I lean toward explanations that involve commercially cultivated crops. I believe, now, that grape seeds would be too large. That each scat was so homogeneously FULL of these seeds tells me that the full meal was from one source. This suggested plenitude, not a mix of "seeds and mice" for example, that might have been casually foraged.
I took a look at a garden variety (literally) juniper bush's seeds, and I can't imaging a critter being able to harvest so many such berries in one sitting (*censored*ting?). There are only two seeds per berry, and the berries are pretty small and distributed around the bush somewhat sparely. Again, this is in our garden, and not looking at wild plants, so I could be wrong here.
