We now own the field next to our house.  It has stood empty of grazing animals for several years and the grass is long and tussocky.  What concerns me is the number of holes and burrows that have appeared all over the field.  The holes are about 50-70 cm in diameter.  I have not seen anything live but have seen voles and field mice in the garden under the bird feeders.  We do have holes and tunnels disappearing under concrete paths around our house too.  I am concerned about rats.  I know they will live amongst rubbish, compost, manure heaps etc - but does anyone know if they will actually burrow and tunnel in grassland?  We have regular visits from the fox and a local cat.

No idea, I'm afraid. Why not ask your local conservation society as well as environmental health to have a quick look for you. I see holes when I am walking the dogs, but have seen bees coming out of them, so they must be an awful lot smaller ;-) My cat brings me back lots of different furries, but never a rat. When my neighbour moved his shed there were a few rats seen moving around for a while. For some reason I got the blame of them being there

I was looking to get more info before calling in environmental health.  No way will I have poison put down now anyway.  Perhaps a terrier? :-) Big article in our local paper about how terriers are being used to rat catch instead of traps and poison.

Holes that big must surely be fox or badger :)

Sound too big for rats to me as well

Do you mean 50-70 cm or mm?

50-70 cm sounds more like the size hole that a badger would make, but 50-70mm could be a rat sized furry (rat, stoat, weasle).

ETA voles & fieldmice are part of the stoat/weasels food source, but rats are very attracted to bird food (and rabbit food :( dirty little rats managed to get into my rabbits run, I wondered why he was getting through so much food & then 1 day IN BROAD DAYLIGHT, saw a rat scampering around his run eating his food - the rabbit never batted an eyelid)

Could it be rabbits? they make decent sized holes, and are prolific burrowers. They have totally trashed our local cemetary, digging under graves, and causing headstones to fall over etc. Its got so bad that they now have allowed men with dogs and ferrets to go to clear the place of them. ( They also eat all the floral tributes!)

Drat that I mean mm silly me!  Too busy thinking of other things when I was writing.  No rabbits seen round here for years. 

We had a weasel under the roots of the tree in the garden about a year ago.  Have moles around too - at least one of the holes in our lawn is a collapsed mole tunnel.  Haven't seen a mole hill for a while though.

Set some humane live catch traps.. then you can see what you have.

Though.. do so on the understanding that if it is rats you will have to kill them, not release them. (Not legal to release vermin).

we have them in our field they are field mice holes, our field isnt used for anything either
please dont put poison down as the woman across the road did this and killed a cat after it ate a mouse that had been poisoned
they are really cute our cat brings them in all the time!

field mice I can live with - such pretty creatures. I would not put any poison down now we have the dog.  I can remember the panic I had when the mice in the attic started to take the poison that I had forgotten about.   Cavity wall filling seems to have stopped the patter of tiny feet.  Although I am non to happy with that dratted cat that sits out there and taunts my dog!!!!  (only joking)