Javan Myna Anting Asian weaver ant

This Javan Myna was photographed at my backyard. When I look at a camera LCD, these two insects are hanging at the tail feather of a Myna.  Close-up of the insect identifed as "kerengga" Asian weaver ant (Oecophylla smaragdina)

Anting is a maintenance behavior during which birds rub insects, usually ants, on their feathers and skin. The bird may pick up the insects in its bill and rub them on the body (active anting), or the bird may lie in an area of high density of the insects and perform dust bathing-like movements (passive anting). The insects secrete liquids containing chemicals such as formic acid, which can act as an insecticide, miticide, fungicide, or bactericide. Alternatively, anting could make the insects edible by removing the distasteful acid, or possibly supplement the bird's own preen oil. Instead of ants, birds can also use millipedes. (Wikipedia)

Kerengga di ekor Tiong

Javan Mynas have been reported to use anting as a means of feather maintenance, where they rub insects, usually ants, directly onto their feathers and skin. This behaviour forces the insects to secrete formic acid which acts as an insecticide and bactericide. (Bird of the World)