FieldvoleCam

I have a new neighbour, recently moved in opposite my front door.  It is a field vole and has set up home at the base of an oak tree.  Over the last couple of weeks the holes and adjacent runways have become more noticeable with use and wear.

The field vole (Microtus agrestis) is identified by its greyish-brown colouring and short tail (its other name is short-tailed vole).  Bank voles (Myodes glareolus), which are common in my garden, are slightly smaller, reddish-brown, with a proportionately longer tail.

The field vole builds a system of holes and runways in grass.  This one is in the area that was meadow last year, and will be again this year, perhaps what attracted it.  I first tried my usual low-down camera position but it didn't work for a vole in a runway so I tried putting the camera on a tripod, angled down at about 45°.  Here you can see the vole dashing through the runway and holes as it collects sunflower seeds.

Here is another video recorded at night.  Like most animals and birds I have recorded with this camera, the vole seems unconcerned by the bright lights from the camera.

Here is a closer view of the vole collecting sunflower seeds.

Here it is collecting grass, probably to eat, possibly also for nest material.  Note its short tail.

There are half a dozen or so holes within an area of about half a metre square where the roots of a dead sycamore run across the base of a turkey oak.  The holes must all communicate with the nest inside and presumably allow an escape through a side door if a predator, such as a weasel, comes in through the front door.

Field voles have a lot to worry about.  They are the favoured prey of weasels, barn owls and kestrels and are also hunted by other owls, stoats, foxes, badgers, hen harriers, buzzards, etc.  One morning I opened the front door to see a male kestrel sitting in a birch tree at the edge of the lawn and looking toward the vole's hole 10m away.  Perhaps it had noticed the trail camera and was wondering what the fuss was about.

I read in Wikipedia that a kestrel eats 4-8 voles per day, so roughly 2200 per year, or 4400 per year per pair.  Nestlings each require an average of 3-4 voles per day, there are on average 5 chicks per brood, and fledging takes 32 days, so that is another 600 voles, plus extras for newly fledged birds before they learn to hunt.  In round numbers this means each kestrel pair will get through the equivalent of 5000 voles per year (they do eat other things as well).  Each female field vole produces about 30 offspring per year so you can see it takes an awful lot of voles to feed just one kestrel pair. No wonder there are about 75,000,000 field voles in Great Britain at the end of the summer.

One day the camera detected a burglar.  The first time it sat outside the hole for about half a minute, loitering with intent.  The second time it appeared from inside the hole, ran in and out a couple of times and then ran off.  This is a wood mouse (Apodemus sylvaticus).  I don't know whether it was casing the joint or was hoping to take lodgings.  If you thought a field vole was fast have look at the mouse.

These pictures were recorded with the Wingscapes BirdCam Pro, which has the advantages of adjustable preset focus and white light LEDs for colour video at night.  When I used it on the sparrowhawks last month the pictures were a bit overexposed and the output of the LEDs is not adjustable.  So I have modified it by fitting the lenses from a pair of child's sunglasses from Poundland over the two LEDs.  Whether due to that or not, the nighttime video exposure on the vole and the mouse here looks better.

I hope the vole evades the kestrel and sticks around to enjoy the meadow when it flowers in a few months time.  If it does, and I manage more photos, I'll post them here.