Sunday, 26 April 2009

Fordhall Mystery

Fordhall feeding

Prees Branch Canal feeding (the pics below, too)

White Lion Meadow water vole from last night
We had a report of a water vole sighting at Fordhall Farm in Market Drayton, so Rosie and I went to have a look. There was certainly otter presence - we found prints and spraint, both old and fresh - but we couldn't draw any firm conclusions regarding voles.
The problem, once again, is these pesky field voles. Field voles are really common and you'll find their tiny light green droppings, little trackways and £2 coin-sized burrows in fields and banks all over the place. But they also like water, and often choose to live by streams or ponds. I've seen one swimming in the brook at White Lion Meadow. And the issue for water vole-surveyors is that field voles leave feeding stations that are very similar to water voles: they chop up lengths of vegetation using the same slanted cut, and leave it in piles. Unless there are droppings right next door, it can be impossible to tell the two types of feeding station apart.
Generally field voles cut daintier pieces, and eat thin blades of grass (and also will strip the outer layer off juncus reeds so the white pith shows, which water voles don't seem to do). Generally water voles choose chunkier plants to turn into feeding stations - thick, broad-bladed reeds, for instance. However, there's a medium length where it's hard to say which mammal's been doing the chopping, and that's what we have in the top photo taken at Fordhall Farm last week.
The only difference between the top photo and the other three, taken at the Prees Branch Canal reserve and definitely water vole, is scale. The Fordhall pieces are grass, while the others are chunky reed. I should have included a coin, to show the difference.


Richard said...

An interesting post.
Field voles could explain some of the eaten reeds I've seen today in dried up ditch.

Kate said...

Field voles very often poo on their feeding stations, which is helpful for IDing, so watch out for that. The other characteristic field vole thing is the stripping of the outer layer of juncus lengths. Beyond that, it's often down to guesswork!