12 December 2009

Giants and Pygmies

Not far from the lane is an area of the wood which a Georgian forester must have thought suitable for Norway spruce. He may have dreamed of leaving them to his grandson’s son to sell as masts for sailing ships, or simply as the raw material of the new literacy. He planted well; his trees grew strong and tall, but as they grew the markets changed. Steam replaced sail; cheaper woodpulp came from Scandinavia. The trees matured and were not harvested, and yet lived on.

Now many of these giants are reaching their term. Some are dead already, the bark peeling, the exposed heartwood bleaching grey, the roots and base sprouting telltale brackets of white fungus. A few have already crashed, and where the trunks and branches block the rides they are quickly cleared by men with chainsaws. The timber is good for little by that stage; it is probably burned.

In a quiet part of the spruce grove, a few yards from the nearest path, one of the trees, similar to its neighbours in every outward respect, has been singled out by a tawny owl. To the same broken stub of branch the bird comes time after time to rest and in peace and silence digest its meals. This December morning, in the half light of dawn, it is here again. Its great head turns; it blinks, makes a slight retching motion, and brings up a wet grey mass, a pellet of indigestible fur, bone, earthworm bristles, feathers, claws. The pellet tumbles eleven feet to the ground and comes to rest among a score of others of varying age.

Preserved in these capsules is the history of the owl’s diet. If you know how to read them, the fragments of bone reveal much about the small mammals of the wood. Of course, the owl may have its personal likes and dislikes; it is not an impartial sampler. To get information of scientific value requires the dissection of many pellets from many owls over a great period of time, as was indeed done by one zoologist in a clever and original study. Taking these few home in a plastic bag, though, might tell us something, perhaps, that we do not already know.

With a lens and textbook the tiny bits of bone, cleaned now and dry, can be roughly sorted. Skulls in various stages of destruction, halves of lower jaws with or without teeth, assorted molars and incisors. Vole this side, shrew that. A wood mouse skull, or what’s left of it. This lumpy-looking thing is a mole’s humerus. A flat, fluted wishbone: the lower mandible of some dunnock-sized bird.

Among the shrew jaws there are two, both right-hand halves, which are obviously smaller than the rest. And here, in the as yet unsorted pile, is an upper skull barely half an inch in length. It once belonged to a pygmy shrew, the smallest of all our mammals. Handled like this, turned in stainless steel tweezers under a desk lamp, it seems impossible that a skull so small could once have held a mammal’s brain or housed even such a quick, ferocious and hyperactive soul. Shrews do not live for long. Their existence is all aggression, greed, sex, a headlong madness to cram each minute full.

A year or two ago you found one drowned in the greyish fluid that had gathered in the bottom of a discarded preserving jar. The jar had been inside a sack of rubbish dumped in the ditch by a passing motorist. A fox, smelling chicken bones, perhaps, had torn the sack open and out had spilled the jar, coming to rest among the nettles. There it had lain, waiting for the shrew to find it and stumble inside.

That death was easy enough to understand; but what caused the end, last July, of the shrew you found dead in the middle of the path? The body was cool, but still limp. There was no sign of injury or any other cause of death. The nervous system, already running on maximum, may simply have conked out; or there could have been a failure in some vital valve of the perennially over-revved and overloaded heart. A pygmy shrew is miniaturization taken to extremes.

At that size nature is pushing the very limits of design, just as, at the other end of the scale, it is pushing the limits when the huge crown of a long dead spruce, yielding at last in the lifelong fight with gravity, splits off and falls with a thunder that makes the whole forest quake.

(Introduction to these pieces; see all)

No comments: