Pigeons, like all birds, possess ears and an acute sense of hearing. They do not have the external, cartilaginous ear flaps, or pinnae, characteristic of humans and other mammals, which is why their auditory organs are not immediately apparent. This lack of external ear structure is an adaptation that helps streamline their head for efficient flight.
Pigeons’ Ears: Location and Appearance
The pigeon’s auditory apparatus begins with a simple opening, known as the external auditory meatus, located on the side of the head slightly behind and below the eye. This opening is covered by a specialized patch of soft feathers called auriculars. These auricular feathers serve a dual purpose: they protect the delicate ear opening from wind, water, and debris during flight, without significantly muffling incoming sound.
Unlike the contour feathers on the rest of the body, auriculars have a more fan-like structure with larger gaps between the fibers, allowing sound waves to pass through virtually unobstructed. The absence of a large external pinna is a key difference from mammalian hearing, but it does not diminish the pigeon’s ability to locate and process sounds.
The Avian Auditory System
Sound waves that pass the auricular feathers enter a short external passage and cause the tympanic membrane (eardrum) to vibrate. The middle ear contains only a single auditory bone called the columella. This slender structure transmits vibrations from the eardrum to the inner ear, replacing the chain of three ossicles found in mammals. The columella is connected to the extracolumella, a cartilaginous extension that attaches directly to the tympanic membrane, and this single-bone system efficiently converts airborne sound into mechanical energy.
The inner ear contains the cochlea, the organ responsible for converting mechanical vibrations into nerve signals. While the mammalian cochlea is coiled, the avian cochlea is generally shorter and straight. It contains the sensory structure known as the basilar papilla.
How Pigeons Process Sound
Pigeons possess a wide hearing range that extends into ultra-low frequencies (infrasound). Humans typically hear sounds down to about 20 Hertz (Hz), but homing pigeons can detect infrasound as low as 0.05 Hz. Below 10 Hz, pigeons are at least 50 decibels more sensitive than humans.
This acute sensitivity is theorized to be a navigational tool, allowing them to detect distant natural phenomena. Natural sources of infrasound include ocean waves, earthquakes, and large-scale weather patterns, which can travel hundreds or thousands of kilometers. By hearing these low-frequency cues, a flying pigeon can orient itself based on sound wave fronts or predict weather changes. When released for a flight, a pigeon may circle initially to map these long infrasound waves before setting a definitive course.