With winter almost behind us, thoughts are turning to sunny spring days with the sound of birdsong and the buzzing of bees. As the chack-chack of winter fieldfares fades and our blackbirds and robins burst into song, what better song to listen out for than the onomatopoeic voice of chiffchaffs?

I love the onset of birdsong as spring gets closer. On sunny winter days great tits begin their 'teach-er teach-er' squeaky wheelbarrow calls and the song of blackbirds fill the air as dusk falls. But it's not until I hear a chiffchaff that I feel spring wash over me.

These diminutive birds usually fly south for winter – to southern Europe or North Africa – but in recent years, as our winters have got milder, more and more have hung around in the UK. Chiffchaffs are insect eaters so a mild winter can see many more insects out and about; perfect for chiffchaffs and other birds. Over-wintering birds like chiffchaffs are often found in coastal areas or in places with good places to snuggle down out of the weather and a high chance of insects; thick hedges, dense scrub and even sewage treatment works are popular. It’s a risky strategy – if the weather turns, a bird could easily get caught out and it could all be over.

The question is whether the chiffchaffs that spend winter with us are the same individuals that were here in the summer. The jury is currently out. If blackcaps are anything to go by, ‘our’ summer birds head south and are replaced by birds from further north and east. Chiffchaffs usually start arriving in the UK from March so do listen out for them if you're out and about.

Spring is a time of reawakening. On a lunchtime walk around the nature trail at our HQ, Lower Smite Farm, we hear chiffchaffs singing from the trees, watch early bees buzzing towards pollen-laden catkins, catch sight of brimstone butterflies dashing past and follow the progress of frogspawn in our ponds. The transformation is taking place where you are too so keep an eye on what’s happening in the garden, have a stroll in your local park and note the changes taking place, notice what’s flowering in the hedges and on the verges as you pass.  Spring is finally on its way!