Eagles are large birds of prey belonging to the family Accipitridae. These formidable hunters are situated at the top of their food chains, acting as apex predators in the environments they inhabit. An eagle’s diet is highly varied and opportunistic, depending greatly on its geographical location and the type of prey that is most readily available. This adaptability means that while one species may focus almost exclusively on fish, another may subsist primarily on mammals or reptiles.
Primary Prey Categories
The diet of eagles is broadly categorized into several main classes of vertebrates. The Haliaeetus and Icthyophaga genera, commonly known as sea and fish eagles, rely heavily on aquatic life. Their primary food source is fish, which they snatch from the water’s surface, including species like salmon, trout, herring, and catfish. These aquatic hunters also consume other water-dwelling creatures such as amphibians, turtles, and crabs as supplementary meals.
Many eagles, particularly those inhabiting open country and mountainous regions, focus on small and medium-sized mammals. This mammalian prey includes abundant species like rabbits, hares, ground squirrels, prairie dogs, marmots, and voles. Larger eagles, such as the Golden Eagle, are also capable of taking down young ungulates, including deer fawns, sheep, and caribou calves, especially when other food sources are scarce.
Eagles are highly capable avian predators, regularly incorporating other birds into their diet. They commonly target:
- Waterfowl like ducks, geese, coots, and various seabirds.
- Smaller birds and even other raptors, including owls and falcons.
Reptiles and insects also form a part of the diet, especially for specialized species like the serpent eagles of the genera Circaetus and Spilornis, which predominantly hunt snakes. Lizards and large insects may be consumed as a main food source in certain tropical regions or as a supplement for juveniles.
Dietary Specialization by Habitat
Bald Eagles, for example, are aquatic hunters that thrive near large bodies of water such as coasts, lakes, and major rivers. Their proximity to water dictates a diet heavily reliant on fish. This reliance is reflected in their physical adaptations, such as the roughened texture on the undersides of their toes that helps them grasp slippery prey. Fish can constitute over 90% of a Bald Eagle’s diet in certain locations.
Conversely, the Golden Eagle is a terrestrial hunter, preferring the open country of mountains, prairies, and tundra. Their diet is dominated by mammalian prey, using their agility and powerful talons to capture animals on the ground. Although they primarily eat small mammals, Golden Eagles are known to occasionally take down larger prey, such as young goats or deer, demonstrating their immense strength.
Most eagle species exhibit highly opportunistic feeding habits, readily consuming carrion. This scavenging behavior is particularly pronounced during winter months or periods of low live prey availability. They will consume the remains of dead animals, such as roadkill deer or washed-up marine mammals, and are often seen feeding alongside terrestrial scavengers.
Hunting Strategies and Feeding Behavior
Eagles employ a variety of methods to secure their diverse meals. Active predation often involves soaring high on air currents, using their powerful eyesight to spot potential prey from a great distance. Once a target is identified, the eagle executes a fast, controlled dive, capturing the animal with its strong feet and sharp talons. Some species also utilize perch hunting, waiting patiently on an elevated branch before swooping down on unsuspecting prey.
A notable and frequent feeding strategy for many eagles is kleptoparasitism, which involves stealing food from other animals. Bald Eagles are particularly well-known for harassing smaller raptors, most often Ospreys, forcing them to drop their caught fish in mid-air, which the eagle then retrieves. This behavior provides an efficient way to obtain a meal without expending the energy required for a full hunt.
Once prey is secured, eagles use their powerful, hooked beaks to tear flesh into smaller, manageable pieces. Smaller prey, such as fish or small rodents, may be swallowed whole. Eagles possess a crop, a muscular pouch in the esophagus, which allows them to temporarily store up to two pounds of food, enabling them to consume a large meal quickly. Their digestive system is highly acidic, allowing them to digest bones for nutrients, while indigestible materials like fur and feathers are later expelled in a compact pellet.