Birdsong is no echo of the past

I LED a dawn chorus outing last weekend. The venue was a forest with exotic trees and shrubs under the cliffs on the hill of Howth.

There’s a large dolmen there. I told the assembled group that the builders who hauled the huge stones into place 4,000 ago, had awakened to the sounds we were hearing that morning. But had they? The bird community has changed over the millennia. There were no magpies, pheasants or collared doves in Ireland long ago. Mistle thrushes, reed warblers and siskins may also be recent arrivals, so some of today’s most vocal birds would not have been around. The drumming of great spotted woodpeckers, the calls of large birds of prey, and even the loud clucking of capercaillies, could have been familiar to the dolmen builders.

Our garden bird species frequented the fringes of woodland long ago but are their songs the same as those of their ancestors? The language the dolmen builders spoke would be incomprehensible to us. Is the same true of bird “languages”? Are avian musical scores fixed and immutable like great classical masterpieces? Or is birdsong more like jazz, with performers improvising continually, allowing the music to change and evolve with the generations?