[Strawbale] The top of the bales

[SEAN A]

I have been looking at allot of pictures of straw bale constructions but one 
part thats not clear to me is what you do at the top of a Nebraska type wall 
to encase the bale in masonry or plaster. I have seen some pictures of top 
plates but they all look like they are sitting on straw. How do you close 
the top of the bale? In my climate(Maine) that open straw would be an 
invitation for squirrels and mice. I don't care if straw has no food value 
to vermin it would be warm and that would be a nice invitation in the middle 
of a fall cold snap. I have found plenty of cozy squirrel nests in 
fiberglass insulation.