The yellow, red, orange, and brown birds of the world assume their hues because of a pigment embedded in the keratin matrix of feathers.

这种集黄色，红色，橙色和棕色于一身的鸟类，能够呈现出如此多的色彩，得益于它的羽毛角蛋白间质里含有色素。

youdao

The green, yellow and grey birds are originally from south America but are living wild in the south of England after being released from captivity in the 90s.

这种绿色、黄色和灰色的小鸟最初来自南美洲，但自从20世纪90年代从笼中放生以来就一直生活在英国南部的野外。

youdao

Any of various old world passerine birds of the family oriolidae of which the males are characteristically black and bright yellow or orange.

黄鹂，金莺一种东半球黄鹂属燕雀鸟类，其雄鸟以黑色和鲜艳的黄色或桔黄色为特点。

youdao

When he received the notice to kill his unsold chickens, Mr. Shi and co-workers grabbed the yellow birds one at a time, cut their necks and removed their feathers, then tossed the remains into one of two large, blue plastic containers for disposal.

WSJ: China Kills Market Birds as Avian Flu Deaths Rise

Although he cannot definitely rule out a direct effect by the pollution on the birds' metabolism of the yellow pigment, or its incorporation into their feathers, the correlation between a shortage of caterpillars and faded plumage is strong evidence of a link between pollution, diet and bird colour.

ECONOMIST: Great tits

Both birds, the Peruvian warbling antbird and the yellow-breasted warbling antbird, belong to the same large family.

BBC: Songbirds sing cross-species duet