Referred to as the “broken-wing display,” birds like the killdeer feign injury in order to divert predators away from their nest.
Out of the over 10,000 species of birds that exist today, many possess various tactics to protect themselves from predators. They can escape by flying, running, or swimming, attack predators with their sharp talons and beaks, or blend into their surroundings like the nightjar. However, scientists have recently discovered that certain birds take it a step further by becoming masters of defensive deception.
Commonly known as injury-feigning, distraction display, or the broken-wing display, this behavior refers to a tactic used by animals to divert attention or deceive predators.
Certain avian species utilize tactics that entail showcasing artificial signs of vulnerability with the aim of safeguarding their offspring from predators. They cleverly employ a deceptive scheme designed to divert the attention of potential threats away from their young and towards their own presence.
What Species Demonstrate the Broken-wing Display?
Initially, scientists observed this behavior exclusively in coastal birds.
The killdeer is a shorebird that is known for its unique call and its ability to deceive predators. Many predators, including hawks, owls, falcons, herring gulls, crows, raccoons, skunks, and feral cats, see the killdeer as an easy meal. To outsmart these predators, the killdeer pretends to have a broken wing. It lays its camouflaged eggs in rocky crevices, which are not completely inaccessible to predators.
By acting as bait, the killdeer distracts the predators from its offspring. It starts to move away from the nest, making loud squawking noises and dragging its tail and wings as if it is injured. This behavior continues until the killdeer is confident that it has fooled the predator. Then, it “recovers” and flies away unharmed. This strategy has proven to be successful for the killdeer in protecting its young.
Oystercatchers are another bird species that also use deception to protect their nest. They produce distress calls and lead predators away from their nest site by pretending to be injured. Eventually, the predator loses track of the nest’s location, and the oystercatcher stops pretending to be hurt and flies away. Studies have shown that this tactic is successful in 90% of cases.
Overall, both the killdeer and oystercatchers have developed clever strategies to outsmart predators and ensure the safety of their offspring.
What is the Reason for the Limited Use of this Technique by Birds?
The behavior of certain birds, which involves them pretending to be Trojan horses, has puzzled ornithologists and animal behaviorists. They questioned why these particular birds adopted such a strategy.
Further study and observation have revealed that shorebirds are not the sole practitioners of this deceptive behavior. Scientists have now identified approximately 300 bird species that employ similar tactics.
Scientists examined sixteen different characteristics of bird species that exhibit the “broken-wing display,” including size, breeding location, and nest hiding strategies. By comparing these characteristics, a pattern emerged. Species that nested at higher latitudes were more likely to perform the broken-wing act compared to their counterparts that lived in tropical regions. Similarly, species that laid their eggs on the ground or in vulnerable areas were more prone to showing this behavior.
For instance, birds like woodpeckers, trogons, and waterthrushes lay their eggs in tree cavities that are safe from predators. Deceptive behavior was rarely observed in these species.
In essence, the frequency of predation each species faces determines their likelihood of performing the broken-wing display.
Is the Broken-Wing Display Learned or Genetic?
While there is no doubt that these birds feign having broken wings, the question remains: is this behavior intentional or instinctive? Was it passed down genetically or is it a well-planned deception?
In a 1993 study, researchers conducted 45 trials where humans approached a Plover’s nest. In almost all cases, the bird successfully led the predator away from its nest. Furthermore, they made sure to stay close to the predator before performing the broken-wing display. They even turned back to check if their act was working! Since differences in predation pressure greatly influence the evolution of the broken-wing display, it is likely that this behavior is learned through exposure to various predators. As this tactic increases the species’ chances of survival, it was quickly adopted and integrated as a defense mechanism.
An American golden plover (Photo Credit : Agami Photo Agency/Shutterstock)
Final Reflections
Within the bird community, certain species exhibit the broken-wing display, whereas other species who are closely related do not partake in this behavior. This implies that, from an evolutionary standpoint, birds that required a more assertive means of protecting their offspring chose to adopt this particular form of defense.
Therefore, the next time you encounter a bird feigning a broken wing, take into consideration that it could simply be a cautious mother bird. Take some time to observe it, as you wouldn’t want to unintentionally disturb its nest!