Have you ever noticed that winter sounds different from any other season? In winter, sound has its own unique quality, and its character changes throughout the season.
Hi, this is Iain MacLeod from New Hampshire Audubon, bringing you Something Wild.
Have you ever noticed that winter sounds different from any other season? In winter, sound has its own unique quality, and its character changes throughout the season.
Before the snow arrives, the ground is hard, and sound carries through the air loudly and clearly. White-breasted nuthatches calling in a neighbor?s yard sound as if they are at your house. The sharp call of the hairy woodpecker pierces the air. The sounds are clearer because the frozen ground reflects sound in the same way that sound carries over water.
Winter?s sounds change again once the snow arrives. As a child, I could tell it had snowed before I had opened my eyes in the morning. The subtle muffling of sound was enough to let me know that I might not have to go to school that day!
Why does the sound change? The deep snows of winter absorb the higher frequencies of sound, those that humans hear well. When the ground is hard and bare, all sound waves, both high and low, are reflected back into the air. They carry farther and are easier to distinguish, because we hear both the lower and higher frequencies.
Birds use these frequencies better than people. The deep hooting of a great horned owl can carry for more than a mile in the forest because low-frequency waves travel around objects. Many birds use high-pitched alarm calls when danger is spotted because predators have difficulty locating the exact source of high-frequency sound. These alarm calls do not travel through the woods as well as low-frequency sounds, so birds a safe distance away will not be unnecessarily panicked.
So? this winter, pay attention to the way sound travels. Can you notice the difference that snow makes on the bare frozen ground?
Something Wild is a joint production of New Hampshire Audubon, New Hampshire Public Radio, and the Society for the Protection of New Hampshire Forests.
For Something Wild, I?m Iain MacLeod.
If you have a natural history question that you would like answered on Something Wild, email us at somethingwild@nhpr.org.
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