I've just come in from the garden, where I take 10 minutes time out early each morning just to get a bit of a nature fix to greet the day. Although there is so much for the eye to see at this time of year, with unfurling flowers and burgeoning foliage, it was the sounds of the garden that clamoured for my attention today.

From every every tree, every shrub, there seemed to be wonderful singing of some sort. A tweeting and a twittering and a burbling and a babbling. It was a joyous chorus, and if I get a chance to go back into the garden this evening I know some of them will still be at it, such is their urge to sing and be heard.

But how do you tell one singer from another? It can seem quite a challenge.

Well, although I'm the world's worst salesman, I will allow myself to explain that this week my new RSPB book/CD was released, The RSPB Guide to Birdsong. (Well, there aren't many times in one's life you can say you have a new book out, unless you're Jeffrey Archer or Barbara Cartland!).

Almost four years in the making, I've been trundling across the UK (when my RSPB day-job and garden have allowed), recording birdsounds and trying to devise methods that will make it easier for people to learn and appreciate the different sounds.

The great thing is that gardens are no bad place to start to get to grips with birdsounds. Not only are there a dozen or so starter-species to test yourself with, but actually some of the garden songs are among the more difficult to learn. Maybe you have already mastered them, in which case good going! (Some people are naturals, I find - they have 'the ear'). But for others, telling apart birds such as Robin, Wren, Blackbird and Dunnock can seem an impossible task.

So here is a quick guide to three species that were singing their hearts out in my garden this morning, and quite possibly were doing the same in yours, too.

First, the Dunnock. Each song verse is typically two to four seconds long, and is a rather hurried and anonymous and little ditty. It shuttles along in a hurried way, wandering up and down but all rather samey and squeaky - 'diddly diddly diddly diddly'. Listen carefully and you will hear that each verse is actually the same - or very similar - to the one before.

In contrast, the Robin sings a more laid-back song. Every verse is different. Each tends to be a little shorter than that of the Dunnock, just one to three seconds long, and they include long, still notes with more gurgling sections. The effect is very watery - this is a song like a mountain stream, sometimes in still pools, sometimes rippling and tumbling.

My third soloist was the Wren. Now here's a bird that knows how to sing an epic. Each song verse is typically four to six seconds long, and it packs in over a hundred notes in that time. It is loud - unbelievably loud for such a small bird. Unlike the samey-samey Dunnock, each verse is made up of distinct sections, including some rapid-fire trills and rattles.

In the book, you get to hear the sounds on the CD or digital download, there is a narration to guide you (we couldn't afford Stephen Fry so you get me instead, sorry), and it all runs in tandem with the book, so you can learn things at your own pace much as you might get to grips with a foriegn language.

Now is the perfect time to really immerse yourself in birdsong, so I hope you too get chance to get out into your garden or local greenspace, close your eyes and open your ears. It is part of what makes a garden so special.

And just in case you have missed the news, the RSPB is also releasing a single of pure birdsong called 'Let Nature Sing', on pre-order now and full release on 26 April, with the idea of getting nature into the charts. It is a celebration of its beauty but also a wake-up call to make everyone aware that we are losing so much nature from our world and we can't let it happen. The single costs about one pound (depending on which music retailer you download it from) - although it wasn't devised a 'charity single', a record has to have a minimum price to be eligible for the charts, and any proceeds will go into RSPB's nature reserves.

Over the next few weeks, we'll be telling the story of how I worked with professional musicians and producers to create the single, but for now I'd love you to help us get it into the charts and hence put nature into the public domain in a more powerful way than any advertising campaign or press release.