A pygmy problem

Outdoor Living

SMALL BUT PERFECTLY FORMED Our tiny pygmy shrew faces an uphill battle since its loutish larger cousin’s arrival to these shores.

Country Sights and Sounds
John Shelley

I had shrews again. Having enjoyed the company of these funny little creatures before, I knew the signs.
First, there was the sound of those tiny feet scampering over the wooden floor. They patter for a yard then pause, then skitter off in another direction, as if the owner of them had a sense of urgency yet didn’t really know where he was.
Down went the mousetrap, loaded with a nice dab of peanut butter. In the morning it was licked perfectly clean, but was otherwise undisturbed. When the same thing happened again the following night I knew a couple of shrewd modifications would have to be made so the trap could be set on a hair trigger.
That did the job alright. Snap! went those serrated jaws; there was a brief moment of unpleasant scrabbling of tiny nails and the intruder was dead. Yes, I know there are humane traps, which enable a captured animal to be released unharmed. But one thing we are not short of is rodents.
Perhaps I should apologise to the shrew family, for these animals are not rodents at all, no matter how much they look like mice. They are insectivores, and get by on a diet of beetles and wood lice.
Anyway, the body of the shrew was thrown out, but before it went I couldn’t help but notice how large it was – for a shrew, that is. It looked to be pregnant as well. The following night I caught its even larger companion and am once more freed of an impending plague of unwanted house guests, albeit temporarily.
I thought no more of the matter until I found another similar animal, this time while walking with an American visitor. There was the little body, lying on its back on the woodland path. Again, I could see right away it was much larger than the native pygmy shrew, and a closer examination showed me a couple of key identifying features.
First there was the tail, which was sparsely covered with stout, white hairs. And then there were those gleaming white teeth. The pygmy shrew has iron deposits on the end of its incisors, which gives them a red or brown tinge and helps to prevent them being worn down.
This was no native then, but was a greater white-toothed shrew, one of a species rapidly colonising much of the island of Ireland after being first recorded in 2008. (There is a lesser white-toothed shrew as well, that hasn’t yet been found here.)
An adult female greater white tooth will continue to produce offspring as long as the weather and the food supply allow. She will certainly breed from April through October, and is capable of giving birth to a litter of babies every four weeks or so. Each litter might contain as many as ten shrewlets (four is common), each of which reach sexual maturity within a few weeks of birth. It’s just a wonder we aren’t overrun.
Why are they a problem? Perhaps they aren’t, unless you care for the native and very tiny pygmy shrew.
The difference in size might be illustrated by comparing our own height and weight with that of another. The greater white-toothed beast is commonly three times the size of the diminutive and rather comical pygmy. So imagine yourself at the bar next to a much taller, far broader and three times heavier individual, one with an insatiable appetite for beer and peanuts. Who is going to get their pint first?
You’d soon be looking for another bar. But when you find one, why, there’s another big fellow taking up all the space and helping himself to your scoops. And there’s nothing you can do about it.
So the poor pygmy is being displaced throughout its territory. When the white-toothed lad first turned up in Ireland it was thought the two species might live side by side. We now know that is unlikely to happen.
When did I last see a pygmy shrew? I really don’t know. I shall be on the lookout now.
One ameliorating feature of the new arrival is that it has the ability to turn a healthy insect population into a nice, bite-sized packet of protein for larger predators. The stoat, the pine marten, the badger and the fox will all be happy to make his acquaintance, as will any number of birds.

Michael Kingdon formerly wrote these columns under the pseudonym John Shelley. A naturalist and keen fisherman, he lives close to the shores of Lough Carra.