I admire your plumage!
They have the perfect camouflage. Their bright colours look stark against this tree while leaving the nest, but when they are feeding in noisy groups it is quite hard to distinguish them. The bright orange mimics the sunlight filtering through the leaves, the blue melts into the shadows of the underside of the leaves, and the green blends with the overall foliage.
Maybe they were thinking out loud. Or perhaps discussing what to have for dinner. Tawny frogmouth noises are just right to listen to.