This weird behaviour looks like a kind of display. I saw two, probably male birds doing this for a few minutes, when there was another bird, probably a female, around close by.
Ornate Fruit-Dove, is a typical nomadic dove foraging in large flocks. It is a fig specialist, which is attracted by large amounts of ripe figs. In the vicinity of Kwau, there were several fig trees, which seemed to attract large groups of these pigeons. On one morning we saw two very large groups, of which one of up to 150 birds! The birds breeds usually in pristine mossy forest, but outside the breeding season, they form flocks who can travel down to the lowlands in search for fig trees. I spent one morning and an evening at a hide on a steep slope, which gave view into the canopy of a fig tree. This resulted in great views and pictures of two species of fruit-dove and double-eyed fig-parrot.