It may not have commercial value, but birdsong is priceless

Insect pollination is worth £136bn a year; a robin’s value is harder to quantify

Last week, I typed a phrase into Google, and got a blank. “No results found,” the search engine said, “for ‘the economic value of birdsong’.” I was minded to ask just how much warbling and twittering were worth, in monetary terms, because real cash values are now being put on much of the environment, and also because, at the start of the week, I realised that the blackbirds had started singing again. I went on a stroll up a long, tree-lined suburban road just after 5pm and walked into a birdsong torrent.

It had been caused by that most welcome phenomenon of the advancing year, the return of evenings. There don’t seem to be any evenings in November, December or January: the afternoon comes to an end and then it’s abruptly dark. But as the ends of afternoons start to lengthen, towards the middle of February, a moment arrives where the light takes on a particular still and intense quality (especially when there are clear or clearish skies). This suddenly triggers a great burst of avian vocalisation, and in leafy suburbs – where the blackbird population is far denser than in the countryside – it’s like a wind around your ears.

I find this exhilarating, not only because it is such a happy signal of the returning spring, but also because it hasn’t been there for six months. We forget how most birdsong comes to an end in high summer, probably because we are all too preoccupied with holidays to notice; but by August, nearly all species have fallen silent.

The main exception is the robin, which carries on singing all through the autumn and winter, and, in fact, is more prominent than ever because female robins sing as well as the males. If you hear a bird singing in December, there’s a 10-to-one chance it’s a robin (unless the song has a trill in the middle of it, in which case it’s probably a wren). It’s a sort of twittering warble, in short phrases which sound rather wistful, and it’s pleasant enough, but it’s not a patch on the serene, peaceful, loud and wonderfully musical song that male blackbirds produce. When they’re all doing it together, as in the evening light of last week, or in the dawn chorus, it can be truly heart-stopping, especially if you haven’t heard it for half a year (and the song thrushes are even better).

So what’s it worth? I asked and got no reply. I asked because many aspects of the natural world are now being given real financial value, to represent the services they perform for us, the most obvious being the pollination of crops by insects. Google that, and you can find various estimates for its worth, a common one being that across the world, insect pollination is worth £136bn annually to human society (you can make an estimate by working out how much it would cost to replace what insects do by other means).

There are many such valuations now, all in millions if not billions of dollars, for aspects of nature such as coral reefs (which provide fish and tourism), or mangrove swamps (which protect tropical coastlines), or rainforests (which give us all sorts of benefits, from oxygen to drugs). They form the basis of the new science of ecosystem services, which is widely seen as the great hope for saving the planet – once we know the true worth of what nature does for us, we’ll stop trashing it. Won’t we?

The trouble is, the use of ecosystem services as a defence of nature is extremely selective – you accord worth only to those parts of it you can put a direct monetary value on. But if we take a phenomenon such as birdsong, and find we can put no monetary value on it, is it then worth nothing?

I can only say it is worth an awful lot to me, and I have no doubt it is worth an awful lot to many other people as well. Britain’s most famous songbird of all is the nightingale, which since 1970 has declined by a staggering 90 per cent. Its best remaining site is a woodland in Kent, Lodge Hill, which is now threatened with obliteration by a housing development. Many people are trying to save it, even though no one can say that it is worth £10m a year, or anything whatsoever. But I think it’s worth saving.

The science of ecosystem services offers great hope for defending the natural world, but we should not forget the gaps in it, which are significant.

We should remember that there are other huge worths in nature, which do not have dollar or pound signs attached.