from washed-up marine mammals and fish to the carcasses of large ungulates like deer.
Scavenging is crucial in winter when ice covers waterways and fish are inaccessible, or for immature eagles still honing their hunting skills. Another notable feeding tactic is kleptoparasitism, the practice of stealing food that another animal has already caught. Eagles harass other raptors, particularly ospreys, until the smaller bird drops its catch, which the eagle then retrieves. This is a highly effective, low-effort method of obtaining a meal.
Geographic and Seasonal Diet Variations
The specific composition of the bald eagle’s diet is highly dynamic, shifting significantly based on both geographic location and the time of year. Regional differences dictate the type of fish and other prey that are most available. Coastal populations often rely on marine species and seabirds, while eagles inland focus on freshwater fish like bass and pike. In specific areas like the Pacific Northwest, the massive runs of salmon during the late summer and fall become the dominant food source for local eagle populations.
Seasonal changes also drive dietary shifts, especially in northern latitudes. During the breeding season, the diet heavily favors live fish to feed the young. When winter causes water bodies to freeze, eagles migrate or switch to more readily available food. This forces a greater reliance on scavenging carrion or hunting vulnerable waterfowl concentrated in the few remaining patches of open water.