Many of the kingfishers of Southern Thailand have this same bluish patch. The voice of this bird is also quite distinct, a loud, piercing, descending whistle. Once you heard this, you will not likely forget it. There are 46 species of hornbill worldwide. Thailand has 12 species.
Hornbills make their nests in holes in trees.
Dipterocarpus, massive straight-trunked trees, are a popular species for hornbills to build their nests. If you see hornbills, there is some nice jungle somewhere nearby. The female seals herself in a hole using mud and droppings. This helps prevent predation. The male's role is that of a food provider.