Bald eagles are both scavengers and hunters, and they shift between the two strategies depending on the season, their age, and what food is easiest to get. Describing them as one or the other misses how they actually live. They are opportunistic foragers that actively hunt fish, waterfowl, and small mammals when live prey is available, but they just as readily feed on carrion, steal meals from other birds, and pick through whatever dead animals the landscape offers. The mix of tactics is not a quirk but a core part of how these birds make a living across a huge range of habitats.
Active Hunting and What Bald Eagles Catch
Fish make up the largest share of a bald eagle’s diet across most of its range. The classic image of an eagle swooping down to snatch a fish from the water’s surface is not exaggerated. They patrol rivers, lakes, and coastlines, spot fish from high perches or while soaring, and dive feet-first to grab prey near the surface with their talons. They are not deep divers like ospreys, so they target fish swimming in shallow water or near the top. Salmon, trout, catfish, shad, and herring are all common prey depending on the region.
But fish are far from the whole story. Bald eagles also hunt birds, especially waterfowl like coots, ducks, and grebes. They will chase down seabirds, raid colonial nesting sites for eggs and chicks, and even take small mammals such as rabbits, muskrats, and ground squirrels when the opportunity arises. In coastal Alaska, they have been documented preying on sea otter pups. They hunt cooperatively on occasion too, with pairs or small groups flushing prey toward each other. The point is that these are capable, adaptable predators with genuine hunting skill, not animals that merely pick at leftovers.
Why Scavenging Is Equally Central
If hunting were the whole picture, bald eagles would not gather in enormous winter congregations along rivers where spawned-out salmon carcasses pile up by the thousands. Scavenging is not a fallback for lazy or unskilled birds. It is a deliberate, energy-efficient strategy that bald eagles rely on heavily, especially in winter when live prey becomes scarce and the metabolic cost of staying warm is high.
Carrion sources vary by habitat and season. Along Pacific Northwest rivers, dead and dying salmon after the spawning run create a seasonal feast that draws hundreds or even thousands of eagles to a single stretch of river. In the Midwest and East, deer carcasses left by hunters, roadkill, and winterkill fish frozen out of shallow lakes are major food sources. Along coastlines, dead seals, sea lions, and whale carcasses attract eagles. In agricultural areas, they feed on livestock afterbirth and dead farm animals. The common thread is that bald eagles are always watching for an easy meal, and dead animals are about as easy as it gets.
Research on overwintering bald eagles has shown that they are remarkably good at conserving energy. A study in the upper Midwest found that wintering eagles maximize energy gain by foraging in groups, gorging when food is available, and extracting more energy from food during cold stress. They minimize energy loss by becoming sedentary, seeking sheltered roost sites in coniferous forests, and reducing their body temperature at night. Even the choice of roost location reflects this calculus: eagles roosted in coniferous forest even though they had to fly farther to reach it, because the windbreak provided a net daily energy savings of about five percent of their total daily energy budget after accounting for the flight costs.1Ecological Monographs. Ecological Energetics and Foraging Behavior of Overwintering Bald Eagles In a bird running this kind of tight energy budget, grabbing a dead fish or a deer carcass instead of chasing live prey makes perfect sense.
Kleptoparasitism, or Why Benjamin Franklin Was Not Entirely Wrong
Benjamin Franklin famously grumbled that the bald eagle was “a Bird of bad moral Character” that “does not get his Living honestly.” He was referring to kleptoparasitism, the practice of stealing food from other animals, and on this point he was observationally correct even if morally judgmental. Bald eagles are prolific food thieves. They routinely harass ospreys carrying fish, chasing them in flight until the osprey drops its catch, then swooping down to grab the stolen meal before it hits the water. They do the same to other eagles, herons, and even hawks carrying prey.
Kleptoparasitism blurs the line between hunting and scavenging in an interesting way. The eagle is not catching its own prey, but it is not feeding on something already dead either. It is using its size and aggression to muscle a smaller bird out of a meal. This is energetically cheaper than catching a fish from scratch but requires the eagle to be in the right place at the right time and to be large and aggressive enough to win the confrontation. Adult bald eagles, which are bigger than most of the raptors they steal from, have a clear advantage.
How Age Shapes Foraging Strategy
One of the most interesting patterns in bald eagle foraging is the way it changes with age. Young eagles, especially birds in their first and second years, are not yet skilled hunters. Their fishing success rate is poor compared to experienced adults. This means juveniles rely more heavily on scavenging and on exploiting easy, low-quality food sources while they develop their hunting abilities.
A study of bald eagle use of an urban landfill in Vancouver found that the dump was not a major energy source for most eagles, partly because the large number of birds competing there made foraging inefficient. Most eagles visited the landfill only occasionally, spending the majority of their time elsewhere. But a small population of mostly young, subadult birds appeared to be “refuse specialists,” gaining much or all of their energy from the landfill.2The Wilson Journal of Ornithology. Foraging Ecology of Bald Eagles at an Urban Landfill A broader review of how garbage dumps affect wildlife reached a similar conclusion: rubbish dumps serve as important scavenging sites for first-year and second-year bald eagles, while older birds are more successful at obtaining higher-quality food elsewhere.3Global Ecology and Conservation. How are garbage dumps impacting vertebrate demography, health, and conservation?
This age-related shift makes ecological sense. A young eagle that cannot reliably catch fish needs to eat something, and carrion, garbage, and easy scavenging opportunities keep it alive during its steep learning curve. As an eagle matures and its hunting skill improves, the payoff of catching fresh, high-quality prey increases relative to the energy return from scavenging scraps. Adults still scavenge freely when it is efficient to do so, but they have more options.
Competition at Carcasses
When a bald eagle finds a carcass, it is rarely the only animal interested. Carcass feeding creates a competitive arena where eagles interact with coyotes, ravens, crows, vultures, other eagles, and occasionally other raptor species. Within these gatherings, size usually wins. A full-grown bald eagle is one of the largest raptors in North America, with females weighing up to about 14 pounds, and it can usually dominate smaller birds at a feeding site through posture, wing displays, and direct aggression.
Interestingly, dominance at carcasses does not always follow the pattern you might expect among related eagle species. Research on white-tailed sea eagles (a close European relative of the bald eagle) and golden eagles feeding at carcasses in Norway found that the smaller golden eagles were strongly dominant over the larger sea eagles in direct competition for carcass access. Among sea eagles, females dominated males, and most conflicts were won by the aggressor, suggesting that birds could generally assess relative dominance before picking a fight.4Ibis. Inter‐ and intra‐specific dominance relationships and feeding behaviour of Golden Eagles Aquila chrysaetos and Sea Eagles Haliaeetus albicilla at carcasses While this study focused on European species rather than North American bald eagles, the dynamics are instructive: being larger does not automatically mean being dominant at a carcass, and temperament and aggression matter as much as body size.
For bald eagles in North America, golden eagles are the primary raptor competitor at carcasses in areas where the two species overlap, particularly in the western states during winter. Ravens and crows also compete at carcass sites, though they typically feed around the edges while eagles occupy the prime position. The social dynamics at a carcass can be chaotic, and eagles frequently squabble with each other as much as with other species.
The Hidden Danger of Scavenging on Lead-Killed Prey
Scavenging comes with a risk that hunting does not: exposure to lead ammunition fragments. When a hunter shoots a deer with lead bullets, the bullet often fragments on impact, scattering tiny lead particles through the wound channel and into the gut pile or offal left behind in the field. Bald eagles feeding on these remains ingest the lead fragments, which can cause poisoning ranging from subtle neurological impairment to death.
A study on the U.S. Fish and Wildlife Service’s Upper Mississippi River National Wildlife and Fish Refuge investigated whether discarded offal piles from hunter-killed deer were exposing eagles to lead. Radiographs showed that roughly a third of offal piles in the study area contained lead fragments, with individual piles holding anywhere from 1 to 107 particles. The study concluded that lead exposure rates for bald eagles found dead in the Upper Midwest were high, and that more than a third of bald eagles found dead in Iowa, Minnesota, and Wisconsin had liver lead concentrations consistent with lead poisoning.5Journal of Fish and Wildlife Management. Bald Eagle Lead Exposure in the Upper Midwest
Lead poisoning from scavenged ammunition is now recognized as one of the leading causes of bald eagle mortality in many parts of the United States, even as the overall population has recovered dramatically from its mid-twentieth-century low. The irony is that the eagle’s scavenging behavior, which served it so well through millennia of evolutionary history, has become a vulnerability in the modern landscape. Some states and refuges have responded by encouraging or requiring the use of non-lead ammunition, particularly copper bullets, in areas with significant eagle populations. Voluntary lead-ammunition buyback and exchange programs have also been tried with varying success.
Mercury and the Cost of Fish Predation
If scavenging exposes eagles to lead, their primary hunting behavior exposes them to a different toxicant: mercury. Because bald eagles sit at the top of aquatic food chains, mercury that enters waterways and accumulates up through invertebrates, small fish, and larger fish ends up concentrated in the eagles that eat those fish. This process, called biomagnification, means that eagles in areas with mercury-contaminated watersheds can carry substantial mercury burdens.
A study of bald eagle nestlings in Maine measured mercury concentrations across different habitat types within a watershed that included a former industrial mercury source. Mercury levels in nestlings varied significantly by habitat, with birds raised along freshwater rivers and lakes carrying higher concentrations than those in marine and estuarine habitats. Strikingly, nestlings raised in freshwater habitats far from the industrial contamination source still had higher mercury levels than those near it in coastal areas, because freshwater ecosystems naturally convert and concentrate mercury more efficiently than marine ones.6Science of The Total Environment. Mercury concentrations in bald eagles across an impacted watershed in Maine, USA
The practical takeaway is that both of the eagle’s main foraging strategies carry distinct environmental risks. Scavenging on hunter-killed game brings lead exposure. Hunting fish brings mercury exposure. Neither risk is sufficient to threaten the species as a whole at current population levels, but both create localized problems and contribute to individual bird mortality in contaminated areas. For wildlife managers, this means that protecting bald eagles requires thinking about pollution sources in both terrestrial and aquatic environments.
Why the “Scavenger” Label Bothers People
There is a persistent cultural discomfort with calling the national bird a scavenger. It sounds undignified, like calling a lion a garbage picker. This cultural bias goes all the way back to Franklin’s complaint and has shaped how many people think about bald eagles. School textbooks and nature documentaries tend to emphasize the hunting side, showing dramatic fish grabs and aerial chases, while downplaying or ignoring the hours an eagle might spend sitting on a deer carcass in a ditch.
Ecologically, scavenging is not a lesser strategy. Vultures are obligate scavengers, meaning they depend entirely on carrion, and they play a critical role in nutrient cycling and disease prevention. Bald eagles are facultative scavengers, meaning they scavenge when it benefits them but can also hunt. This flexibility is one of the reasons they are so successful across such a wide geographic range, from the Aleutian Islands to Florida. An animal that can hunt fish in summer, scavenge salmon carcasses in fall, steal food from ospreys in spring, and pick at deer remains in winter is an animal that can survive almost anywhere there is water and some open habitat.
The question of whether bald eagles are scavengers or hunters sets up a false choice. They are generalist predators with a strong scavenging habit, and neither label alone captures what they do. If anything, the ability to switch between strategies as conditions demand is the defining feature of their foraging ecology, and it is a large part of what makes them one of the most successful raptors on the continent.
Landfills, Fish Hatcheries, and Other Human-Created Food Sources
Bald eagle populations have boomed since the ban on DDT and the protections of the Endangered Species Act, and their recovery has brought them into increasing contact with human food sources. Landfills, fish processing plants, hatcheries, livestock operations, and even urban dumpsters now feature in the bald eagle diet in some areas. Eagles gathering at landfills in large numbers can create conflicts with aviation (airports near dumps are particularly affected), and the birds can spread garbage across surrounding neighborhoods.
The Vancouver landfill study found that most eagles treated the dump more as a place to rest during bad weather than as a primary food source, with only a few young birds making it a dietary staple.2The Wilson Journal of Ornithology. Foraging Ecology of Bald Eagles at an Urban Landfill That pattern seems to hold elsewhere: landfills attract eagles, but the competition among so many birds and the low nutritional quality of garbage mean that dumps are most useful for young, inexperienced birds that do not yet have better options. As eagles mature and get better at fishing, most move on to higher-quality food sources.
Fish hatcheries present a different dynamic. Where hatcheries release juvenile fish, eagles can pick off easy meals with little effort. Some hatcheries have installed netting or other deterrents, but the sheer number of eagles in recovered populations makes exclusion difficult. Similarly, aquaculture operations raising trout or catfish in open ponds can attract eagles, creating economic conflicts with fish farmers. These situations illustrate the broader reality that bald eagles are supremely practical foragers. They do not distinguish between a “wild” fish and a hatchery fish, or between a “natural” carcass and a deer gut pile. If it is edible and accessible, they will eat it.
Energy Budgeting in Practice
The way bald eagles allocate their foraging effort makes more sense when you think about energy as a currency they are constantly trying to maximize. Catching a live, healthy fish requires flight energy, precise timing, and a success rate that may be well under fifty percent on any given strike. Eating a dead salmon lying on a gravel bar requires almost no energy expenditure at all. The tradeoff is that the dead fish may be partly decomposed and lower in caloric value, and the eagle may have to compete with other scavengers for access to it.
Overwintering eagles demonstrate this energy calculus most clearly. The research on energy budgets showed that wintering eagles employ a suite of energy-conserving behaviors: they become sedentary, forage in groups (which may help locate food more efficiently), gorge themselves when they find food so they can go longer between meals, and seek microclimates that reduce heat loss at night.1Ecological Monographs. Ecological Energetics and Foraging Behavior of Overwintering Bald Eagles In winter, the balance tips heavily toward scavenging because the energy cost of active hunting is high and the availability of carrion from winter die-offs is often good. In summer, when fish are abundant and daylight hours are long, active hunting becomes more profitable and eagles do more of it.
Breeding adults face an additional constraint: they need to bring food back to nestlings, and nestlings need relatively fresh, high-quality protein to grow. This pushes breeding eagles toward more active hunting during the nesting season, particularly fishing. A breeding pair near a productive lake or river may hunt almost exclusively during chick-rearing, switching back to a mixed strategy once the young have fledged. The foraging profile of a bald eagle is not fixed; it shifts with the bird’s age, the season, the local food supply, and whether it has mouths to feed at the nest.