Mystery of the yellow bird on a branch - it's Chinese and yellow, but what is the species?

Exquisite - but unidentified

CAN anyone identify this bird which is subject of a delicate  painting that is shortly to be sold at auction in Hongkong?

It is the work of  Zhao Shao'ang (1905-1998) and is entitled Yellow Bird on Branch.

By contrast with western artists, their Chinese counterparts, though often fascinated by birdlife, seem unconcerned with species identification.

Christie's expect the  picture, which measures 96cm x 36cm,   to fetch up to 40,000 HK dollars(£3,765) when it goes under the hammer tomorrow, Tuesday August 18.