I saw a Wood Mouse the other day while on the nature trail. Nothing strange about that, you may say. Maybe not, but I thought it was unusual as the rodent was out in broad daylight in the middle of the day.
When I say I saw it, what I mean is that it saw me first and what I saw out the corner of my eye was the sudden movement as with explosive acceleration it darted from a standing start to the safety of cover in the undergrowth. That said, I did get enough of a fleeting glimpse to know it was a Wood Mouse.
We have two species of mouse in Ireland: the Wood Mouse and the House Mouse. The names suggest that the former is found in woods and the latter is found in houses, but it is not as simple as the names suggest.
The Wood Mouse is very widely distributed and is a generalist, found in all habitats including houses. It has orange-brown fur on its sides and back and a white belly. Its eyes are large and jet black. Its ears are also large and are almost hairless. Its nose is pointed, and it has long whiskers.
The big dark eyes, the large ears and the golden fur give it an appealing appearance. The fact that is clean and odourless adds to its appeal as an attractive little creature.
The distribution of the House Mouse is poorly understood but it is known that it is closely associated with people and their buildings. It is found in cities and towns and in rural buildings. Its strong association with people is evidenced by the fact that House Mouse populations on offshore islands die out very quickly when people abandon their island homes and relocate to the mainland.
The fur of the House Mouse varies in colour, but it is generally grey. Its eyes and ears are small, and its head is narrow giving its face a 'mean' expression. It uses its urine to scent mark its surroundings, so it is smelly. Consequently, houses with an infestation of mice are non-smelly if the invader is the Wood Mouse but have a distinctive 'mousey' smell if the culprit is the House Mouse.
The House Mouse is an introduction that arrived in Ireland with immigrating people. Genetic studies show that our stock has closest genetic affinities with populations in Scandinavia, Scotland and England.