Buzz
This is a follow-up to my earlier list, 10 Mammals with Unusual Defenses. While most birds can take to the skies, using flight as an effective defense against predators, with more than 10,000 species of birds, it's no surprise that some have evolved truly unconventional defenses.
Here’s a brief list of birds with surprising and unconventional defense strategies. If you think of any other bird that deserves to be on this list, feel free to share it in the comments!
10. Fulmar Chick
The fulmar is a seabird closely related to the more famous albatross. The name fulmar is derived from the Norse words 'ful-mar,' which translates to 'foul gull,' and for good reason. These birds are notorious for their unbearable stench; not only do the birds themselves reek, but their eggs do as well! Even after a century in museum storage, fulmar eggs still emit their pungent, nauseating odor.
While the fulmar's foul odor serves as a deterrent to some predators, like humans, it doesn't deter all predators. This is because birds typically have a poor sense of smell and aren't bothered by their prey's unpleasant scent.
Unable to fly or escape from danger, fulmar chicks have developed an extraordinary yet unpleasant defense. When threatened, they projectile vomit a bright orange, irritating oil from their stomachs. This substance not only stinks but also sticks to a predator’s feathers (or fur), matting them and causing a loss of insulation. If the feathers become waterlogged, the predator may die from exposure or even drown, making fulmar chicks not only unappetizing but also highly dangerous to potential predators.
Interestingly, while adult fulmars can also spit oil, it is the chicks that have far better aim and can do so repeatedly. Some chicks are capable of spitting as soon as they are born, with reports of them spitting even before fully hatching from their eggs.
Fulmars themselves are immune to the oil on their feathers, which is crucial because very young fulmar chicks will not only spit at predators but also at any creature that comes too close—including their parents. They only start recognizing their parents and holding back their defensive spitting around the age of three weeks.
9. Hoopoe
Native to Africa, Europe, and Asia, and recently designated as Israel’s national bird, the hoopoe is a close relative of kingfishers. It is known for its distinctive flight pattern (reminiscent of a butterfly), its striking feather crest, and its unpleasant defensive mechanism.
The hoopoe has a specialized gland near its anus that produces a foul-smelling substance. The bird applies this secretion to its feathers, enveloping its body in the stench of decaying flesh. Not many predators are keen on feasting on such a repulsive-smelling bird. In addition to its offensive odor, this substance also serves as a repellent to parasites and acts as an antibacterial agent, shielding the hoopoe from various diseases.
Interestingly, adult hoopoes only produce this unpleasant secretion when incubating eggs and caring for their young. Once the chicks leave the nest, the mother ceases to produce the noxious substance.
Baby hoopoes have their own unique defense strategy. When threatened while alone at the nest, they squirt their feces directly into the predator's face. It's a highly effective way to deter unwanted intruders.
8. Killdeer
Killdeer are noisy birds primarily found in Canada, the United States, and Mexico. These birds nest on the ground, making their eggs and chicks especially vulnerable to predators.
To protect their nest, adult killdeer have developed a clever defense mechanism. When a land predator such as a cat, fox, or dog approaches, the adult bird feigns injury by dragging one wing as if it's broken, while flapping the other wing and emitting a distress call, leading the predator away from the nest.
Most predators will follow the seemingly vulnerable adult killdeer, rather than approaching the nest. However, if the predator persists, the 'injured' adult will crawl closer to the predator until it captures its full attention. Once enough distance is created between the nest and the predator, the adult killdeer takes off and flies away.
This deceptive behavior is known as the 'broken wing act.' It can be risky for the adult killdeer but has successfully saved many nests from being discovered and raided by predators.
Meanwhile, the killdeer chicks will typically run away from the nest while the predator is distracted by the adult.
Unfortunately, the 'broken wing act' only works with predators that are naturally drawn to vulnerable, injured prey. It is ineffective against large herbivores like cows and horses, which may still trample the nest.
7. Burrowing Owl
Burrowing owls inhabit prairies and deserts, stretching from Canada to Patagonia. They nest in burrows, often taking over abandoned burrows of other animals. If no empty burrows are available, they are capable of digging their own. Burrowing owl chicks are frequently left alone in the burrow by their parents, who must hunt for both themselves and their young. During this time, the chicks are vulnerable to predators like foxes, coyotes, ferrets, and house cats.
To protect themselves from these predators, burrowing owl chicks have developed a rare form of mimicry. When they feel threatened (for example, if an animal begins digging at the burrow entrance), the chicks emit a hissing sound resembling a rattlesnake's warning rattle. Since these venomous pit vipers often hide in burrows, most predators (including humans) instinctively flee upon hearing the dreaded sound of the rattle.
Adult burrowing owls also mimic the rattlesnake's sound when cornered inside their burrow. This remarkable defensive behavior is one of the most effective among birds. However, it has a weakness: it does not work against actual rattlesnakes. These reptiles are unlikely to be fooled by the owl's imitation, as they are deaf and cannot even hear their own rattle, let alone the mimic's. As a result, rattlesnakes remain one of the few predators that regularly prey on burrowing owl chicks.
6. Eurasian Cuckoo
The Eurasian Cuckoo is most famous for laying its eggs in the nests of other bird species. When the cuckoo chick hatches, it typically destroys the host bird's eggs or chicks, removing any competition and growing rapidly to a much larger size than its foster parents.
However, laying eggs in another bird's nest is not always easy or safe for the cuckoo, as many smaller birds are highly protective of their nests.
To shield itself from possible attacks, the female cuckoo has evolved a striking resemblance to a Sparrow Hawk, a raptor that preys on smaller birds.
By mimicking a fearsome predator, the cuckoo can scare off other birds from their nests. As long as the false Sparrow Hawk is nearby, the other birds will avoid returning to their nest, allowing the cuckoo to lay its egg undisturbed and fly off without being noticed or harmed.
Humans have long observed that the Eurasian Cuckoo bears a resemblance to a Sparrowhawk. The Roman naturalist Pliny the Elder even speculated that Cuckoos had the ability to transform into hawks. Birds, however, seem unable to distinguish a cuckoo that mimics a hawk from a real sparrowhawk, and will often react with panic upon encountering either of them.
The hawk-mimicking tactic of the Eurasian Cuckoo is so effective that other cuckoo species have also evolved to mimic hawks. For instance, the South Asian Hawk-Cuckoo closely mimics the Shikra, a type of sparrowhawk, copying its flight patterns and even the way it perches.
5. Ferruginous pygmy owl
Though owls are commonly associated with hunting mice and other rodents, they also prey on small birds. These birds are so frightened by owls that they will often aggressively mob them, especially during the daytime when owls are less likely to hunt. This behavior, known as ‘mobbing,’ is a way for smaller birds to try to drive away a potential threat.
While mobbing might simply be an inconvenience for larger, more powerful owls, it can pose a real danger to smaller species, such as the Ferruginous pygmy owl. These tiny owls, no bigger than a fist, are adept hunters capable of capturing prey twice their size, making them a source of fear for all other small birds within their domain.
To defend itself against mobbing, the Ferruginous pygmy owl has evolved a clever strategy: two eye-like spots on the back of its head. These false eyes trick most small birds into thinking the owl is aware of their presence. Fearing retaliation from the owl’s gaze, birds often choose to either retreat or attack from behind, mistakenly aiming for the owl's back.
However, by attacking from behind, the birds are met with the owl’s real eyes, and their attempts might end with them becoming prey for the owl.
4. Hoatzin chick
Native to the rainforests of South America, the Hoatzin was once thought to be a ‘living fossil.’ Even today, its precise relationship to other bird species remains unclear. This bird is remarkable for several reasons; for instance, it feeds on tree leaves, an unusual diet for a bird, and it uses bacterial fermentation to digest its food, similar to the process in cows. This unique digestion method gives the Hoatzin a strong, manure-like odor, which has earned it the nickname 'stink bird.' However, its foul smell is not the reason it makes it onto this list.
Hoatzins typically build their nests in tree branches that hang over water. When threatened by a predator, the chicks jump into the water to escape. These chicks are skilled swimmers and divers, and once the danger has passed, they can climb back up the tree and return to their nests.
To aid in their escape, Hoatzin chicks possess two claws on each wing, resembling those of the Archaeopteryx and other bird-like dinosaurs. These claws are present only in young Hoatzins, disappearing as the bird matures and learns to fly, no longer needing to climb to evade predators. Although the Hoatzin is not the only bird with wing claws, it is by far the most famous, having sparked scientific debate ever since its discovery in 1776.
3. Hooded pitohui
Hooded pitohuis are native to New Guinea, and their method of defending against predators is both simple and remarkable—they are poisonous. These birds feed on specific types of beetles that contain a powerful neurotoxin alkaloid called batrachotoxin, the same poison found in the skin of South American poison dart frogs.
By consuming these beetles, the Hooded Pitohui becomes toxic, accumulating the batrachotoxin in their feathers and skin. Locals often refer to them as 'rubbish birds' because their toxicity makes them inedible unless the feathers and skin are removed, and the meat is cooked with charcoal.
Contact with a Hooded Pitohui can result in numbness, tingling, skin burns, and sneezing, as documented by scientists who have handled the birds. Consuming one would be even more hazardous. To warn potential predators of its toxicity, this bird sports a striking orange and black coloration, making it easily identifiable.
It is believed that Hooded Pitohuis may also smear the toxin onto their eggs and chicks to protect them from predators. What's more, the Hooded Pitohui is not the only poisonous bird; other species like the Variable Pitohui and the Blue Caped Ifrita, also from New Guinea, have been confirmed to be poisonous. There may be many other poisonous bird species yet to be discovered, even among those already known.
2. African white masked owl
This small owl, once largely unknown to the public, gained fame after being featured on a Japanese TV show that highlighted its fascinating defensive behavior. When faced with a smaller or less aggressive threat, the masked owl fluffs up its feathers and hisses to make itself appear larger and more intimidating. This common strategy among owls, including the larger species, is usually sufficient to drive away most enemies.
However, when faced with a larger, more powerful predator, the masked owl takes a different approach. Instead of trying to appear more menacing, it flattens its feathers and squints, making its eyes nearly invisible to the predator. By remaining still and blending in with its bark-like feathers, it mimics the appearance of a tree stump or branch, much like the potoo, thus avoiding the attention of the larger predator. The famous Japanese TV show clip above showcases a captive African masked owl responding to two predators: the Barn Owl and the mighty Verreaux's Eagle Owl, Africa's largest owl. Be sure to watch the entire clip – it's truly astonishing.
1. Potoo
Native primarily to Mexico, Central, and South America, these peculiar nocturnal hunters are often called 'ghost birds' due to their remarkable camouflage. The potoo preys on insects, bats, and small birds. During the day, it perches motionless on a tree, perfectly imitating a dead or broken tree stump. Its feathers closely resemble tree bark, and the slit in its eyelids allows it to see even when its eyes are closed.
Potoos generally remain completely still, even when approached by other animals or humans, only taking flight once they feel they have been spotted. Their camouflage is so effective that they are rarely noticed and have few natural predators. This remarkable disguise makes them extremely difficult to observe during the day. At night, however, they can be spotted because their eyes reflect light, glowing much like those of cats or owls.
While potoos are not the only birds to mimic tree stumps (Australian frogmouths and some nightjars are also known to do so), they are undoubtedly the most convincing.
