The Mangrove Whistler is a small, drab bird with greyish-brown upperparts, white underparts, and a distinct black bill and eyes. Fairly common resident in Malaysia’s coastal mangrove forests and adjacent areas, and also on coastal islands. It can be found on all “layers” of trees, from fairly low to the higher canopy, although it rarely stays out in the open. It is a shy bird but can be located by its sharp, musical calls – hence its namesake – whistler.

It is inquisitive and easily drawn out by mimicking its whistle, but sometimes can be mistaken for a (female) flycatcher.

Common over all districts of Seberang Perai and also on the Island.

https://datazone.birdlife.org/species/factsheet/mangrove-whistler-pachycephala-cinerea