Dena capensis is incorrect. The bird is correctly known as "Oena capensis".
Stamps inscribed SAHARA OCC. Have been denounced by the Morrocco postal administration as illegal since the year 2002 when they first found out about them being sold on the philatelic market. The circulars are No.414 in 2002, No.69 in 2004 and No.71 in 2008. All illegal stamps inscribed SAHARA OCC. were produced and distributed to the philatelic market by illegal stamp producing entities located in the UK and Eastern Europe. There have never been any functioning post offices located in the region under the control of the Sahrawi Arab Democratic Republic at the time the illegal stamps were produced.
