How well can your bird hear?
Have you ever wondered how well your bird can hear? How can we test what a bird can and can’t hear? Birds have fascinating hearing abilities though they differ from ours in some intriguing ways. To test a birds hearing, scientists train captive birds to peck at a lever when they hear a sound. They then play tones at different volumes and frequencies, determining the quietest sound each bird can detect at each frequency. Alternatively, researchers can measure auditory responses directly using electrodes on a bird’s auditory brain stem, recording activity as different tones are played.
We often assume that the senses of birds including hearing are superior to that of humans, but is this actually the case? Looking at the frequencies that birds can detect compared to humans is where things get interesting. The frequency of sounds is measured in Hertz, abbreviated to Hz. In terms of frequency range, most humans can hear sounds between 20 Hz and 20,000 Hz. Birds, however are most sensitive to sounds between 1,000 Hz and 5,000 Hz, with hearing dropping off at frequencies outside this range. For example, no bird tested, so far, can detect sounds higher than 15,000 Hz. In general a birds ability to hear very high and very low frequency sounds is poorer than that of most humans!
It’s not just about frequencies. Birds excel in other aspects of hearing that far exceed those of humans For example, studies show that Budgerigars and Zebra Finches, are about three times better than humans at recognising subtle differences in acoustically complex sounds. This suggests that birds listening to the vocalisations of other birds are able to distinguish small differences and rapid changes that are inaudible to humans.
So what does this mean? When we wake up in the morning and you hear birdsong, we tend to think that we can distinguish all the subtle notes, but in reality we do not have a clue that there is a world of communication happening around us every day, of which we can only catch a glimpse.
