Tuesday, 25 August 2009

Do different colonies have different habits?

Nice clear shot of a water vole's tail.
Anecdotal observation: when I go round the area to check on the various colonies, I find they leave different sets of field signs. The ones at the bridge near Homebase are still making feeding stations, whereas as White Lion Meadow it's just grazing I'm seeing. Down in the country park there are lawns and burrows and slipways but no obvious latrines; in the field near my house it's latrines all the way. In addition, there are some colonies who demolish any watercress down to the stalks, while others leave it untouched.
I know in general latrines mean breeding females, so when I fail to find any latrines it may be a lone male's territory I'm looking at (or, more likely, that I'm just not spotting them - but then why do some water voles leave droppings in very obvious places, while others seem to hide them away?).
Maybe the feeding stations are to do with the kind of plants available, though I seem to find more in the spring than later on in the year, so I have a feeling it might be seasonal too.
And perhaps the percentage of watercress eaten depends on what else is available; it's possibly way down the list of what they like to eat, so if something better's on the menu they'll go for that first.
But it does seem odd that certain field signs characterize certain colonies to such a degree.


Richard said...

Interesting questions, which I'm afraid I can't answer.
But as you speculate, maybe it has something to do with the male / female ration, the age of the colony and the age of the voles?
Just some thoughts.

Kate said...

It could well do. Obviously with things like burrows, you only get them in certain waterways because of the terrain. And I've heard that where streams are very steep-sided with no shelving, surveyors sometimes have to put down pieces of polystyrene for the voles to make latrines on.

I suspect the feeding station business is maybe linked to what vegetation's available - but that said, some areas have feeding stations early on in the year, and then just grazing later on the same plants.