Scraping from right to left (deposit on left). (i) Fresh pellets and (ii) disturbed soil distinguishable from surroundings suggest very recent deposit. Some pellets as deep as 30 mm in this case, a few left exposed though with adhering sand layer. In my experience, the deposit can (i) be left exposed, (ii) be totally missed by the scraping, (iii) get hardly more than a fine layer of dust, or (iv) be totally buried with no pellets visible.