Eagles sit at or near the top of most food chains they inhabit, but a handful of animals do hunt and kill them. The list is shorter than you might expect: other large raptors, certain nest-raiding mammals, parasites, and even an eagle’s own sibling. In practice, the single greatest source of eagle mortality is not any wild predator but human activity, which dwarfs every natural cause combined in well-studied populations.
Other Raptors and Large Owls
The most consistent natural predators of eagles are other birds of prey. A broad review of this kind of within-guild killing across raptor communities found it to be widespread and strongly driven by body size: larger species kill smaller ones, and the pattern holds across dozens of study populations spanning 11 killer species and 15 victim species.1Ibis. Intraguild predation in raptor assemblages: a review This means the very largest eagle species have almost no avian predators, while medium-sized eagles face real threats from their bigger relatives.
Great horned owls are among the most formidable raptor killers in North America. They hunt at night when eagles are roosting and vulnerable, and their powerful talons can kill birds their own size or larger. In parts of North America, great horned owls have been documented attacking juvenile bald eagles and occasionally killing adults at nest sites. Eurasian eagle-owls play a similar role across Europe and Asia, preying on a wide range of raptors including smaller eagle species. Because owls hunt in darkness, eagles have little ability to detect and evade them the way they might avoid a daytime competitor.
Among eagles themselves, size differences create predation opportunities. Golden eagles occasionally kill smaller raptors within their territory, and in regions where several eagle species overlap, the larger species may prey on the smaller. The key pattern is straightforward: killing flows from bigger to smaller, and eagles that are mid-sized within their local raptor community face the greatest threat from other raptors.
Mammals That Raid Nests
Several mammal species prey on eagles, though almost exclusively by targeting nests rather than catching adults on the wing. Bears are the most significant mammalian nest predators for many eagle populations. Both brown bears and black bears are capable climbers, and they will scale trees or cliff faces to raid eagle nests for eggs and nestlings. In parts of Russia’s Far East, brown bears have been documented climbing to Steller’s sea eagle nests, destroying nest structures and consuming the contents. For tree-nesting eagles in bear habitat, this kind of nest predation is a meaningful source of reproductive failure year after year.
Wolverines, though rarely caught on camera in the act, are known to raid ground-level and low-cliff nests of golden eagles in arctic and subarctic regions. Their climbing ability and sheer tenacity make them one of the few mammals that can threaten even a well-defended eagle nest. Raccoons and martens can also reach tree nests and take eggs or small nestlings, though they pose little danger to older eaglets large enough to fight back.
On the ground, eagles occasionally fall to terrestrial predators. Coyotes, wolves, and foxes can kill an injured or grounded eagle, particularly one that is feeding on a carcass and slow to take flight. These encounters are opportunistic rather than habitual. A healthy adult eagle in the air is simply too fast and powerful for any ground-based mammal to catch, so mammalian predation of eagles is overwhelmingly concentrated at nests or involves birds that are already weakened.
When the Killer Is a Sibling
One of the most reliable killers of young eagles is not an outside predator at all. In many eagle species, the first-hatched chick dominates its younger sibling through aggression, food monopolization, and outright attack. This behavior is strikingly common: a review across birds of prey identified 23 species in which regular siblicide occurs, either as an obligate pattern in virtually every nest or as a facultative response to conditions.2Ibis. Offspring quality and the evolution of cainism Researchers have tried adding extra food to nests and even raising two same-sized chicks together experimentally, and the aggression persists regardless. This is not a simple response to hunger.
In obligate-siblicide species like the lesser spotted eagle, the second chick almost never survives. The critical factor turns out to be the interval between hatching. If the older chick has even a small head start, it quickly learns to take food offered by the parent and dominates every feeding. The younger chick is intimidated, stops competing, and retreats to the edge of the nest, where it starves. Outright killing is actually extremely rare; what happens is a slower process of exclusion. Once the younger bird accepts its subordinate position, it simply never participates in feeding again.3Ibis. Sibling aggression and mortality among nestling eagles
For many eagle species, this means the single greatest source of nestling mortality is not a raccoon raiding the nest or a storm toppling the tree. It is the other egg that hatched a day or two earlier.
Parasites and Disease
Eagles also face lethal threats from organisms far too small to hunt them in any conventional sense. Parasitic infections can be just as fatal as a predator’s talons, particularly for birds already stressed by food scarcity or environmental contamination.
One documented example involves Sarcocystis falcatula, a protozoan parasite typically cycling between opossums and certain bird species. In North America, three bald eagles and one golden eagle were found with severe infections that had spread to their lungs, brains, skeletal muscles, and hearts. All four birds were emaciated, lethargic, and unable to fly, and all four died. These represented the first confirmed cases of natural S. falcatula infection killing eagles.4PubMed. Natural fatal Sarcocystis falcatula infections in free-ranging eagles in North America Eagles likely pick up the parasite by eating infected prey, making this a hazard built into the food chain itself.
Lead poisoning functions as a kind of slow-motion predation too. Eagles that scavenge carcasses or gut piles left by hunters frequently ingest lead ammunition fragments. The lead accumulates in their tissues, causing neurological damage, muscle weakness, and eventual death. Avian influenza, West Nile virus, and various bacterial infections also kill eagles, particularly during outbreaks. While these agents are not “predators” in the way most people picture the word, they are among the forces that most reliably end eagle lives in the wild.
Humans Are the Biggest Killer by Far
For all the wild predators and parasites that threaten eagles, none comes close to the toll from human activity. A large-scale study of golden eagle mortality in the western United States found that after the first year of life, human-caused deaths accounted for roughly three-quarters of all mortality where a cause could be determined.5PubMed Central. Age-specific survival rates, causes of death, and allowable take of golden eagles in the western United States No bear, owl, or rival eagle kills hundreds of golden eagles per year in a single country. But shooting alone accounted for an estimated 670 golden eagle deaths annually in the western U.S., with collisions adding about 610 more, electrocutions roughly 500, and poisoning around 430.5PubMed Central. Age-specific survival rates, causes of death, and allowable take of golden eagles in the western United States
For bald eagles in North America, the pattern is similar. Lead poisoning from scavenged ammunition, collisions with vehicles and structures, and electrocution on power lines are the dominant causes of death. Historically, the pesticide DDT drove bald eagle populations to critically low levels before it was banned in the 1970s. Wind turbines have added another mortality source in recent decades, though at lower absolute numbers than the longer-established causes.
This picture holds globally: wherever eagle populations have been studied carefully, human-caused mortality exceeds natural predation by a wide margin. The practical effect is that conservation work for most eagle species focuses far more on reducing collisions, poisoning, and electrocution than on managing wild predators.
Why So Few Animals Can Threaten a Healthy Adult Eagle
The short predator list reflects the physical reality of what eagles are. Adult eagles are large, powerfully built, armed with talons that exert enormous grip force, and capable of sustained flight speeds no terrestrial predator can match. A harpy eagle in the Amazon, for instance, regularly hunts sloths, primates, and other mammals high in the canopy. Sloths alone made up about 78% of the prey items recorded at harpy eagle nests in one Brazilian study, with primates accounting for roughly 11%.6BioOne (Journal of Raptor Research). Food Habits of the Harpy Eagle, a Top Predator from the Amazonian Rainforest Canopy Almost all of its prey consists of arboreal species, and nothing in the forest canopy hunts the harpy eagle back.
Wedge-tailed eagles in Australia occupy a similarly commanding position. Studies of their diet have recorded prey as varied as dingoes, foxes, feral cats, reptiles, and even sheep.7PubMed Central. Irrupting prey populations in the absence of a mammalian apex predator drive shifts in prey selection by eagles An animal that regularly kills dingoes and foxes has very little to fear from local wildlife. The wedge-tailed eagle’s primary threats, like those of most large eagle species, come from humans through poisoning, collisions, and habitat degradation.
The consistent global pattern is that the larger the eagle, the fewer natural predators it has. The very largest species have essentially no regular wild predators as adults. Medium-sized eagles face occasional threats from great horned owls or larger eagle species, and all eagles are vulnerable at the nest stage, but a fully grown, healthy adult of the biggest species has functionally exited the food web as a prey item.
Invasive Species and Cascading Effects
Human activity reshapes eagle predation dynamics in subtler ways than direct killing. When invasive species enter an ecosystem, they can rearrange the entire predator-prey landscape in ways that put eagles in unfamiliar ecological positions. A well-studied case involves the Channel Islands off the California coast, where feral pigs attracted golden eagles to islands where they had not previously been resident. Once established, the eagles began preying heavily on the native island fox, nearly driving it to extinction. Researchers studying the situation found that the sequence in which invasive species were removed had major consequences for whether native species could recover.8PLOS ONE. Does the Order of Invasive Species Removal Matter? The Case of the Eagle and the Pig
Eagles are flexible predators that adjust their diets based on prey availability. In Australia, irrupting populations of native prey species have been shown to drive shifts in what wedge-tailed eagles target, with the birds switching emphasis as different prey populations boom and crash.7PubMed Central. Irrupting prey populations in the absence of a mammalian apex predator drive shifts in prey selection by eagles This dietary flexibility is part of what makes eagles so successful as apex predators, but it also means their ecological role shifts with changing conditions. When large mammalian predators are removed from a landscape, eagles sometimes expand into that niche. Conversely, when new competitors or prey species arrive, eagle behavior and distribution can change in ways that create new vulnerability.
Vulnerability Windows Across an Eagle’s Life
Eagles are not uniformly difficult to kill throughout their lives. Eggs and very young nestlings are defenseless against any predator that can reach the nest, from crows stealing eggs to snakes climbing tree trunks. Fledglings that have recently left the nest but are still mastering flight spend time on the ground, making them accessible to foxes, coyotes, and other terrestrial predators during a window of a few weeks.
Juvenile eagles in their first year face the highest natural mortality rates of any age class. They are inexperienced hunters, more likely to scavenge in dangerous locations like roadsides, and less skilled at avoiding threats. Many of the human-caused deaths documented in studies of golden eagle mortality involved younger birds that had not yet developed the wariness of adults.5PubMed Central. Age-specific survival rates, causes of death, and allowable take of golden eagles in the western United States
Adult eagles in breeding condition also carry slightly elevated risk, because nesting ties them to a fixed location for months. A breeding pair returns repeatedly to the same nest, making their movements predictable to any predator that has learned to exploit the pattern. Great horned owls sometimes take over eagle nests before the eagles return in spring, creating territorial conflicts that can injure or kill either bird. Still, a healthy adult eagle on the wing, away from a nest, and free of injury or disease, is close to untouchable by wild predators. The combination of size, flight speed, acute vision, and weaponry makes a full-grown eagle one of the most formidable animals alive, and that is precisely why the list of things that hunt them remains so short.