2010-11-01 Lower Austria, district Gänserndorf (just outside of the WWF nature reserve March-Auen, 141 m AMSL). To the left you can see the way the beaver comes: from the water, obviously. Oak wood is very tough, and usually (in my experience) beavers prefer the softer wood of Salix
and Populus species. (Also, it is less palatable - see remark of Sciadopitys
below.) See also this shot here.
Beavers were extinct in Austria and almost extinct in Europe some decades ago; since the 1970ies a project to re-install them again proofed to be extremely successful: the tree-felling rodents have become a common occurrence again (and even a nuisance, say some: I've heard reports of them felling trees in gardens right here in Vienna). German name: Europäischer Biber