Manchurian Bush Warbler Horornis canturians borealis breeds Liaoning, Jilin, and Heilongjiang and Korean Peninsula and Russian Far East, and canturians breeds in region ending just south of Yangtze River and extending west through Qin Mountains into Sichuan and north to Hubei. In Yangtze valley canturians has year-round presence. Also winters down entire southern Chinese coast and as far inland as Yunnan. Some borealis winter in Taiwan. HABITAT & BEHAVIOR Dense forest and thick scrub in lowlands, to 700 m (2,300 ft.). Usually stays well-hidden in undergrowth. Breeding male sings from exposed perch. ID & COMPARISON Highly sexually dimorphic. Males much larger than females, which are close in size to Japanese Bush Warbler H. diphone. Forehead and crown rufous, usually contrasting noticeably with plain warm brown plumage on upperparts and tail. Some individuals have plainer brown forehead and crown, hence lacking contrast. Long, buffy-white supercilium. Blackish-brown eye-stripe. Underparts buffish-white with varying buff-brown wash on breast, belly, flanks, and undertail coverts. The two ssp. of Japanese Bush Warbler (cantans and riukiuensis) most likely to be found in China usually lack distinctly rufous pigmentation on crown, have colder olive-grey tone to brown upperparts and less distinct supercilium, and more often seem to show less buff underparts than Manchurian. Male Manchurian noticeably larger than Japanese Bush Warbler. Brown-flanked Bush Warbler H. fortipes is noticeably smaller than even female Manchurian, lacks rufous pigmentation on crown, and is drabber. Grey-sided Bush Warbler and Chestnut-crowned Bush Warbler are smaller. Grey-sided has greyer underparts and Chestnut-Crowned has strongly contrasting chestnut crown spilling over to supercilium (in front of eye). BARE PARTS Bill blackish above, with yellow base to lower mandible. Feet brownish-pink. VOICE Highly vocal. Song, lasting about 2 seconds, begins with a bubbling whistle and ends with a louder flourish. Call a repeated tret or more sparrow-like tschuk. — Craig Brelsford
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.
