While referring to something completely different, Donald Rumsfeld memorably said
"There are known knowns. These are things we know that we know. There are known unknowns. That is to say, there are things that we know we don't know. But there are also unknown unknowns. These are things we don't know we don't know."
This intriguing statement came to mind while I was pondering the less evident wildlife around us in Les Albères. The known knowns are obvious and are species that can be clearly identified such as some insects, red squirrels, rabbits, birds, hare; with luck some maybe photographed. Our website tends largely to deal with these.
At the other end of the scale one wonders, too, about the unknown unknowns as no reference book is likely to be all-encompassing. Sometimes these would be species that simply got lost on a migratory journey, got swept in by intemperate weather or just extended its usual range. It would be wonderful and exciting positively to identify one of these - a serendipitous moment! Hope springs eternal.
Then, and this is the main thrust of this blog, there are the species that we just don't see at all, but the books tell us are, or ought to be, there - known unknowns or perhaps in this case "known unseens". Our local reference book L'Albera describes many species like this which one never encounters; but that does not mean they are not there, happily living out their lives away from our gaze. The obvious candidates will be crepuscular, nocturnal or simply shy animals such as pine marten, otter, badger and deer.
Finding evidence of the known unseens is always at the back of my mind as I roam happily through our lovely area. I usually walk with my eyes to the ground - thus missing the birds, but hey, one can't have everything. And it is on the ground that one finds tracks and traces of these unseens.

I have seen tracks of what I suspect to be Roe Deer (Capreolus capreolus).
(As an side, I have actually seen what I think was a red deer (Cervus elaphus) one day quite close to Montesquieu. It was in a wooded area and came out of cover just ahead of me. Before I could grab the camera it had darted back. It was too big for a roe deer, being well over a metre at the shoulder.)

Sadly, I have seen a dead one near the lake at St. Génis, and Lesley saw what looked like one that had been run over near the bridge taking the D914 across the river Tech near Palau-del-Vidre.