Now we home school, which means that everything is a learning experience. So I asked my middle daughter if looking at the seeds the doves were eating was educational or icky. She said it was educational, so I cut open the crop of each bird to see what they were eating.
4 birds had empty crops consistent with the 4 birds I shot early on.
Of the others, 2 had these little brown seeds
Pic is one seed pile per bird, after I had cleaned 5 birds.
Another 3 had these large mahogany colored seeds. The smaller darker red seeds are actually two piles.
The last one (not shown) had eaten a mix of the two.
Pic should be clickable.
As a scientist, I find this terribly interesting. As a Physicist, I have no clue what these seeds actually are.