Meet 4 ‘Killer' Birds That Have Been Known To Attack People — Explained By A Biologist

Forbes

08-06-2025

Do you know what the world's most deadly animal is? I'll give you a hint. It has wings and is capable of flight – but it's not a bird. The answer? A mosquito.
Mosquitoes are a true scourge, responsible for up to one million human deaths per year.
Mosquitoes aren't deadly from their bites alone – though, to be fair, a swarm of mosquitos is not something to overlook as they can kill cattle, horses and other large mammals in rare cases.
Rather, what makes them so dangerous are the diseases they carry – malaria, dengue, yellow fever and others.
Birds, on the other hand, can also be dangerous to humans due to the contagions they carry – the most common being avian flu, or H5N1. Nevertheless, the danger posed by bird flu is orders of magnitude less than that of malaria. To give some context, confirmed human deaths from bird flu over the past two decades is less than 500. I repeat: mosquitoes kill up to a million people per year.
The odds of human death or injury by bird attack is even more remote. But it does happen. When it does, it's often inflicted by one of the following four bird species – two of which we have documented evidence of human fatalities.
Southern cassowary (Casuarius casuarius).
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Often dubbed 'the world's most dangerous bird,' the cassowary (Casuarius spp.) lives in the rainforests of northern Australia and New Guinea. These flightless birds are striking in appearance – bright blue skin, a helmet-like casque on their heads, and dagger-like claws on each foot. While they are usually shy and elusive, cassowaries can become highly aggressive if they feel threatened, especially during breeding season or when defending chicks.
Their most fearsome weapon is a sharp, curved claw on each foot, which can grow up to 5 inches long. With a single kick, they can slash open skin and sever arteries.
One of the first documented fatal cassowary attacks occurred in Australia in 1926, when a 16-year-old boy reportedly tried to club and kill the bird. The cassowary kicked him in the neck, severing his jugular vein. He died shortly afterward from his injuries.
More recently, a 75-year-old man was killed by a cassowary at an exotic animal breeding farm in Florida, where the bird was being kept in captivity. The man suffered more than a dozen lacerations from the bird's sharp claws and died shortly after paramedics arrived on the scene.
Many other attacks have been reported in Australia, though most are non-fatal.
Australian magpie (Gymnorhina tibicen).
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Australian magpies (Gymnorhina tibicen) are notorious for their aggressive swooping behavior during breeding season, particularly from August to October. Found throughout Australia, these medium-sized birds are highly territorial and will defend their nests with surprising boldness against much larger intruders, including humans. Cyclists, joggers, and walkers are common targets, especially if they inadvertently stray too close to a nesting site.
Attacks usually involve fast, low swoops from behind, often accompanied by loud squawking. While many incidents result in no more than a scare, some have caused eye injuries, concussions, or cycling accidents. There have been reports of people crashing their bicycles while trying to avoid swooping magpies, leading to broken bones or worse.
In rare cases, efforts to avoid these swooping birds have ended in tragedy. In 2019, a 76-year-old man from Sydney died from head injuries sustained in a bicycle accident while trying to evade a swooping magpie.
Experts suggest that not all magpies are aggressive. Only about 10% of male magpies engage in this behavior, and they often remember individual humans they perceive as threats. Wearing sunglasses on the back of your head, using zip-ties on helmets, or avoiding known nesting areas during breeding season are all common countermeasures.
(Sidebar: While the birds discussed here attack humans only in self-defense or to defend territory, meet two birds of prey that may have viewed humans as a source of food: one is recently extinct and the other lives on in this region of the Americas.)
Ostrich (Struthio camelus).
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The ostrich (Struthio camelus), the world's largest bird, may not be able to fly but its long legs and stature make it a serious threat if provoked. Native to Africa, ostriches can stand over 9 feet tall and weigh upwards of 300 pounds.
Their long legs are incredibly powerful, capable of delivering a deadly kick with sharp, clawed toes. These kicks are strong enough to kill large predators like lions, and can easily injure or kill a human.
Ostriches are generally peaceful grazers, but during breeding season or when cornered, they can become extremely defensive. Males, in particular, are known to be aggressive when guarding a mate or nest. Attacks on humans typically occur in captivity or farming situations, where humans may unknowingly enter their territory.
Emu (Dromaius novaehollandiae).
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The emu (Dromaius novaehollandiae) is Australia's second-largest bird after the cassowary and, while less aggressive, it can still pose a threat under certain conditions. Emus are curious, fast-moving, flightless birds that can reach speeds of up to 30 miles per hour and stand over 6 feet tall. Unlike cassowaries, they lack a killing claw, but their powerful legs can inflict serious damage with a kick or shove.
Emus are not naturally aggressive toward humans, but like any large wild animal, they can become defensive if startled, provoked, or protecting their territory. Incidents involving emus typically occur in captivity or areas where humans have fed them and altered their natural behavior. In some tourist regions, emus have been known to chase people for food or become overly familiar – leading to head-butts, pecking or the occasional knockdown.
During Australia's infamous 'Emu War' in 1932, soldiers struggled to control large flocks of emus that were damaging crops – highlighting both the bird's resilience and wariness. While the emu's reputation is more comedic than fearsome, it's important not to underestimate these towering birds. Giving them space and not feeding wild animals are all key to peaceful coexistence.
Are you an animal lover who owns a pet, perhaps even a (friendly) pet bird? Take the science-backed Pet Personality Test to know how well you know your animal.