Unfortunately, these pigeons, which were feeding at a fruiting tree near Borba, south of Manaus on the rio Madeira, were not vocalizing which makes their identification somewhat problematic. They are either Ruddy Pigeon Columba subvinacea or Plumbeous Pigeon C. plumbeus.
My original identification was Ruddy Pigeon based on the HBW which says: "iris ranges from pink to purplish red to brownish, with pale inner ring; orbital skin dull red", while for Plumbeous Pigeon it says: "iris red; orbital skin purplish red". However, Hilty, in Birds of Venezuela, says of Ruddy Pigeon: "eyes red... note eye color (yellow in Plumbeous Pigeon)" which is all a bit confusing.
Can anybody help with the id?