Song of the Reed: Swallowtail review – Mark Rylance and Sophie Okonedo shine in hyped eco drama

Casting stage and screen stars in a radio play brings gain and loss. The positive is publicity: Song of the Reed: Swallowtail – the first of four dramas set and recorded on a nature reserve in each season of the year – has had so many trails that audiences may have assumed it to be a TV show, rather than that BBC Radio 4 was celebrating having nabbed Mark Rylance and Sophie Okonedo.

The negative of famous faces on the wireless is that half of their recognisability becomes irrelevant. But no one becomes a great actor without an outstanding larynx, and Rylance and Okonedo clearly enjoy characterisation through sound alone.

Okonedo is Liv, a young woman whose father – Max, a star naturalist TV presenter and author – has recently died and left her Fleggwick, the wetlands reserve he made his home and work. Rylance’s long-serving warden, Ian, could doubtless identify each of the “10,000 species” on these fens.

Radio frees actors from their bodies. The age gap between the actors is eight years but on air it might be two decades or more. His slow, gravelly, watchful tone and her brisk, light delivery, with some spikes of pain, are a lovely duet, dramatising the essential pessimism and optimism of warden and owner and hinting at dissonances and harmonies in their past that the next plays will surely explore.

It helps that listeners are liberated from the usual sense that the sound of scrunched leaves is likely to be rustled plastic bags, and that bird noise was piped in from a sound effects tape previously heard on The Archers. Location recording at the RSPB reserve at Strumpshaw Fen in Norfolk (director: Boz Temple-Morris, sound design: Alisdair McGregor) makes this a naturalistic drama in which the evocative background sounds of walking, water, wind, and wildlifereally take you there.

Steve Waters’ script is packed with background. On the day of our first visit, a manager from WildScapes has come to see whether Fleggwick would fit its portfolio of nature trail tourist attractions, aimed, as Ian puts it, at “yummy mummies with lattes in their keep-cups”.

Waters has taught and written books about the history of drama, and Song of the Reed feels knowingly Chekhovian. Liv’s burden of the nature reserve is a version of Madame Ranevskaya’s bankrupt family estate in The Cherry Orchard, and the swallowtail butterfly Ian hopes to tempt back is a (probably) luckier metaphor than the shot and stuffed bird in The Seagull.

Waters had a theatre hit with The Contingency Plan, linked dramas about the climate emergency. That concern continues here, although Fleggwick also buzzes with many other political ideas, not least that birds and butterflies are bold migrants, crossing borders freely.

Ian, revealingly, is keener to nurture the native “Britannicus” genus of swallowtail than the more numerous European kind. The counterview that nature is “heedless of nation” is represented by another emblematic pilgrim to the fens, Sadegh (Zaydun Khalaf), an Iraqi expert on wetlands, who had sought Max’s advice on restoring his nation’s marshes from their damage by Saddam Hussein’s regime. As Max – a powerful off-air presence – suffered damage to his reputation from as-yet-unspecified public remarks, and a volunteer has just started work who identifies as non-binary, the playwright has skilfully created in Fleggwick an ecosystem in which many of today’s dominant evolutionary views can thrive.

It’s common in drama to talk about the location becoming a character, but the aptly named Waters takes this literally: Christine Kavanagh plays the Voice of the Reed, delivering lines about the weather and the wildlife, sometimes in rhyme.

But that distracts from the emotional and aural realism of everything else. In the age of binge fiction, there’s something bold but frustrating about a project designed to drop an episode every quarter. However, the first instalment contained enough ideas to make the rest worth waiting for.