Blogs / Cosmic Variance

The almost always excellent science presenter, Quentin Cooper hosted another programme in the series called The Material World, on BBC’s Radio 4 today. (Do keep an eye on this show, as it often has very good programmes.)

The second half of this week’s programme is about birdsong. (There was some nice discussion of using physics in design of better modern buildings, which was also interesting, but I was more into the birds.) Here’s the teaser for the bird part of the program:

Whether it’s a rude awakening by the dawn chorus, or the accompaniment to a gentle stroll through the countryside, nature’s music – birdsong – is all around us.

But why do they do it? Is song the avian equivalent of human language?

This week Quentin Cooper is joined by Dr Rob Thomas from Cardiff University Biosciences department and Peter Slater, Professor of Natural History at the University of St Andrews. They’ll be letting us into the secrets of the bird’s world, from virtuoso performances in Central America, to the dawn chorus tactics of the robins in our gardens.

It was a lovely programme, and I hope you’ll find a bit of time to listen to it if interested. The link is available from the programme’s homepage, where it says “listen again”. Be warned (as usual) that the BBC will overwrite this programme by next week with next week’s episode, so get to it soon.

There’s the lovely image, described by one of the guests, of territorial songbirds (a type of wren, if I recall correctly) that get together and sing an agressive chorus at an intruder. As part of a study, they played the sounds (a rival song) of an intruder from a speaker, and the birds whose territory it was showed up an just blasted away in unison at the speakers…. I love that image.

There’s a lot of discussion about the phenomenon of dueting in birdsong, and why it is less common in northern latitudes. Daylength seems to be very important, but I’ll let you listen to the programme to hear more.

As an example of one of the many remarkable things I learned in this 15 minutes of listening was a theory (still being investigated) about the reason for phenomenon of the dawn chorus, where there is a cacophany of birds singing at around dawn, particularly in some colder or more temperate climates. It is believed (according to one of the guests on the programme) that at least some of the reason for this phenomenon is budget surpluses. The song birds stock up quite a bit on food to store more fat reserves the day before, since they can lose 10-15% of their body weight overnight if it gets cold, and this can cause them to die of starvation. They don’t know in advance how cold it will be, so they budget for the worst case scenario. Most nights are not all that bad and so when the morning comes they now want to get rid of all that extra energy they’d stored as fat, since it will slow them down during the day. So they sing like billy-o at the beginning of the day!

-cvj