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

Whether such birds will turn out to be yellow remains to be seen.

ECONOMIST: A genetic game of chicken

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

BBC: Songbirds sing cross-species duet

Once inside the southern Tanzania park, the highway cannot be seen or heard, but it makes Mikumi one of the most accessible places in Tanzania to see lions, buffalo, hippopotamus, gazelles, elands, warthogs and yellow baboons (not to mention more than 400 species of birds).

BBC: Tanzania��s alternative to the Serengeti

Birds, shaking their wings, threw up sprays of yellow powder.

NEWYORKER: The Invasion from Outer Space

Half-asleep, I shuffled to the canopy-level observation deck of my rustic wooden cabin, grabbing binoculars and Tito Narosky's "Birds of Argentina and Uruguay" just as a flurry of yellow plumage transformed into what locals term the "banana toucan, " a rare and striking saffron toucanet.

WSJ: Bird Watching in Misiones Province, Argentina