Sounds and hearing are very important in the life of a bird. Not only do they use hearing to interpret the songs of their fellow birds, but also to keep in touch, warn those around them of danger, win over a mate, find their dinner, or recognize their kin. Without the ability to hear, birds would be completely lost.
Songs and Courtship:
Birds, usually males, use song to demonstrate their intelligence and endurance. They also use it to advertise their maturity. Most birds learn to sing at a young age, and some will continue learning throughout their lives (mimics.)
Birds may use sound to give out warning calls to their fellow birds, and even some mammals. Some birds have learned to use this to their advantage, sounding false alarms so that they can claim any food for themselves. Birds will give warning calls out to warn of danger or also to define their territory to other males in the area.
Some birds, like ganets, locate their young by sound alone. In rookeries made up of thousands of birds it would be easy to lose site of your young ones. Birds use a distinctive call to reconize their young. Most birds learn this call before they even hatch from their eggs! Some birds, like quail and pelicans, can make noises and communicate with their parents from inside their egg shells. Pelican chicks even tell their moms if they don't like the temperature.
Many birds, like the American Robin and the Barn Owl, rely soley on hearing to locate their prey. This means that they could be blindfolded in a pitch dark room and still find something to eat based on hearing ALONE! Some birds even have aymmetrical ears on their hears (ears are in different places) so that they have binocular hearing which pinpoints their preys location.
Interesting Bird Hearing Facts:
-Some birds have sensitive enough hearing that they can differentiate between different classical music composers (pigeons are known for this.) -Cave dwelling birds, like swiftlets, use echolocation to locate their prey. This is similar to the way that bats and dolphins hunt. -Turkeys can pinpoint sound from almost a mile away!
1)Humans hear relative pitch, meaning that they can recognize the same mealody in higher and lower octives. 2)Humans process sound bytes at about 1/20 of a second 3)Humans have symmetrical ears (same place on both sides of the body) 4)Humans have visable pinna, which they sometimes decorate with jewelry. -Humans, like other mammals, have 3 bony ossicles in their middle ear to help transmit sound to the ear drum -Humans have a coiled cochlea
1)Birds have absolute pitch, meaning that they recognize the actual note that is played and cannot distinguish pitch. 2)Birds process sound bytes at 1/200 of a second 3)Some birds have asymmetrical hearing, meaning that their ears are in different places on each side of the head. 4)Birds lack the external, visable part of the ear, called the pinna -Birds have only one bony ossicle inside of their ears -The cochlea in birds is either straight or slightly curved
Inside the Avian Ear:
Bird ears, much like human ears, are very sensitive structures. They are made up of a series of canals and tubes, lined with sensitive hairs. Much like the human ear, the avian ear is in control of the birds center of balance. The fluid inside of the semicircular canals tells the bird the orientation of its head at any given time, allowing the bird to better manuever it's surroundings.
Parts of the Avian Ear:
Auricular Feathers- The feathers surrounding the ear hold openings of the ears. These feathers help to funnel sound into the ear canal while protecting the ear from external noise pollution. Acustic Meatus- A tube which carries sound and vibration into the ear drum Tympanic Membrane- The membrane which seperates the external ear from the middle ear. Columella- The only bony ossicle located within a birds ear. It picks up vibrations and transmits them to the inner ear. Middle Ear- An air filled cavity in a birds ear that contains muscle, ligaments, the tympanic membran, the cochlear window, and the ossicle (columella.) The Cochlear Window- An opening in the medial wall of the middle ear that attaches to the cochlea. Cochlea- The part of the ear that is actually associated with hearing, this is where the vibrations are converted into nerve pulses that are sent to different parts of the body. Utrical- The larger of the two fluid filled cavities of the inner ear. It contains hairs which send signals to receptors in the brain which lets the brain know the orientation of the head. Semi-Circular Canals- The 3 fluid filled canals of the inner ear that run at right angles to one another. They also provide the brain with information about the orientation of the head. Tympanum- The actual ear drum, where sound vibrates. Saccule- A bundle of nerves that translates the movement of a birds head into something that the brain can interpret.
Where are a Birds Ears?
Although they don't have the visable pinna, a birds ears are still fairly easy to locate, if you can get close enough that is. Blowing gently on the side of a birds head while you hold it will reveal the location of the ear holes. Most birds have small feathers covering these holes in order to reduce some of the noise pollution from wind disturbance. Birds that dive, like seabirds, have hard, thick feathers covering their ear holes. This helps them keep the water pressure out of their ears while they dive down for prey.
What About the Earred Owls?
The "ears" we see on the earred owls are really just tufts of feathers made to look intimidating to other potential enemies and prey animals. They are actually not in fact ears at all.