On Wednesday, January 14, 2015 at 9:39:38 AM UTC, Martin wrote:
A farmer in Friesland has 45 hectare of meadows full of holes. The holes are
made by mice which tunnel to access gras roots, which they eat. His fields are
like a desert. He says he is going to have to plough them up and reseed them.
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Martin in Zuid Holland

Mice! More likely Moles or Voles.