Apologies for the lack of information or a picture of the birds (two) seen very briefly.
Location open shrub land in SE Nigeria (10km from the atlantic coast), mid morning
Two birds lifted off from the ground & flew/glided away from me
Wingspan approx 30cm
Most noticable distiguishing marks were what appeared to be feathers (Scallope shaped) trailing from the rear or wings. The drawing may not be that accurate in that respect as they show rear training feathers coming from the body; though my initial impression that they came from the wings. The sighting lasted a couple of seconds.
Colour dull/drab as I didn't really notice any bright colours