Stoat's dainty steps a vital part of the great dance of life

Ireland’s biodiversity is not half bad, if you count in our migrant birds, our species-rich shore and sea, the newly plumbed genetic inheritance of our native wildlife. Even our diversity of snails, creatures so derided by a certain strain of politicians, can have important agricultural value. In a public lecture now offered on YouTube by UCC, Sleeman explains how the liver fluke, damaging parasite of sheep and cattle, needs one particular snail to host part of its life cycle. With so many snail species available, it meets a lot of failure and so its harmful impact is diluted.

A classic ecological lesson is the story of Lyme disease, a tick-borne illness potentially debilitating in people and now making some headway in Ireland. It is named for a town in Connecticut, in the US, where suburbs expanded rapidly into woodland. The woods originally had 15 kinds of mammal the tick could latch on to but few of which would give them the disease in their blood.

After the woods were invaded by houses and people, the mammals were reduced to one, a mouse that could pass on Lyme disease. Now free of predators, the mice were concentrated in the remaining undergrowth, so were more and more infected ticks. This pattern and its consequences helped to spread the pathogen to people across the north-east of the US – and now, it seems, beyond.

You can watch Sleeman’s lecture on YouTube at iti.ms/PTE8F0

Eye on NatureYour observations and questions

I found two dead shrews in my garden, one in the water butt and the other, smaller one on the ground. The larger one had a very large tooth, like a fang; the smaller one had no visible tooth. How did one climb so high as to fall in the water?

David O’Connor Castletroy, Co Limerick

The larger shrew sounds like the greater white-toothed shrew, new to Ireland but found in recent years in Limerick and Tipperary. Shrews can climb and starve if without food for more than a few hours.

The worm-like lad in the photograph I’m sending you has appeared in our house, climbing up walls and curtains. Black and about an inch long, it curls into a ball when touched.

Brendan Foley Enniskerry, Co Wicklow

It is a millipede, Tachypodoiulus niger.

Recently I have seen two grey crows working together to chase a terrified squirrel. At one point a crow had the tail in its beak. Were the crows having fun or hoping the squirrel would stay away in the spring, egg-laying season?

Patrick Davey Shankill, Dublin 18

Probably both.

There is a fox family and wildcat mayhem nightly on the lane, with the odd badger thrown in.

Robin Reilly Washington Lane, Dublin 14