Tall tree, loud robin

Recording birdsong demands endless patience. Even if you find an environment where birds are likely to be, at the right time of year, at the right time of day, the bird itself might be too far away to hear, or obscured by some other sound.

That’s if you’re only trying to capture birdsong, though, and there’s plenty of it out there already. What makes new recordings worthwhile is that they can tell us about our environment by showing how birds interact with it. With that in mind, today’s birdsongification features the humble robin.

As much as London’s main roads are often rammed, its side streets fall very quiet during the day, so most of the mature trees on residential streets reliably host birds. The taller trees provide a sonic advantage in that songs from greater heights travel uninterrupted over larger distances—handy for announcing to other robins that this tree is occupied, thank you, by a good strong robin having a lovely day.  In a tall ash tree in Highbury this individual managed to make itself heard quite clearly, even 50 metres away from the microphone. You can really see the crystal quality of its song in this sonograph of the recording.

To make it easier to see, the sonograph has been cut as if you’re reading text, from left to right and top to bottom. You can see the incredible regularity with which the bird times its phrases, slowing down very gradually over about two minutes.

These sounds are all in the frequency range 3kHz-10kHz, or in other words, pretty squeaky—certainly far above the sound of traffic, unless anyone has squeaking breaks. That helps the birds cut through the soundscape even on a busy day. But some sounds can still interfere: the footsteps near the beginning, for example, or the car door that shuts, or really anything else close enough to be more than a background hum. Birds adapt their behaviours, including song, to thrive in urban areas—urban sparrows tend to sing at higher frequencies than their counterparts in nearby woodland habitats, for example—but there’s only so much they can do.

The most remarkable thing is that a little bird can make itself heard clearly from some distance, even in London. That doesn’t mean anything particularly profound in the grand scheme of ecology and conservation, of course, but it still feels like a pocket of hope.

Jay Richardson

by Jay Richardson
Friday 29th April 2022