Thailand, Bangkok - species ID based on distinctive nest? (1 Viewer)

The droppings at the entrance and also on the ground below (not pictured) made it clear this is an actively used bird nest. Photo taken in Sri Nakorn Kuen Khan Park near Bangkok. This nest was perhaps 1.3m off the ground above a small canal; its size is roughly equivalent to a basketball.

I waited for a bit and didn't see anything coming or going, but I could hear a soft murmuring which I assume were the nestlings inside.

Thanks for any help!

Bumping this thread up for more attention.

Mud construction reminds me of swallows, but they usually nest right under a sheltering roof (e.g. the underside of a bridge).

I am dude when coming to S Asian nests, but some songbird, judging from faeces? The mud structure is a termite nest. Barbets, woodpeckers and kingfishers drill nesting holes inside these. But the bird currently nesting inside may be not the original hole-maker.