Wildlife Enhancement on Prince Edward Island
Mice and voles

Most Island mammals are small. While there is no exact definition of ‘small mammal' (some authors suggest anything under five kg or 11 lb) it seems unfair to lump a 1,500 g (3.3 lb) hare in the same category as a 10 g (.35 oz) shrew. I prefer a more subjective approach - a mammal that fits neatly into the palm of my hand is a small mammal. That will do nicely for mice, voles, shrews, bats and even squirrels - all more or less well known Islanders.

It is worth thinking for a moment about the ecological advantages or disadvantages of being a small mammal. If you are small enough, you can make a comfortable living eating uncommon or sparse foodstuffs. A few small seeds here, a bite of fungus there, while one acorn can be a banquet. Lots of places to hide, if you are tiny. Many micro-climates within a small area, so several different species can coexist. There are draw-backs to being small, but they are outweighed by the advantages. So the Island can support six mouse species, five species of shrews, three of squirrels: rather more than half of our mammalian array right there!

Let's begin by taking a closer look at the six mouse species that we live with. The differences between mice and voles are not very significant. Mice have large eyes, large ears, long tails (at least as long as their bodies). Voles have smaller eyes, smaller ears concealed in their fur and shorter tails. However, if you want to call a field vole a field mouse you will not offend anyone but a passing taxonomist.

	
	The local list includes:


	Field vole/mouse 
	Microtus pennsylvanicus
	Grey to black with a short tail.
	Poor climber.

	Red-backed vole	
	Clethrionomys gapperi
	Similar, smaller, reddish colour.
	Woods-dwelling.

	Deer mouse
	Peromyscus maniculatus
	Grey above, white beneath.
	Our cutest mouse.  Woods-dwelling.

	Meadow jumping mouse
	Zapus hudsonicus
	Long hind legs and tail.
	Jumps like a kangaroo.

	Woodland jumping mouse 
	Napeozapus insignis 
	Similar, but woods-dwelling.
	Our best jumper, able to leap
	up to 2.4 m (8')

	House mouse	
	Mus musculus
	All too familiar.  Exotic.  Gray-brown
	above and nearly as dark below..

these mice vary from common to uncommon, depending on year and location on the Island. Mice populations are notoriously unstable; this is particularly evident in the field mouse. One year they may be so common that the ground seems to be plowed with their burrows, while the next they may be hard to find. Their lives may be short yet the species survive quite well. Let's look at the individual species.

Found anywhere in open grass-land, along hedgerows, even in suburban yards, this fat, friendly mouse is active throughout the year. In winters with good snow cover (giving predator protection) the population builds rapidly, and in spring the colony activity pattern is readily traced as the snow disappears. This mouse is not always beloved; he enjoys stripping the bark from apple, hawthorn and other trees or shrubs. While some still try to control this behaviour with poisons or repellents (really poisons as well) the only real protection is a mouse-proof barrier around the tree. In early years on the Island plagues of field mice seriously threatened human food supplies; now he is just a bit of a nuisance. On the positive side, this mouse is staple food for fox, coyote, owls, several hawks, and is thus important to our environment.

Smaller and usually less common than the field vole, this nice guy is readily identified by his reddish back and sides. This rodent is strictly a woodland-dweller, at least locally. I often see them along old stone dikes running through abandoned farmland which has reverted to forest. Also important to avian predators, this animal will thrive as long as there is reasonable cover, such as coarse debris, in the woods.

Most people encounter this adorable mouse in woodland cabins, although sometimes they will move into other buildings near the woods. They feed on seeds, nuts, berries, insects and subterranean fungi. This grey-above, white-beneath mouse with his big ears and eyes is a most attractive Island rodent. A word of caution: deer mice may carry the dangerous hanta virus, which can infect humans with serious results. While relatively few Canadians have died from this virus, it should be avoided as the mortality rate is quite high. The virus may be found in droppings, so be careful around the cabin!

I am amazed at how many people have never seen these reasonably common Islanders, although I have to admit that I seldom encounter the woodland species unless I'm trapping them. These guys are like miniature kangaroos; they rocket out from under your feet with several long jumps. I suspect they are a trial to predators, which include weasels, mink, skunks and owls. They are unlike their other mouse relatives in being true hibernators, and thus may live a somewhat longer life.

Leaving aside the house mouse, who is perhaps too familiar to everyone, we still have a good array of woodland and meadow mice. In many cases their role in our environment is still a mystery. They spread seeds and fungi, support predators, usually live short and busy lives. Aside from such generalities we know little about their ecology and exactly how they influence their surroundings. For my part, I just enjoy meeting them.

The Macphail Woods Ecological Forestry Project, a member of the Island Sustainable Forest Partnership Cooperative with assistance from Natural Resources Canada, the Canadian Forest Service and the Model Forest Program have put together this series of information sheets concerning Wildlife Enhancement on Prince Edward Island. Thanks to Beth Hoar from GreenThumb Photography. Web development and maintenance by Chris Martin.