A group of scientists from the Max Planck Institute for Ornithology have discovered that city-dwelling blackbirds use a variety of methods to ensure their songs can be heard over background noise. Like all birds that live in an urban environment, blackbirds must deal with noise pollution produced by traffic and other city noises. Most of this noise pollution is low-frequency.
By singing at high frequency, blackbirds communicate in a range of sound that can be distinguished from low frequency background noise. But that's not the whole story. Not only do blackbirds sing at a higher frequency, the physics of sound means that they sing louder at the higher pitch too. In fact, researchers have discovered that it is more the increase in volume than the increase in pitch that enables blackbirds to out-sing background noise. And in an urban environment, anything that gives a bird some of extra boost to their song is beneficial.
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