They get their name not from their skin color, which tends to be olive to gray, but rather from the blue-black color of the inside of their mouth, which they display when threatened.
A yellow and olive warbler (Oporornis philadelphia) of eastern North America, having a bluish gray hood set off by a black band on its breast.
一种分布于北美东部地区的黄色和橄榄色的林莺（哀林莺） ，长有淡蓝灰色的羽冠，胸口衬有黑条纹。
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Colour resembling unripe olives, olive is a modified spectral colour that is produced through a mixture of green and yellow with either gray or brown pigments of varying proportions.