Saturday, 1 July 2006

Overground, underground

The other morning, while walking in the forest, my attention was drawn to the sound of movement amongst the leaf litter. This happens fairly often in the forest and I usually make a habit of standing still to see if the creature will reveal itself. Most often it turns out to be a blackbird turning leaves in search of food or a squirrel but on this occasion it was two moles. It is unusual to see moles above ground and, as I stood patiently, I was able to watch their antics. One of the moles seemed to be using a temporary surface run and kept emerging from this to chase a second darker individual. There was no direct aggression and it all seemed rather half-hearted. After several minutes they disappeared in different directions and I was left alone.

The presence of moles is usually revealed by the spoilheaps they create as tunnels are excavated. The spade-like forelimbs are used to dig away soil which is then pushed behind the cylindrical body. Once enough has accumulated, the mole turns round and pushes the spoil along the tunnel and up an already excavated shaft to form a molehill. Such molehills are most evident in pasture and when produced on our manicured lawns but the mole is a highly adaptable species able to live in many habitats. In fact, deciduous woodland would have been the original habitat used by this species prior to the expansion in farming. Under certain circumstances, particularly in low-lying areas like the Broads, more permanent hills may be constructed. Often termed ‘fortresses’ these contain several radiating tunnels and a nesting chamber. The temporary surface tunnels, of the type I witnessed in the forest, are formed as individuals explore beyond their normal range. It is usually the males that do this as they set off in search of females. The two sexes are solitary for most of the year, occupying largely exclusive territories. Occupancy of a tunnel system is denoted through the use of scent marks, a useful feature since both sexes are aggressive towards intruders. Pregnant females give birth to 3-4 young in spring and may sometimes have a second litter later in the year. Although born naked and blind, the youngsters are ready to leave the nest within 5-6 weeks.

Watching these moles revealed some of the features that help them make a living underground. I could make out the cylindrical body shape and the powerful forelimbs, but not the tiny eyes nor sensitive snout, ideal for a fossorial way of life. Their overly-animated movements were fidgety, as if they felt insecure above ground, leaving me with a strong memory of what I had seen that morning in the forest.

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