Do Beavers Fly?

We lived in Ottawa in 1990 and 1991, and remember the time with great pleasure.  One of the highlights was realising how common beavers were in the area.  Some points:

• We had been there less than a week and went for a walk along a path below Parliament House.  There was a beaver swimming across the River!
• Go forward about 9 months and I took a bunch of visiting European Statisticians to the swamp adjacent to the Brittania Water Treatment Plant.  The guests were very excited to see a beaver: the Norwegian said something like "We have to go a long way from Oslo to see one of them!"
• When Orienteering in the forests it was important to aim for the dam on beaver ponds: that was a nice run across a swamp whereas crossing upstream involved wading a significant depth of water.
• They were also common in the suburbs and the City sent teams out with dynamite in Spring before the steams started flowing to blow up the dams which would otherwise flood houses.  This meant we were quite used to seeing beaver chomp marks.

Hold that last thought and come forward about 24 years.

Walking across the lawn this morning I was surprised to find a moderate sized lump of Acacia dealbata adopting a horizontal 'growth' pattern at point 1.

 Here is a close-up of point 2, confirming the source of the material

 Now looking at this it closely resembles beaver munching.

However, I am reasonably sure beavers neither fly, nor climb thin trees.  The same applies to wombats.  I must therefore conclude that the Yellow-tailed Black-Cockatoos have got fed up with a pure pine cone diet ...

...  and have ripped into the Acacia, searching for grubs.