Brownish-flanked Bush-Warbler

Cettia fortipes robustipes

Endemic subspecies

The Brownish-flanked Bush-Warbler is a small (12 cm) bird, uniformly brownish above with a whitish supercilium, and light yellowish-brown below, paler on the centre of the throat and belly.  The iris is dark brown, the bill is brownish-gray with a pinkish base to the lower mandible, and the legs are pinkish-brown.  The  Taiwan subspecies has a longer bill and a weaker supercilium than adjacent mainland forms.  Sexes are alike.

The Brownish-flanked Bush-Warbler frequents dense undergrowth, bamboo clumps and grassy edges of clearings in forests, thickets on hillsides, and bush-covered ravines.  It is easily heard, but its skulking habits make it difficult to find or to flush into view.  Its song consists of a loud whistling “weeeeee” followed by an explosive “chiwiyou” or “tyit tyu-tyu”.  Its call is a harsh “chuk”, sometimes repeated persistently.  It is an active bird, and usually solitary.  It feeds on small invertebrates such as insects, including their larvae and eggs.  The nest is a ball or deep cup of dry grasses, leaves, moss, other plant fibres and feathers, placed in a low bush or other thick vegetation, usually within 1 m. of the ground.

In Taiwan the Brownish-flanked Bush-Warbler is common resident year-round at moderate to high elevations, descending to lower levels in the winter.

References:  A Field Guide to the Birds of China (Mackinnon and Phillipps);  Handbook of Birds of the World Vol. 11; N. J. Collar, “Endemic subspecies of Taiwan birds—first impressions”, in Birding ASIA, Number 2, December 2004