I admit it. My hearing isn’t what it used to be. Of course, my mother says that as a child, my hearing was pretty selective anyway, but that implies a will, not my body’s wanton disregard for my desire to hear bird songs.
Do birds lose their hearing as they get older? “Older” in the avian world isn’t very old, so perhaps there’s no time to lose it.
Birds born deaf or who lose their hearing have a major problem. Calls and songs are keys in gaining territory, attracting a mate, staying in touch with the flock, distinguishing young and hearing another bird call out a warning.
Bird song is not a totally instinctive trait, although birds certainly learn their species’ songs. But a bird that is deaf does not sing the right song, and if it hears the song before it goes deaf, it sings a distorted version.
While human and Vulcan ears are prominently displayed, some animals’ ears are not. Birds don’t appear to have ears, but pull aside a few feathers and large ear holes are evident.
Birds manage without external ears, which would interfere with flight dynamics and create a roar as the air rushed past. In most birds, specialized auricular feathers protect the opening but funnel sounds toward it.
Many owl species have large ear flaps that resemble human ears. Owls’ ears are asymmetrical to help localize sound. They are the only vertebrates to have that design.
It’s a nearly perfect detection device. Owls can even change the position of their auricular feathers. Nocturnal hunters have far more hearing receptors in their brains than their daytime-hunting counterparts.
Strangely enough, a woodcock’s ears are located ahead of its large eyes, between the eye sockets and the base of its bill.
Go figure.
Humans and birds recognize sound differently. We have relative pitch. We can hear a song in one octave today and then hear the same song in a different octave a week later and recognize it.
Birds recognize sounds in something that’s close to absolute pitch, meaning that if they recognize a bird song in one octave, they won’t recognize it in another.
But birds are experts at hearing and recognizing the timbre, or color, of a note. Timbre (“TAM-ber”) is everything about the sound that doesn’t have to do with a note’s loudness or length. It’s what allows us to recognize two different instruments playing the same note.
Birds hear shorter notes than we do. Our ears and brain can’t process some of the bird notes fast enough. If we hear one bird note, a bird might hear several notes since it can distinguish sounds that are as little as six-tenths of a millisecond apart.
Zounds.
But while birds as a whole are more sensitive to intensity and have a comparable frequency range as humans, a single species hears in a narrower band of frequencies than humans. The frequencies that are audible differ among species.
Generally, birds have the most sensitivity to sounds between 1,000 and 5,000 megahertz, roughly the top two octaves on a piano.
Any one species doesn’t hear everything humans hear, although rock doves and chickens can hear lower sounds than we can. Woodpeckers hear sounds at very low frequencies, probably being able to detect insects moving in a dead or dying tree, even though humans could not hear the sounds without a stethoscope.
My hearing should be so good.
Why not? Here’s a chance to get out, work out and help out at the same time. The Stilly-Snohomish Fisheries Enhancement Task Force, the Snohomish County Marine Resources Council and WSU Beach Watchers are holding a volunteer cleanup 10 a.m. to 1 p.m. Aug. 26 on the North Fork Stillaguamish River.
Meet at the Big Rock-Blue Stilly state Fish and Wildlife Department boat put-in site near Arlington, where assignments will be made. To sign up, or for more information, call Kristin Marshall at 425-252-6686.
Columnist Sharon Wootton can be reached at 360-468-3964 or www.songandword.com.
Talk to us
> Give us your news tips.
> Send us a letter to the editor.
> More Herald contact information.
