Exactly a week ago, to the hour, I was having lunch outside at Le Caveau in Grand Pre in Nova Scotia, celebrating our golden wedding anniversary, when my wife spotted a bird overhead. I am not spoiling the coincidence by labelling it - I had never seen one before and identified it later.
JackHave sent a PM. The file size from the 5DIV is, I would guess, be even higher than for the 5DS R as there are effectively 60 mps because of the split pixels. And, I don't think you would want to do bird photography in an iso range greater than that of the 5DS (>12,800).