Why am I in a field with 20 pensioners, all of us going brr, brr, brr, brr brrrrrrrrrr in unison? What a vision is this cagouled collective of hip replacements and walking sticks moving in unison through the church meadow making bizarre sounds.
Now a chit, chat, chat, chit, chit chat sound, then an extremely rare spiggedly, wiggedly, spiggedly, wiggedly. It's like a mass geriatric break-out from the lunatic asylum.
And I, a little red-faced, am in the middle of this school of spritely souls as it darts hither and yon from brook to copse and back again. Every now and again, the leader stops and bids the rest to listen. We do so and, yes, it is possible to hear a different sound. A chew, chew, chew, chew in rapid time.
Short seconds later, the group is chew, chewing for all its worth, to the delight of the leader, the man they simply call John.
Look, I won't say that I was chew, chewing. You see, it was too early in the day and the embarrassment was intense.
Not one to run with the crowd, I wasn't sure I wanted to be told to chew, chew in time with everyone else. It wasn't even my idea to be in that ruddy meadow on a Saturday morning with the cast of One Foot in the Grave.
A friend and I have embarked on a search for stress-busting ways to spend some of the weekend, to struggle free from The Man's iron grip on our shoulders during the rest of the week.
We have already become quite familiar, walking along the estuary, binoculars in hand, misidentifying harbour birds.
The old Clash concert-going me has long since been buried six feet under the rubble of my own disbelief.
But now my friend was suggesting something on an altogether higher plane. A morning of birdsong rambling with a proper expert and all.
I said yes one Saturday evening after too many bottles of Budvar, because I wanted to shock my kids with how square I'd become, a post-modernist statement, if you like. I'd no intention of actually going.
Fast-forward to last weekend and John is telling us we will hear up to 20 different songs in this one patch of scrub. I am the youngest in the party. One woman tells us she is 93. John leads us to the edge of a hedgerow. My friend and I loiter at the back, the class ne'er-do-wells. Shush, John suddenly says. Can you hear?
Then he does it. Makes a crazy noise with his mouth that seems to say chiff, chiff, chat, chiff, chiff, chat. Then everyone's at it. Making the same noise.
It's a Chiff Chaff cries our 93-year-old, naming the first warbler of the day. The little blighter can't be that happy with his unimaginative phonetic name.
So this is to be the terrible pattern. Not only will we have to strain our ears to distinguish one sound out of the cacophony, we will then have to mimic it en masse, like a murmuration of madmen.
These people have been before and understand what's expected of them. They do the wren, the robin (hugely complex, by the way), the long-tailed tit and, finally, the greenfinch, the brrr, brrr of the first sentence.
At first, I refuse to get involved, but as time flows, the pastoral scene seeps into the soul and the knots and tensions of the week untangle, I look around at my half-witted, but joyous new friends and decide I, too, want to be like them.
My pal and I are soon a pair of great tits, cooing in unison. We receive beatific smiles back from the rest of John's cult, now we are signed-up members. We even cup our ears in the direction of specific sounds, a tell-tale sign of expertise. Our group is as one.
How we laugh when one of us mixes up a white throat with a black cap and politely hurrah when another harks a willow warbler without John's help. We all seek his approval.
Towards the end, I find myself moving out of my own body, listening to myself chip, chooee, chaaooo (the chaffinch, if you must know) to my heart's content.
At the end, my friend and I have to walk home the same way we have just been and the birds are still at it.
Do you recognise any of them, I ask guiltily. Nope, he confesses. We say no more, but agree to come back for revision next week.