Oh, thanks for pointing that out, Hix.
It looked very similar to mourning doves that were pointed out to me in Tarangire so I didn't check these ones properly. Should've done really.
Red-eyed, Mourning and Ringneck Doves all look very similar but the difference is in the eyes so you need to get a good look at them. All three are fairly common in East Africa.
Ringneck Doves have black eyes.
Red-eyes Doves have dark red eyes, which can look black in poor light, and pinkish skin around the eyes - in the photo above when you enlarge it you can see the red tinting to the eyes.
African Mourning Doves have a white eye and dark pupil, with orangey-red skin around the eye.