Decoding the secret language of birds — new film Birdsong is endearing and enlightening

Seán Ronayne who grew up in Cobh, County Cork, went on a mission to record the vocalisations of every bird species in Ireland

Birdsong: For birdwatchers, the ability to identify the calls of various species, to ‘decode’ the secret language of birds, is key to identifying species and understanding behaviour

Evolution is a mysterious thing. Their oldest known bird fossil is 150 million years old, and their various shapes and forms have gone through a mammoth amount of fine-tuning since then. From the fossil record, ornithologists have a reasonable understanding of how they evolved, beginning as dinosaurs, developing the ability for flight, a full covering of feathers, specialist bills, and a syrinx — the apparatus that enables them to sing so spectacularly. Gradually, birds have become the tuneful, feathered beings we so love, with an estimated 10,000 species in existence around the globe — each specialised to occupy a specific ecological niche.

But the evolution of their voices is something altogether more difficult to trace back in time. While scientists have discovered a great deal about the evolution of wings in birds, for example, very little is understood about the origin of what is perhaps one of the most conspicuous characteristics of living birds — their songs. Bird calls and songs leave no material trace in the fossil record, though the evolution of the syrinx, the organ through which their complex vocalisations are made, is being studied.

What we do know, however, is that each bird species has its own suite of unique sounds. There are contact calls and alarm calls: complex melodies sung to impress potential mates and maintain pair bonds during courtship; and territorial tunes. Each sound has its own purpose and is used in very specific circumstances. There are birds that mimic (starlings, jays and parrots, for example); birds that laugh (Leach’s petrel); and birds that can sing complex combinations of sound for half an hour while barely repeating a phrase (skylark).

For most people, birdsong is a nice thing to be noticed and appreciated from time to time, but to a novice, the sounds meld together and don’t mean much. For birdwatchers, the ability to identify the calls of various species, to ‘decode’ the secret language of birds, is key to identifying species and understanding behaviour. For ornithologist Seán Ronayne, the language of birds permeates his life. It is an obsession, a source of joy, and one of the prime ways in which he relates to the living world.

Soon our Swallows will be back! It always amazes me to look at these and think that not too long before it has seen me, it has been sweeping insects from the African savannahs, sharing space with lions and giraffes. This is the sound of our summer, & it's only around the corner! pic.twitter.com/f8ONMu5lh3

— Irish Wildlife Sounds (Seán Ronayne) (@SoundsIrish) February 25, 2024

Seán’s mother tells how, as a toddler growing up in Cobh in County Cork, Seán was always watching birds from the kitchen window, and how his father used to take him out in the pram and mimic the calls of different birds to him. So to Seán, birdsong is like a second language, spoken everywhere, with hundreds of dialects and nuances, many of which he has learned to recognise. When I spent an afternoon in the woods with him recently, he described how the sounds of nature take priority in his brain, which can get often get him in trouble when in the midst of human conversations.

Seán Ronayne has recorded Irish birds, mammals, fish "and all else nature". Picture: @SoundsIrish

Seán’s interest in recording birdsong began while living in Barcelona during Covid pandemic lockdowns. He adapted some basic sound recording equipment with a jug and some cling film so he could leave it out overnight on the roof of his apartment block. That was when he discovered the wondrous world of nocturnal calls, as he listened back in astonishment to recordings of flamingos, night herons, bee-eaters, and other exotic species flying over the city at night.

He has trained himself to identify the visual representation of each species vocalisations by scanning spectrograms, so a sound recording made over a whole night or even several days can be assessed for the characteristic shapes in the soundwaves that each bird species produces (also known as a sonograph). This is how sound recordings for nighttime surveys on sites for proposed windfarm developments, for example, can be assessed for the presence of nocturnal flightpaths that would otherwise go undetected.

BIRDSONG is a 52-minute documentary film directed by Kathleen Harris and produced by Ross Whitaker and Aideen O’Sullivan for True Films

In 2020, upon moving home to Cork, Seán began on a mission to record the vocalisations of every bird species in Ireland. He began with the easy songbirds: tuneful blackbirds; cheerful sounding robins; earnest song thrushes; clear singing wrens; masterful chaffinches; hedge dwelling dunnocks; erratic great tits; and other staples of Irelands singing birds. When out walking his dog in the woodlands around Fota Island, jays barked at him from treetops, triggering an interest in jays' aptitude for mimicry. More challenging recordings to get were the elusive species such as hen harrier and red grouse, which are not at all common and live in remote, mountainous locations.

These adventures have been documented in a new film, Birdsong which premièred as part of the Dublin International Film Festival last week. Skilfully directed by Kathleen Harris, this visually stunning film follows Seán’s quest around some of the most beautiful parts of Ireland. Because Seán has been keen to record each species without the presence of anthropogenic noise, he travels to remote locations to get good recordings. Thus the film follows him at dawn through grasslands and hazel woods in the Burren in County Clare and across the sea-swept Tory Island off the coast of County Donegal, one of the last corncrake strongholds. Seeing a male corncrake tilting back his head to utter the rasping, comb-like call is a thrill to watch. Throughout the film, Seán’s fascination with birdsong is both endearing and enlightening. Joy and awe are threaded with poignant knowledge that many of the birds encountered along the way are red- or amber-listed birds of conservation concern.

Particularly spectacular are the scenes on the Skellig Islands where there are burrow nesting puffins and shearwaters too, ambling over pink thrift-covered turf of the islands. Sean's wife accompanies him on this, and many other trips, and the pair are in awe at the constant cacophony of calls from the thousands of gannets, guillemots and kittiwakes crowding the ledges of sea cliffs there. Alba’s novice interest acts to prompt accessible explanations from Seán about what we are listening to and seeing.