Eagles are carnivores, which means that they feed only on meat. Some species of eagles are scavengers, which means that they primarily eat fish and animals that are already dead. Eagles also hunt their prey, though some species actively hunt more than others.
According to Eagle Nature, the American bald eagle's diet consists of 60 to 90 percent fish. Most of this is scavenged as dead fish, though bald eagles do hunt and catch live fish as well when they are available. The type of fish caught depends on location; eagles typically hunt and scavenge whichever type of fish is prevalent. Mullet and black fish, which swim near the surface, are likely prey. The remainder of the bald eagle's diet consists of smaller birds, including herons and crows, as well as chickens and small pigs. They have also been known to chase other birds of prey, snatching their food once they drop it.
Eagles do not need to eat every day. They have a special digestive organ known as the crop, which stores food until there is room for it in the stomach. This allows them to store a large meal until it is later needed, and prevents the eagle from growing weak if food is scarce for several days or weeks.