All the smaller pigeons on the image are Orange-bellied Fruit-Doves and the larger bird on the right is a Pink-Spotted Fruit-Dove.
Orange-bellied Fruit-Dove is the most common Pigeon in the lowlands around Nimbokrang. They often move in flocks of varying size, and sometimes they can form very large groups of up to 100 birds. It is found in more open habitat, as well as secondary forest and forest edges. Once one knows their call, they seem to be omnipresent and really common, but as they often forage high up in the canopy, it is sometimes still difficult to see them properly.
Pink-Spotted Fruit-Dove is rarer lowland specialist. It looks very similar to the Ornate Fruit-Dove, which is found at higher altitudes in the mountain ranges. It is a gregarious and nomadic species of forest and forest edge. It shows a foraging preference for large fig trees.
I photographed these birds in the same large emergent forest tree as most of the parrots. I spend there two entire mornings and I saw also Coroneted and Dwarf Fruit-Dove in the same tree on one morning.