Now that it seems that this long cold winter has finally broken with warmer mornings now a feature of the British landscape, many of you will have noticed how the volume and intensity of the dawn chorus has increased in the last 2 weeks. Even if you are not a birdwatcher, waking up at any time between 4am and 6am somewhere away from human noise will reward you with a cacophony of birdsong, even in the most suburban of gardens.
In the United Kingdom the peak time for the dawn chorus is generally accepted to be around the end of April and into the first week of May. However during any mild spell of weather after Christmas a dawn chorus can erupt up. Indeed this year if you can remember the first two weeks of January were unseasonably mild before the cold set in. So mild in fact that a chorus of sorts began very early in the season and featured in some newspapers, albeit with a caveat that colder weather was on the way. They weren’t wrong!!
My guess is that for many casual observers (or should that be listeners), and I was one of them until I understood, the dawn chorus is just one thing, the birds sing-a-bit around dawn and then shut up. In simplistic terms well yes that’s probably right although it often begins before dawn and ends well after, depending on season and weather. And of course the birds don’t stop singing; they’re just engaged in other activities so sing a lot less. Indeed a mistle thrush was singing well at 2pm on Friday but only before it flew off to forage.
But by mid April it really is beginning to turn the volume beyond ten and onto 11. The reason why we notice this soundscape of natural song so much at dawn is that that early in the day the countryside is generally quiet in terms of other ambient sound, there’s normally less wind and we are often ourselves attuned to noises as we wake. The birdsong is therefore especially clear at dawn and some studies have calculated that birdsong will carry 20 times as well as at noon.
Many of you with a keen ear will notice the structure of the dawn chorus individual species subtly changes through time. In essence this is related to light levels. Purists will say a dawn chorus begins half an hour before dawn and ends about 45 minutes, after dawn, but in reality it has no defined start and end times, and species do not have a set order when to begin or end. Individual groups do tend to sing in chronological order, but individual birds, the time of year, the weather and the temperature all play a role. Those a lot more informed than me could discuss the science behind this but, for this posting, I’m interested in the changes that take place for the casual listener.
To try and illustrate this I did 3 recordings over a single half hour period last weekend in Wiltshire. These were recorded in the back garden of our house, which is luckily in a very isolated part of the Wessex AONB, but even there I still had a few planes and the odd car to contend with. It’s not easy recording natural sound in Britain these days.
Blackbirds are dominant here with their wonderful fluty calls. The dawn chorus often starts with the thrush family. That’s an awful generalization but in my experience blackbirds and robins are often the first to begin calling, often well before dawn. Blackbirds, song thrush and robin are birds with relatively large eyes and can adjust well to the low light levels, eyes designed for forage in low light areas of scrub and woodlands picking through leaf litter for worms and grubs.
The blackbirds are still there, but as the light levels gradually increase some of the smaller birds begin to call, such as wrens, chiffchaffs, dunnock and later in the season migrant leaf warblers. The amount of song now increases in density. These birds, the insect feeders, dart about trees and shrubs foraging for insects so tend to have smaller eyes than the thrushes as in the canopy there is more light to find their prey.
By now the more familiar birds of our gardens are beginning to start the day, house sparrow and chaffinches, the seed eaters who are foraging for seed out in the open and generally have smaller eyes so need more light than say the thrushes before they become fully active. The blackbirds and dunnocks are still calling but certainly if you compare this recording with that made at 05.15 hrs, the sparrows dominate the chorus. Partly it has to be said because I was by the house and we have a healthy sparrow population.
These recordings above were sourced from a garden surrounded by farmland and woodland, the species therefore were those of that type of habitat. Different species would be heard in wetlands, moorlands and even open farmland (we’re surrounded by ancient woods). Again to illustrate this, this morning at 05.30hrs I recorded another dawn chorus near the Bristol Channel in Somerset. Being this close to the coast, gulls are competing with the more open farmland birds.
I hope this helped and you enjoyed this brief resume of the structure of the dawn chorus. But let us not forget that the dawn chorus - or even as some call it the birds' "hymn to the dawn" is in fact no more than a battle cry. It sounds lovely to our ears as we wallow and bathe in that emulsion of sound, but out there in our garden or field, it’s bird eat bird. Males are defending territory, looking for new territory, attracting a mate, squabbling, confronting each other and in doing so their song is their weapon of choice. Nature is tough and brutal; those with the best song, the loudest song will win and by winning the next generation is born. No room for shy violets out there, now get of my land…..!
Eventually though all that posturing and singing has to end and like a drunken man who having been thrown out of the pub finds himself at the kebab house, the birds that sang so beautifully for our ears begin to feed and have breakfast. They’ll do it all again tomorrow. Or later today! Because let’s not forget the dusk-chorus. This is audibly a lesser event but well worth listening for because much as thrushes began the day, they often end the day. I just love the blackbird’s tink tink tink alarm call as they jostle for prime roost sites. Well worth a listen in your back garden, ideally with something grape based in the hand.
In a couple of weeks it is InternationalDawn Chorus Day, on 5th May 2013 organised by Birmingham and Black Country Wildlife Trust. http://www.idcd.info/ So if you love birds, love natural sound, or just want an early walk in your local park, have a peek at this link there may be something near to you.