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Pests, Petrichor and Geosmin

As I loaded my hunting kit into the car I could barely smell it. When I climbed out of the car with a verdant wood on one side and a ploughed field on the other, the scent was overwhelming. It lifted my spirit. Made me feel glad to be alive. A distinct odour adored by anyone who hunts, farms or simply enjoys the great outdoors. Petrichor, released into the air following last nights much longed-for rain. It was also an indicator of ideal stalking conditions. More on this later.

I looked out across the lush water meadows bordering the Wensum river and I was delighted to see cattle there once again. The incumbent tenant farmer had sold his herd but another farmer has stepped in to lease the meadows. On my drive into the estate I’d seen the ‘potato boys’ at work. Half a dozen machines, a co-operative, pouring seed potatoes into the carefully ploughed trenches, covering them and fertilising the soil behind. All this activity would work to mine and the deerstalkers advantage. With such industry in the fields, the wildlife would be in the sanctuary of copse and wood.

A clamour to my left made me raise my head to watch as a pair of greylag geese flew low around the edge of the wood like a pair of the F35 Lightning fighter planes practising (for what seems inevitable) in local skies lately. The geese were almost as noisy. Before opening the gate to the wood I gave the rusty latch a liberal dose of WD40. Silence isn’t golden when hunting. It’s essential. The squirrel, the fox, the hare and the deer soon associate the slam of a car door or the squeak of a hinge with imminent danger. Did you notice I didn’t say rabbit? I haven’t shot (nor seen) a rabbit on this estate for three years now. I’ve occasionally found rabbit ‘currants’ and suspect any feeding activity is purely nocturnal. Any ‘scutties’ that survive RHVD2 though are unlikely to survive predation of nursery stops by the myriad badgers that undermine this landscape. This place would be a perfect experimental site for species balancing. Proper conservation – not the free-for-all that rewilders advocate. Thin out the badgers and watch the return of ground-nesting birds and small mammals. God knows? We might even see a hedgehog for the first time in my fifteen years here too!

Inside the wood, the petrichor was intense. It is a phenomenon caused when light raindrops hit dry soil. Years ago it was known as argillaceous odour. Drought struck plants release an oil into the earth around them which is designed to delay the germination of seeds until wetter conditions can support growth. In the same soil there are bacteria which produce a chemical compound known as geosmin. When a raindrop hits the dry earth, it bounces back producing tiny droplets with an aerosol effect that releases the combination of oil and geosmin. Similar to using a fragrance spray. The resulting odour is petrichor, so powerful that man and beast can sense it at a distance. In fact, its sensitivity by humans is attributed to our ancestral survival, enabling us to find water sources purely by following the scent. It is this aroma, which as I mentioned at the start of this blog, makes me smile as a hunter. It guarantees a damp, silent woodland floor without being over-soaked and treacherously muddy. You won’t smell petrichor after torrential rainfall; the deluge drowns the aerosol effect.

The main quarry in this small wood is the grey squirrel but I’m always alert for other pests. One interesting find today was a hen pheasants wing. The birds killer had left its scat on top of the feathers, much as a fox often does. The predator this time was a stoat.

I set up in a corner of the wood where the squirrels travel from drey to the landowners bird tables. Happy with a hat trick, I went walkabout with the camera, enjoying the wren and robin song but the spot of the morning was a hobby hawking insects over the water meadow – no doubt enjoying the insect supply which the new herd has brought through their dung.

© Ian Barnett, Wildscribbler, May 2022

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