The Red Notebook

While clearing away yet more molehills from my front lawn the other day, I made an observation which is almost certainly pure coincidence, but which I record here for posterity, in case it turns out to be remarkably profound:

The holes in the middle of molehills almost invariably appear right underneath or immediately adjacent to dandelion plants. I wonder if moles deliberately choose to make their tunnel entrances next to dandelions. Perhaps dandelion roots are a good indication of where it is sensible/safe to surface.

That is all.

A load of soil this afternoon

*Sigh* A mole has literally set up digs in our front lawn. We don’t usually get troubled by them in the summertime. The first hill appeared earlier this week and, five days later, we had a whole range of them. Bioturbation, it’s called.

I just spent an hour removing the molehills. There was enough soil in them to fill a rather large wheelbarrow. Not bad going for five days’ work. Moles are industrious little gits.

I dropped mothballs down the holes I uncovered. That usually sorts out the problem. Moles don’t seem to like the smell of camphor.

Postscript: Ga! Half an hour later, and there are two new molehills in the garden. I actually saw the mole’s nose pushing out the soil. Of course, you realise this means war.

Charles Darwin had his Sandwalk; I have my Moor Walk: a 3.4-mile circular walk from my house, up the hill, across the golf course, on to the moor, up to Trig Point S4643, through the heather, back down off the moor, down the farm tracks, past (!) the local pub, along the lane, down the bridleway, and back to my house.

I’ve lost track of how many times I’ve been on my walk since August 2001 when we moved into what will almost certainly be, as Down House was for Charles and Emma Darwin, our permanent place of residence for the rest of our lives. The Moor Walk is my thinking walk, which takes up a couple of my hours most Saturdays.

The thing I like most about the Moor Walk is that it is the same walk. Apart from the occasional diversion, I walk almost exactly the same route every time, always in the same anti-clockwise direction, always pausing at exactly the same spots. I even have nicknames for some of the stopping places en route: the Pond Skater Puddle, the Rabbit Shed (deep in the heart of Rabbit Country), the Lucky Field (where I nearly always spot something interesting). Familiarity doesn’t breed contempt; it makes the Moor Walk very personal, and very special. The Moor Walk is my walk.

The South Pennine moorlands aren’t exactly rich in wildlife: the acid soil and the blanket cover of bog grass and heather see to that. But the wonderful thing about going on the same walk over and over again is that you always appreciate when you see something new, and you know what to expect to see at certain times of the year. Yesterday on my walk, for example, in addition to the usual red grouse, meadow pipits, lapwings, curlews, rabbits and pheasants, I saw my first wheatears and ladybird of the summer, and heard my first skylark. The swallows are late this year: I have seen them in the lowlands, but not above the moors. Not yet.

Nature dead in tooth and paw yesterday.

Wheatears, one of my favourite birds, are, like stonechats, only an occasional treat on the Moor Walk, which makes seeing them particularly special. But the most unusual thing I saw on my walk yesterday was on the muddy bridleway less than 100 yards from my house: a dead mole.

Doubtless, had Darwin chanced upon a dead mole during his Sandwalk perambulations, he would have popped its corpse into his pocket, taken it back to his study, boiled it, stripped away the meat and flesh, and closely examined its skeleton with the aim of writing a short paper on how Talpa europaea is wonderfully adapted for an underground life eating his beloved earthworms.

I, on the other hand, left the mole for the crows. There is a limit to how far one should attempt to emulate one’s heroes.

There are 13 molehills on my back lawn at the moment. There are whole mountain ranges of them in the adjoining fields, but my lawn usually escapes the worst of the seasonal attacks due to the large amounts of rubble that went into its construction. Moles don’t like rubble it would seem. But one of the blighters has now found a soft patch at the base of my sycamore and is having the time of his life. Actually, come to think of it, all the molehills I have ever had in my garden have been near the base of trees—I wonder if that’s significant.

Anyway, it turns out that moles aren’t just garden menaces, they are agents of bioturbation—a cool word meaning that, like earthworms, they rework the soil, thereby moving and improving it.

I learnt this new word yesterday from a story which came up in one of my automated Charles Darwin news feeds. The story mentioned a paper published by researchers at the Netherlands Institute of Ecology, entitled Bioturbation: a fresh look at Darwin’s last idea (4.7 Mb PDF), which clearly I had to read.

Darwin’s wormstone in his own back garden in Kent is one of the world’s oldest ongoing scientific experiments, measuring how bioturbation gradually causes objects on the surface to be buried. [Photo (cc): Richard Carter]

It’s a fascinating read, explaining how Charles Darwin was the first person to realise the importance of bioturbation (although the word was yet to be coined), and how his final book on earthworm bioturbation continues to inspire studies in the fields of ecology, pedology, hydrology, geomorphology, and archaeology. Not bad for something that Darwin himself described, with typical modesty, as a ‘curious little book of small importance’.

The paper goes on to explain how the evolution of hard body parts in the pre-Cambrian is now thought to have given organisms the opportunity to begin burrowing for the first time, thereby changing ecosystems on a global scale, and probably becoming a major factor behind the Cambrian Explosion.

Darwin appreciated better than anyone how the slow-but-sure actions of tiny creatures such as coral polyps and earthworms can have major repercussions on the geology and ecology of the planet. The suggestion that they could also be major influences in the history of evolution would have delighted him.