Eagles are powerful birds of prey found on nearly every continent. As apex predators, they regulate populations of other animals, contributing to the health and balance of their ecosystems. Their adaptability and crucial role are evident in diverse natural systems.
Primary Avian Prey
Eagles incorporate various bird species into their diet, particularly when fish or mammals are less available. Bald Eagles, for instance, frequently prey on waterfowl such as ducks and geese. They also target gulls and other birds, especially those found on the ground. Large wading birds like great blue herons can also become prey for Bald Eagles.
Golden Eagles, while primarily preying on mammals, also consume birds, with game birds such as grouse and ptarmigan being significant. In some regions, grouse can constitute a substantial portion of their diet, sometimes even displacing mammals as the primary prey. Eagles often target these birds due to their size, behavior, or habitat overlap. For example, the large gatherings of waterfowl make them accessible targets for eagles, particularly during winter.
Hunting Strategies for Avian Prey
Eagles employ diverse hunting strategies to capture avian prey. They scan for prey from high perches or while soaring, using their exceptional eyesight to spot movement up to two miles away. Once prey is sighted, eagles may execute a high-speed dive known as a “stoop,” pulling in their wings to increase velocity and surprise the target. Golden Eagles can reach speeds of 150 to 200 miles per hour during a stoop.
Eagles also use aerial pursuit, snatching birds mid-air, especially slower-flying species like geese. Their powerful talons exert immense pressure for grasping and incapacitating prey. Bald Eagles have specialized feet with rough bumps, or spicules, that help them hold onto slippery prey. While often solitary hunters, Bald Eagles can sometimes engage in cooperative hunting, where one eagle might flush out prey while another intercepts it, particularly when targeting challenging prey like waterfowl.
Influences on Bird Prey Selection
Several factors influence an eagle’s choice of avian prey. Bald Eagles primarily inhabit areas near large bodies of open water and consume a diet largely composed of fish. Birds, including waterfowl, make up a significant but secondary portion of their diet, around 28%.
Golden Eagles prefer open landscapes such as mountains, forests, and grasslands, and their diet mainly consists of small to medium-sized mammals. While they hunt birds, their prey selection focuses on game birds found in their terrestrial habitats. Prey availability, influenced by seasonal changes like migration patterns, also affects what birds eagles hunt. The abundance of other food sources, such as fish or carrion, can reduce an eagle’s reliance on birds. During harsh winters when other prey is scarce, eagles may increase their scavenging behavior or target weakened birds.