Author: -. Subject: -. Keywords: -. Creation Date: -. Modification Date: -. Creator: -. PDF Producer: -. PDF Version: -. Page Count: -. Page Size: -. Fast Web View: -. Preparing document for printing…. Tab will move on to the next part of the site rather than go through menu items. Photo by Glenn P. Birds have a keen sense of hearing, but have you ever wondered where their ears are?
Birds do have ears, but not in the conventional sense. Like humans, they are equipped with an outer ear, middle ear and an inner ear. Instead, they have funnel-shaped ear openings located on both sides of their heads that are usually positioned just behind and slightly below the eyes, according to BirdNote.
These openings are covered with specialized soft feathers known as auriculars. The auriculars extend back and down from the eye and serve to protect the ears while also cutting down on wind noise. For mammals, external ear structures are critical for guiding sound into the ear canal and determining where a sound originates. Naturally, for creatures who move in a fundamentally more three dimensional universe than we do, a good sense of balance is very important.
Quail chicks use calls to communicate with each other and their mother from inside their eggs. In this way they are able to synchronise their hatching so that they all emerge from the eggs within the space of a couple of hours. Pelican chicks tell their mum if they are too hot or cold from inside the eggs. Chicks also listen to their parents while inside the eggs. This way they come to recognise their parents, even before emerging from the eggs. Some birds, such as Mallards, have special maternal calls that they give while incubating the eggs — so that after hatching the mother only has to give this call, to have the chicks rush to her for protection.
A deaf female turkey is unable to recognise her own chicks and chickens cannot recognise silenced chicks with a bell jar over them. Experiments have also shown that, in colony nesting birds at least, young birds can recognise their own parents by their calls alone — though they all sound the same to us. In Herring Gulls, about 5 days pass before this recognition takes place, while Kittiwakes take up to 5 weeks for recognition to register.
Birds also distinguish their mates by call. Gannets are colony nesting birds and a nesting site can have thousands of birds coming and going in a noisy melee that would befuddle a human listener. Sounds can be created by stamping, as in Coots, or by clacking the mandibles together as in Frigate birds, Albatrosses and Storks.
Birds also use their wings to create sounds, simply by clapping them together as the wood pigeon, or by having modified feathers which vibrate at a set frequency when exposed. Snipe use this during courting. Two feathers on either side of the tail vibrate as the bird falls out of the sky.
Perhaps the best known of these percussive sounds is the drumming of woodpeckers. Each woodpecker, in those species tested, has its own drumming pattern so male and female birds can easily recognise each other while they are out foraging. Perhaps the most unusual however is the Palm Cockatoo, which makes drumsticks from twigs and beats them against a hollow log in time with a pirouette during courtship!
Several species of cave dwelling birds use echolocation, similar to bats, to detect objects around them in the dark. Swiftlets from S. Asia — also known because some of them produce the nests used in making bird-nest soup — use sounds with a frequency between 4. Oilbirds in South America also nest in caves and use sounds in a range between 1.
Unlike the Swiftlets, Oilbirds are nocturnal, but they do not use their echolocation outside of the cave. The sounds both these species use are audible to the human ear… and sounds caused by a flock disturbed by a human intruder in their nesting caves have lead to many tales of devils and demons.
The echolocation of both these species is considerably less efficient than that of bats — because the sounds are lower and therefore have longer wavelengths. This means that they cannot distinguish smaller objects.
Oilbirds cannot, apparently, detect anything smaller than about 15cm diameter while Swiftlets have a lower size limit of about 6 cms diameter. Located within the ear of birds is a small, poorly studied organ known as the paratympnaic organ. It was discovered for humanity by Giovanni Vitali in Vitali continued to study the organ until and since then a mere 27 papers have been published on it. According to Bartheld and Giannessi, who published a review of the Paratympanic Organ in its function is still not fully understood, or at least has not been fully proven.
However, because of its position and structure, including the nerve connections, it is believed that it serves the bird as a barometer and altimeter by sensing changes in air pressure.
The PTO is located in the medial wall of the tympanic cavity, above the opening of the Eustachian tube, adjacent to the stapedial artery and auricular vein, and dorsolateral to the columella in the avian middle ear. This tissue that makes up the PTO contains a elongated vesicle fluid filled bladder.
The lumen central area of this vesicle is filled with a mucous, gelatinous fluid, and its medial side situated near the midline contains a sensory epithelium covered by a gelatinous cupula small dome. The sensory cells have been identified as type-II hair cells by electron microscopy each with 40— stereocilia and one kinocilium that extend into the fluid-filled lumen.
This is a number that is comparable with the number of hair cells in the spiracular sense organ of some cartilaginous fishes and also in mammalian vestibular end organs.
Remember, for information on bird calls and songs see Bird Songs. Are there any studies on the level of decibels that damage hearing of birds? How do some birds live at and visit airports? Would a loud train going by decibels cause damage to the ear of a bird?
Hello: a landowner near where I live allows me to go in to his forest from October to March of each year to set up a tube feeder and a suet cage for the local birds.
The feeders are visited by nuthatches, bluejays, cardinals, juncos and chickadees. When I enter the forest I make the same repetitive call to the birds to let them know I am there. Question: can any of the birds I mentioned remember my call and for how long days weeks ,.
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