Grey-sided Bush Warbler Cettia brunnifrons has a remarkable song and a striking head pattern, making it one of the easier Cettia to identify. Each of the three ssp. occupies a disjunct range in the Himalayas and on the eastern Tibetan Plateau, with umbratica in southeastern Tibet and western Yunnan north through western Sichuan to southern Gansu. Breeds to 4000 m in scrub and grass both above and below the tree line. Descends in winter to 500 m. Shares chestnut-brown cap with larger chestnut-crowned bush warbler, but head of the grey-sided is slightly more contrasting; supercilium is better defined and whiter in front of eye (but shorter behind), and blackish-brown eye-stripe is more distinct. Rest of upperparts drab rufous-brown. Underparts also distinguish grey-sided from chestnut-crowned, being greyish-white in center with upper flanks washed ash-grey and lower flanks brownish-grey; undertail coverts brown-buff. Japanese bush warbler is larger with buffish flanks. Juvenile darker than adult, with brownish-olive underparts, and lacks chestnut cap. Juvenile chestnut-crowned has more contrasting whitish throat and belly. Upper mandible grey, lower mandible grey with yellow base. Feet dull brownish-pink. Distinct, two-part song, the first a short, cheerful warble, similar to chestnut-crowned but shorter and faster, the second a squeaky “wheezuu-wheezuu” sounding like the air being squeezed out of a child’s rubber ducky. Sharp call “pseep” has more r-sound than chestnut-crowned, something inbetween a bunting and olive-backed pipit. — Craig Brelsford
THE CETTIID WARBLERS OF CHINA
shanghaibirding.com covers most of the species in China in the family Cettiidae. Click any link:
Yellow-bellied Warbler Abroscopus superciliaris
Rufous-faced Warbler A. albogularis
Black-faced Warbler A. schisticeps
Mountain Tailorbird Phyllergates cuculatus
Broad-billed Warbler Tickellia hodgsoni
Japanese Bush Warbler Horornis diphone
Manchurian Bush Warbler H. borealis
Brown-flanked Bush Warbler H. fortipes
Hume’s Bush Warbler H. brunnescens
Yellow-bellied Bush Warbler H. acanthizoides
Aberrant Bush Warbler H. flavolivaceus
Grey-bellied Tesia Tesia cyaniventer
Slaty-bellied Tesia T. olivea
Cetti’s Warbler Cettia cetti
Chestnut-crowned Bush Warbler C. major
Grey-sided Bush Warbler C. brunnifrons
Chestnut-headed Tesia C. castaneocoronata
Asian Stubtail Urosphena squameiceps
Pale-footed Bush Warbler U. pallidipes
ACKNOWLEDGEMENTS
Daniel Bengtsson served as chief ornithological consultant for Craig Brelsford’s Photographic Field Guide to the Birds of China, from which this species description is drawn.
