This is the Guardian. In the middle of a mossy wood in Cambridgeshire, you're likely to find a man who knows a lot about a certain type of bird.

He is Europe's leading expert on marshtits.

There's one other man in Sweden who possibly

loves marshtits as much as rich.

Richard Broughton, who works at the UK Centre for Ecology and Hydrology,

spends his time twice a year in monks wood, strolling through the gnarled roots and trees, watching the lives and goings on of the marsh tips.

It's a very unticky setup. He literally walks through the wood with a Nokia brick phone and he plays alarm calls from

a marsh tip that was alive 20 years ago on the Nokia.

Here we're coming now. It's going to come to.

It's probably going to come from the side.

It's very nosy neighbor vibes.

Like, Rich knows everything about these birds.

Their life histories, their partners, who they don't get on with,

whether they're shy or outgoing. But Richard is doing much more than getting the latest

marsh-tip gossip. He's charting the population of this species as the wood, which was

once buzzing with their song, Falls Quiet. So why are the numbers of marsh tits and other woodland birds dwindling?

And what can the study of environmental sounds, a science called biophony,

tell us about the changes in the

ecologies around us. From the Guardian, I'm Madeline Finley, and this is

science weekly. Finley and this is Science Weekly.

Phoebe Weston, you're a biodiversity reporter at The Guardian,

and you went to Monkswood in Cambridgeshire to speak to Richard Broughton and find

...